Energy Engineering Pune University MCQs
Energy Engineering Pune University MCQs
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Necessity of a Steam Plant”.
1. Apart from geographical location, the amount of power generated in a country depends on ___________
a) Number of power producing plants
b) Annual consumption of power
c) Utilization of natural resources
d) Quantity of requirement
Answer: c
Explanation: Since most of the power produced is from the natural resources, the estimation of amount of power generated in a country is made by the utilization of its natural resources. The ‘Annual consumption of power ‘would give you the details of power utilized for necessities, it is the amount of power utilized out of wholesome amount of total power produced in the country.
2. Total power generated is usually contributed by power generated through ____________
a) Hydel power plant, Thermal power plant and solar plant
b) Ocean thermal energy, Wind energy and Hydel power plant
c) Hydel power plant, Geo-thermal plant and Nuclear power plant
d) Hydel power plant, Thermal power plant and nuclear power plant
Answer: d
Explanation: The energy or power produced from hydel power plant, thermal power plant and nuclear power plant is very abundant compared to any other combinations of power producing plants. All these three plants have ability to produce the power in thousands of megawatts in its own standards.
3. On what factors does hydel plant entirely depend?
a) Vegetation
b) Tropical cycle
c) Amount of Rainfall
d) Hydrological cycle
Answer: d
Explanation: Hydrological cycle is an explanation of the continuous movement of water above and below earth surface, where as rainfall is not reliable since it varies period to period. The amount of water above the earth surface and below the earth surface, both are responsible for the hydrological cycle. ‘Vegetation’ is info about the assemblage of plant species irrespective of their geographic characteristics.
4. The steam power plant serves as a base plant for ________
a) Nuclear power plant
b) Geothermal power plant
c) Thermal power plant
d) Diesel plant
Answer: a
Explanation: Since power is generated by nuclear power plant and the nuclear plant needs power to perform its operations. For this purpose steam power plant is used as base power plant to generate this power. The power produced base plant acts as a fuel to run the nuclear power plant. And all the cost estimation to produce the electricity is made by considering base load expenses too.
5. What is the primary objective of a steam power plant?
a) To convert one form of energy into another form
b) To produce electricity
c) To provide employment
d) To serve as a base load plant to hydel plant or nuclear plant
Answer: b
Explanation: The primary objective of the steam power plant is to produce electricity and then serving as base load plant to hydel or nuclear power plant comes as second priority. Steam power plants produce 86% of electricity. And the efficiency of steam power plant is typically 33%-48%.
6. A steam power plant works on ___________ cycle.
a) Otto
b) Brayton
c) Hydrological
d) Rankine
Answer: d
Explanation: Rankine cycle is a thermodynamic cycle of constant pressure engine that is to convert heat energy into mechanical work and from that following parts like adjoined blades and shafts are made to run to produce electricity. Otto cycle is used in automobile engine and Brayton cycle is used in heat engines & air jet engine.
7. Coal crushers are also known as__________
a) Lather
b) Coal combers
c) Feeder breakers
d) Coal washer
Answer: c
Explanation: Coal crushers are also known as feeder breakers since it is elaborated by the word itself. ‘Feeder’ depicts the following component coal being fed by the hoppers and ‘Breaker’ stands for breaking off into smaller pieces. And this synonym is rarely used.
8. Road transportation of coal is preferred for what type of usage?
a) Small capacity plant
b) Medium capacity plant
c) Large capacity plant
d) Domestic usage areas
Answer: a
Explanation: Road transportation of coal is ideal transporting coal directly to point of consumption. These small capacity plants are usually located in the middle of land. Trucks and tippers are used to supply coal for this purpose. And also when the plant doesn’t have railway or shipway accessibility in such areas roadways are only possible means of transportation.
9. Which is the more economical way of transporting coal?
a) Sea or River ways
b) Railways
c) Road transporting
d) By Airlifting
Answer: b
Explanation: We do know shipways are cheaper. But we need another mode of transport to transfer that coal to the plant area. But in case of railways the tracks can be made to directly pass through the plant. Hence the railway is more economical compared to any other means of transport.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Cool and Ash Handling System – 1”.
1. What is the role of breaker house in coal feeding?
a) To break the coal into smaller pieces
b) To separate different sizes of coal
c) To separate the light dust from the coal
d) To powder the coal
Answer: c
Explanation: Because of the brittle nature of the coal, it is a common nature of coal to emit light dust/coal dust during transportation, mining and machine handling. This dust needs to be cleared out and it is performed by coal breaker.
2. When coal is being burnt how much % of ash is formed compared to the whole amount?
a) 10-20%
b) 40-50%
c) 25-35%
d) 4-10%
Answer: a
Explanation: The coal available in nature already contains some percent of ash and when it is burnt. Due to its brittle nature more amount of ash is produced. And coal is one of the largest types of industrial waste generated. For environmental benefits, this coal ash is reused as a type of by-product in different types of industries.
3. Why is it important to prefer ash handling systems?
a) Coal ash produced destroys the machinery by entering into them
b) Coal ash produced annually accounts for thousands of tones
c) Coal ash can be reutilized for some other purpose
d) Coal ash affects the health of people working at plants
Answer: b
Explanation: Considering the large coal burning capacity plant of modern times, the amount of ash produced when the coal is burnt is in thousands of tones. It could have an effect on other subjects too if the proper ash handling methods are not followed. And for different environmental, economical and product benefits the coal ash is reused by different types of industries in different ways of its necessity.
4. Large amount of coal is transported by ________
a) railway
b) sea or river ways
c) road transportation
d) by airlifting
Answer: a
Explanation: The railway is preferred since it is quite economical as well as loading and unloading of coal is easy. And at stretch tons of coal can be transported by goods train from one place to another place. Coal is considered as a bulk commodity value which falls in category of minerals and ores. If roadways are preferred only minimal amount of load can be transported. But by railway, long distances with huge amount of coal can transported to any region/part of the country.
5. The coal is fed to the furnace through _________
a) conveyor belt
b) wagon tipper
c) hopper
d) crane
Answer: c
Explanation: Hopper is the conical shaped slow coal dispenser to the furnace. It is placed right above the furnace and a live feeder mechanism is set at end of hopper for a controlled flow. There is no requirement of any external power/force since this works on gravity force.
6. Which system consumes less power out of all ash handling systems?
a) Mechanical ash handling system
b) Pneumatic ash handling system
c) Hydraulic ash handling system
d) Steam jet ash handling system
Answer: a
Explanation: The mechanical ash handling system consumes less amount of power. Since the power is required by the conveyor belt to transfer the ash from boiler furnace to over head bunker which is located at end of the conveyor belt. And in case of pneumatic there is high power requirement to draw and blow the air at high velocities and high pressures.
7. What is the function of cyclone separators in pneumatic ash handling system?
a) To separate the lighter dust particles
b) To force up the movement of ash through pipes or tubes
c) To draw out the dust from furnace
d) To separate minute coal particles
Answer: a
Explanation: Cyclone separators use air to swirl around the ash that has been dispensed into them. Due to centrifugal action heavier ash settles down, where as lighter dust/ash particles is collected in hopper and dumped out. The air flows in helical pattern which makes easy for the heavier dust particle to settle down easily without interrupting the airflow.
8. Which medium is used to carry ash in the pneumatic ash handling system?
a) Conveyor belt
b) Water trough
c) Air
d) Chain belt
Answer: c
Explanation: In pneumatic ash handling system, Air is used to carry ash to long distance at a capacity of 5 to 30 tonnes per hour. And the air used for this purpose is easily cleanable and can be exhausted back into atmosphere after the complete filtration processes.
9. Which system is noisy out of all the following ash handling systems?
a) Steam jet ash handling system
b) Mechanical ash handling system
c) Pneumatic ash handling system
d) Hydraulic ash handling system
Answer: c
Explanation: The air is made to pass at very high pressure in order to carry out the ash for long distance. Since the air is moving at high speed at high velocity in the conveying pipes, it tends to create a lot of noise by hitting the walls of pipe at swift turns and curves.
10. Which medium is used to carry ash in hydraulic system?
a) Air
b) Water
c) Steam
d) Conveyor
Answer: b
Explanation: Water is used as the medium to carry ash at high velocity. Depending on water pressure the system is divided as Low pressure system and High pressure system. In low pressure system, sloped sumps are used to move the ash at low velocity and in high pressure system nozzle sprays used to ram up the speed of ash flow.
11. What would be the amount of distance that a low pressure system could carry the ash?
a) 25m
b) 500m
c) 150m
d) 800m
Answer: b
Explanation: Low pressure system moves the ash mixed in water at a distance of 3 to 5 m/s in a sloped pump made of reinforced constituents and this movement is continuous. So, it has the ability to carry the ash for such long distance. There is no requirement any auxiliary source to move the ash mixed with water.
12. What is the capacity of low pressure hydraulic ash handling system?
a) 80 tonnes/hour
b) 22 tonnes/hour
c) 50 tonnes/hour
d) 10 tonnes/hour
Answer: c
Explanation: The capacity of low pressure hydraulic ash handling system is 50tonnes/hour at a speed of 3m/s. Since the ash produced is mixed in water and dumped, the water has the ability to dissolve and intake more amount of ash. And this mixture is spread throughout the sump.
This set of Energy Engineering Interview Questions and Answers focuses on “Coal and Ash Handling System – 2”.
1. _________ is used in high pressure hydraulic ash handling system, to quench the ash.
a) Turbines
b) Lubricants
c) Water troughs
d) Nozzle sprays
Answer: d
Explanation: As we know Nozzles are used to increase pressure. Also, they are also used to quench the ash. The ash falling from the conveyor belt is quenched to make it flow down through the sump. Water trough is used in order to avoid dust creating from falling ash from the furnace.
2. Which of the following ash handling system is more suitable for large thermal plants?
a) Steam jet ash handling system
b) Mechanical ash handling system
c) Pneumatic ash handling system
d) Hydraulic ash handling system
Answer: d
Explanation: Hydraulic ash handling system is more suitable large thermal plants since its ash carrying capacity is considerably large. And also it has ability to dissolve the ash in the water which makes its capacity large. It also has lots of advantages it is clean, dust free and no noise is produced. The water used can be recycled only for limited amount of times.
3. What is the important feature of hydraulic ash handling system?
a) It is clean and dustless
b) It can discharge ash for long distances
c) The unhealthy aspect of ordinary ash basement work is eliminated
d) Absence of working parts in contact with ash
Answer: d
Explanation: Particularly in hydraulic system the ash is actually quenched in water. So, there is less chance that ash has any possibility of getting in contact with the machineries. There is less chances of machine falling into a repair and maintenance is less as compared to any other type of ash handling system.
4. In hydraulic ash handling system, large quantities of leachate under a positive pressure head in pond pose a constant threat to ________
a) cause pungent smell
b) the livelihood
c) ground water quality
d) the nearby flora
Answer: b
Explanation: Since there is constant gravity pressure that is exerting on the surface of the ponds or other water bodies where hydraulic ash is dumped. When the same water is absorbed into the ground, it affects the quality of ground water. This effect indirectly affects growth of plants and degrades the land around water body making it unusable.
5. Which of the following ash handling system is not flexible to re-locate/re-place its discharging site?
a) Steam jet ash handling system
b) Mechanical ash handling system
c) Hydraulic ash handling system
d) Pneumatic ash handling system
Answer: c
Explanation: Since the hydraulic ash handling system involves the usage of liquids, the discharging sites cannot be re-located/re-placed. Else constructing/developing a new discharging site is possible but the old one cannot be replaced since it is a wet system. In case of all other forms of ash handling system it is easy since they are dry system and they won’t have much of an impact on the following discharging site/land.
6. ___________ and __________ are the common problems on pipeline inner walls when the slurry contains calcium, magnesium and sulphate ashes.
a) Clogs and Corrosion
b) Scaling and Cracks
c) Pores and Contamination
d) Scaling and Cementation
Answer: d
Explanation: Scaling and Cementation are the two main problems caused on the inner walls of pipeline, when there is contamination of calcium, magnesium and sulphate in the discharge. Calcium or magnesium contained mixtures have limited solubility. So, they intend get deposited on the materials.
7. Which of the following ash is suitable for selling?
a) Bed ash
b) Synthetic gypsum
c) Fly ash
d) Clinkers
Answer: c
Explanation: Fly ash is sold in the market, which is used in concrete bricks, cement clinkers, road subbase and as mineral filler in asphaltic concrete. Fly ash is very fine in its structure, composed mostly of silica made from burning of coal in the furnace or boiler. And ‘Bed ash’ refers to the ash that’s struck on the walls of boiler which is very coarse in nature.
8. Which ash handling system can be built up in limited space?
a) Mechanical ash handling system
b) Pneumatic ash handling system
c) Hydraulic ash handling system
d) Steam jet ash handling system
Answer: d
Explanation: Steam jet ash handling system can be constructed particularly when there is a limited amount of space is available because not much amount of space is required for its setup and operation. Pneumatic and hydraulic ash handling system require huge amount of space for their construction and operation. Steam jet ash handling system is used in small capacity plants.
9. In what form does the total ash produced in the furnace escapes through the chimney?
a) Fines
b) Aerosols
c) Gas
d) Cinder
Answer: a
Explanation: Fines are the particles which vary in the size of 1 to 80 microns. These could easily get escaped into air via chimneys. About 80% of ash produce is in this range of microns and everything gets easily escaped into air and the rest is made use for other possible purposes.
10. What is the capacity of the steam jet ash handling system?
a) 45tonnes/hour
b) 15tonnes/hour
c) 30tonnes/hour
d) 150tonnes/hour
Answer: b
Explanation: The capacity of the steam jet ash handling system is limited 15tonnes/hour since the plant built up is in less space. And it has ability to remove ash through a horizontal distance of 200m. the operation of this system is noisy since steam jet of high velocity is produced in such a limited place.
11. What material is used in pipe linings for linking of steam jet system?
a) Nickel alloy
b) Graphite
c) Titanium
d) Copper alloy
Answer: a
Explanation: The abrasive particles present in ash cause wear and tear in pipes due to high speed movement in pipes of steam jet system. Even chilled iron also can be used to line the pipes to overcome the following problem. And also avoiding bends and turns in pipes would reduce the damage of pipes.
12. What is the distance up to which steam jet ash handling system is capable of removing ashes?
a) 200m
b) 50m
c) 75m
d) 350m
Answer: a
Explanation: Even though the size of the steam jet ash handling capacity is compact, the high velocity steam jet can easily remove the ashes up to 200m. Since it is small sized plant its capability to remove ashes is limited. The moisture of steam also makes the ash wet and it would gain a light amount of weight which becomes a bit difficult to move ash at a longer distances.
13. What measure to be taken to avoid the noise produced in the pneumatic ash handling system?
a) Passing ash at slower pace
b) Reducing swift turns and sharp bends
c) Broadening of pipe width
d) Reducing and crushing the size of the ash
Answer: b
Explanation: The air and ash mixture moving through the pipe at high pressure tends to hit the walls at inner side of pipe when there are number of swift turns and sharp bends made. Avoiding them can reduce the noise up to 50%.
14. Is there any requirement of auxiliary steam producer in the steam jet ash handling system.
a) True
b) False
Answer: b
Explanation: There is no requirement for any auxiliary steam producing unit since the steam required is drawn from the boiler present in the system. The steam drawn from the boiler is pressurized and then utilized. Non-requirement of auxiliary unit is advantageous as it would cut slack in the expenses of setting up the plant.
15. How much amount of steam is required to remove 1 ton of ash from the steam jet ash handling system?
a) 100kg
b) 450kg
c) 65kg
d) 200kg
Answer: a
Explanation: 100 kg of steam is required to remove 1 ton of ash. Since the steam let out is at very high velocity, 1 ton of ash can be easily moved to compare and balancing to its weight ratio. And this wholesome amount of steam is generated by the boiler present in the plant.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Cooling Water System, Air & Fuel Gas System”.
1. What type of draught fan is used to draw air from the air heater?
a) Balanced draught fan
b) Induced draught fan
c) Forced draught fan
d) Artificial draught fan
Answer: c
Explanation: Forced draught fan is used to draw the air. This is installed near the base of boiler and air is forced to pass through the furnace, economizer and to the air stack. This is also called a positive draught system because pressure and air is forced to flow through the system.
2. In what form are the products of combustion in steam powered plant?
a) Air products
b) Flue gas
c) Slurry
d) Hot water
Answer: b
Explanation: The products of combustion are in form of flue gas. Flue gas is the gas which is exiting to the atmosphere via a flue, which is channel for releasing exhaust gas from steam power plant. The flue gas is high in the contamination of nitrogen, oxygen and carbon dioxide. And also it contains a small amount of pollutants, such as soot and other types of oxides.
3. How flue gas is made use of in steam power plant?
a) To maintain the constant pressure inside boiler
b) To heat the water in the tubes of boiler
c) To increase or decrease the pressure inside the boiler
d) To remove all unnecessary chemical constituents
Answer: b
Explanation: The flue gases are circulated in the furnace to heat the water in tubes. First it is passed over economizer and then to the pre-heater. And then finally after making maximum utilization of the flue gas they are exhausted through chimneys.
4. How is flue gas discharged through the chimneys?
a) By using induced draught fan
b) By using balanced draught fan
c) By using forced draught fan
d) By using mechanical draught fan
Answer: a
Explanation: After extracting maximum possible heat by circulating the flue gas in furnace. Induce draught fan is used to remove the left over gas via chimney. This is located near the base of the chimney. The air is sucked in by reducing the pressure below atmosphere. The draught produced is independent of temperature of hot gases.
5. What is the purpose of chimney?
a) To provide air ventilation
b) To eliminate noise produced in the system
c) To exhaust flue gases those is induced
d) To help in to suck the air required for system
Answer: c
Explanation: Chimneys are actually used to remove exhaust gases or products of combustion by using induced draught system. Almost all chimneys are constructed by bricks vertically and at a certain height in order easily release flue gases into atmosphere. The height of the chimneys shows its ability to transfer flue gases. The deposits of flue gas contaminations are made on the inner walls of the chimney.
6. What is the advantage of using flue gas inside a boiler?
a) Heats up boiler water tube quickly
b) Reduces the amount of amount of exhaust
c) Speeds of the process of boiler
d) Reduces the green house of effect
Answer: d
Explanation: Using flue gas to heat up the water tubes reduces the greenhouse effect indirectly by making use of its heat to turn the water in water tubes into steam. This will be used in steam power plant to rotate the turbine and to produce electricity. And also plant operators can operate at best heat rate efficiency.
7. How is water pumped into condenser tubes in the steam power plant?
a) Water clarifier plant
b) Draught systems
c) Hydraulic capacity electric motor pump
d) Drawing through water
Answer: a
Explanation: The water is pumped into condenser tubes through water clarifier plant. Clarifier helps in suspending solids from water in order to avoid damages to condenser tubes. Clarifiers are available in wide varieties of capacities of capacities and shapes depending on the steam plant.
8. When is the cooling tower preferred?
a) When there is plenty of water available
b) When there is scarcity of water
c) When the plant is of large capacity
d) When the amount of flue gas produced is very high
Answer: b
Explanation: Cooling tower is preferred when there is scarcity of water. Instead of circulating the water directly, it is sprinkled in the cooling tower to condense the exhausted steam coming from the turbine. The loss of water due to evaporation is compensated by supplying water directly from the river.
9. What type of system is it, when the water is directly is used to condense the steam?
a) Closed system
b) Open system
c) Closed loop system
d) Open loop system
Answer: b
Explanation: Water is pumped through the water clarifier plant and is used to circulate through the condenser in order to condense the steam coming out from the turbine. Water leaving the condenser is discharged to the downward side of the river. The amount of water in taken from river, the same amount of water is discharged back to river with the minimal temperature difference. And this following system is called open system.
10. How is the amount of cooling required by the steam power plant determined?
a) By the capacity of plant
b) By the amount of exhausted gas
c) By its thermal efficiency
d) By the type of fuel used
Answer: c
Explanation: The amount of cooling required by the steam power plant is determined by its thermal efficiency. It has nothing to do whether it is fueled by coal or uranium; neither has it depended on the type of power plant . Nuclear power plants have lower thermal efficiency than thermal plants. Higher the thermal plants lower the water usage for cooling.
11. How much amount of water does typical 1GWe plant uses for cooling per day?
a) 30 mega litre
b) 45 mega litre
c) 55 mega litre
d) 75 mega litre
Answer: d
Explanation: Water is used in a plant to convert it into steam and utilize it for developing mechanical energy as well as it is used for the cooling of the steam produced. This water is supplied by the large water bodies like river or big lakes. The amount of utilized from water body is all discharged back at the end.
12. What type of system is it when the cooling tower is preferred?
a) Closed system
b) Open system
c) Closed loop system
d) Open loop system
Answer: a
Explanation: When there is a scarcity of water a cooling tower is installed, such system is known as the closed system. In this system the condensed water is cooled by passing it through the cooling tower and water is sprinkled over steam. The loss of water due to evaporation is compensated by supply of water directly from the river.
13. What is the alternative cooling method for the thermal plant?
a) Wet cooling
b) Evaporation cooling
c) Dry cooling
d) Central air damping
Answer: c
Explanation: The alternative way of cooling method is dry cooling. Where in this method the heat is directly transferred to air via high flow forced drafts [industrial sized fans]. This is less efficient compared to wet cooling method since it uses very high amount of power to rotate the fans. Dry cooling method is very useful in the desert areas, where water scarcity is a huge problem.
14. How can we achieve high thermal efficiency in a power plant?
a) Drawing high output with limited input
b) Decreasing the working temperature
c) Increasing the working temperature
d) Maintain large temperature differential
Answer: d
Explanation: The amount of heat discharged to environment depends on the plants thermal efficiency. High efficiency is achieved by having a large temperature differential. Irrespective of whether it comes from high internal heat or low temperature external environment, or both. The thermal efficiency of today’s nuclear power plant is around 35% whereas hotter coal burners can reach 40% or more. At last higher thermal efficiency is required to lower the water usage.
This set of Energy Engineering Questions and Answers for Freshers focuses on “Feed Water and Steam Generation System, Working of Thermal Power Plant”.
1. What is the storage used to hold the condensed water?
a) Reservoir
b) Tarn
c) Hot well
d) Basin
Answer: c
Explanation: Hot well is used for storage of the condensed water in a power plant. A tank or reservoir in which hot water is collected before being recirculated, especially condensed steam about to be returned to a boiler is called Hot well.
2. Feed water from the hot well is supplied to steam generator by using the _________
a) Sewers
b) Cistern
c) Water trough
d) Feed pump
Answer: d
Explanation: Feed pump is used to pump/supply feed water from hot wall to steam generator. The water may be freshly supplied or returned condensate produced by the boiler. These pumps are positive displacement generator and are of very high capacity.
3. Super heater tubes are made up of what type of material?
a) Copper alloy
b) Carbon steel
c) Titanium alloy
d) Iron
Answer: b
Explanation: The steam generated in the boiler is superheated in super heater tubes made of carbon steel for operating at a steam temperature of up to 950°F and carbon molybdenum steel for operating at steam temperature of 1050°F and stainless steel for operating temperature of 1200°F. The tubes of super heater have an outside diameter which ranges from 25mm to 64mm.
4. By what means the power in the steam power plant is developed?
a) Condenser
b) Electric power system
c) Prime mover
d) Economizer
Answer: c
Explanation: The prime move s used to develop power in the steam power plant. The water is heated, turns into steam and is made to enter into steam turbine. The steam spins and it drives electric generator connected to it, which generates electricity.
5. Chemicals are added in the feed water.
a) True
b) False
Answer: a
Explanation: Chemicals are put into feed water through the chemical feed tank to keep water within chemical range. These chemicals are mostly oxygen scavengers and phosphates. The boiler water also has frequent blow downs in order to keep the chloride content down.
6. What is the main objective beyond treating feed water?
a) To remove solid particle
b) To prevent damage by scaling
c) To speed up the steaming process
d) To control conductivity
Answer: b
Explanation: The main objective to treat feed water is to prevent damage by scaling and exchange heat without scaling to produce high quality steam. Since a high amount of water is converted into steam back and forth, there is pretty good chance of scale formation in the tubes if the water is not treated.
7. What is the pH value at which the boiler is alkalized?
a) 9.0
b) 5.4
c) 6.9
d) 5.7
Answer: a
Explanation: The boiler is alkalized to pH value of 9.0 to reduce oxidization and to support the formation of a stable layer of magnetite on water side surface of the boiler protecting from oxidation. And also oxygen scavengers are used to remove residues of oxides, especially O 2 & CO 2 [oxygen and carbon dioxide] must be removed. Sodium hydroxide or ammonia is used for alkalization of the feed water.
8. What does steam power plant mainly use to generate steam?
a) Boiled water
b) Fresh steam
c) Flue gas
d) Condensed water
Answer: c
Explanation: Steam power mainly uses hot products of combustion known as flue gas to generate steam in a boiler. Heat is generated by burning coal, oil or gas. For this purpose boiler furnace is designed for firing coal, air or gas. The flue gas is exhausted via chimney after making maximum utilization of it.
9. What type of steam is produced in the steam boiler?
a) Low pressure steam
b) High pressure steam
c) Saturated steam
d) Unsaturated steam
Answer: c
Explanation: The boiler is an integral component of steam engine. A boiler incorporates a firebox or furnace in order to burn the fuel and generate heat. The generated heat is transferred to water to make steam. This produced saturated steam at a rate which can vary according to pressure. The saturated steam thus can produced can either be used immediately to produce power via turbine.
10. What is the main purpose of using an economizer in a boiler?
a) To control the process of steam conversion
b) To reduce energy consumption
c) To increase the temperature of boiler
d) To maintain a constant temperature inside a boiler
Answer: a
Explanation: Economizer in boilers is used to heat fluids, upto a certain degree not beyond the boiling point of that fluid. Economizers are named so because they can make use of enthalpy in fluid stream that are hot, thereby making more useful enthalpy and improving the boiler’s efficiency.
11. In what form is the coal used in boiler?
a) Big chunks.
b) Medium size crushed
c) Powder form
d) Mixed with fluid
Answer: c
Explanation: The coal used for boiler is in powder form, in order to increase thermal efficiency. The different types of coal used in boiler are generally bituminous coal, brown coal and peat. Commonly bituminous coal is most preferred boiler fuel since it has volatile matter from 8 to 33% and ash content of 5 to 16 %.
12. Why is air pre-heater used in the boiler?
a) To draw in the atmospheric air
b) To increase thermal efficiency
c) To heat the air to superheated level
d) To heat the air in advance
Answer: b
Explanation: the purpose of the air preheater is to recover the heat from the boiler flue gas which increases the thermal efficiency of the boiler by reducing the useful heat lost in the flue gas. As a consequence the flue gases are also conveyed to the flue gas struck at a lower temperature, allowing simplified design of conveyance system and flue gas stack.
13. What is the advantage of condensing the steam?
a) To cool down the steam
b) To discharge the same amount of feed water taken
c) Reduces the amount of pollution
d) Reduces the amount of fresh feed water
Answer: d
Explanation: The principle advantage of condensing operation is to reduce the amount of fresh feed water. A condenser is usually installed after the turbine to convert the exhaust steam from the turbine. They convert gaseous steam into liquid state, at a pressure below atmospheric temperature. Condensing of steam turbine below the atmospheric temperature, the steam pressure drops between the inlet and exhaust of turbine is increased, which increases amount of heat available.
14. How is water dispensed over to the turbine blades?
a) Trough
b) Nozzle
c) Hose
d) Pump
Answer: b
Explanation: Nozzle is used to dispense the water over to the turbine blades of steam turbine. A nozzle is a duct that increases the velocity of the flowing fluid at the expense of pressure drop. It’s a duct which decreases the velocity of fluid and increases pressure difference.
15. In what aspect does the nozzle make changes?
a) Temperature
b) Volume
c) Pressure
d) Density
Answer: c
Explanation: Nozzle makes changes in terms of pressure variation. And rest all factors/terms are unaffected. By decreasing the pressure and increasing the velocity at other end through convergent-divergent nozzle, the required force or pace can be achieved to run the blades of turbine.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Fuels and Combustion”.
1. In presence of which gas is the fuel burnt to generate energy in the form of heat?
a) Oxygen
b) Hydrogen
c) Methane
d) Nitrogen
Answer: a
Explanation: The fuel is burnt in the presence of oxygen to generate energy in the form of heat. This heat energy can be used for electrical power generation in steam power plants and for propelling ships, automobiles and locomotives, etc.
2. Which are the main constituents of fuel from given options?
a) Carbon and Nitrogen
b) Oxygen and Hydrogen
c) Carbon and Hydrogen
d) Helium and Oxygen
Answer: c
Explanation: Carbon and Hydrogen are the main constituents of a fuel. In addition to them, fuel also contains sulfur, oxygen and nitrogen in minimal quantities. Depending on the fuel, the percentage of carbon ranges from 50-95%, hydrogen (H 2 ) 2-6%, oxygen (O 2 ) 2-4%, sulfur (S 2 ) 0.5-3% and Nitrogen 5-7%. A solid fuel may also contain 2-30% ash. In a fuel carbon, hydrogen and sulfur are combustible elements whereas nitrogen and ash are incombustible elements. Since the major combustible elements in fuel are carbon and hydrogen it can also be called as Hydrocarbon fuel.
3. Which fuel is used widely in steam power plants?
a) Oil
b) Gas
c) Coal
d) Petroleum
Answer: c
Explanation: Coal is the oldest form of fuel and is still used in a large scale throughout the world by steam power plants as well as all power generation plants. Coal is a heterogeneous compound and its constituents are always carbon, hydrogen, oxygen, sulfur, nitrogen and certain mineral non combustibles.
4. What is the phenomenon of the formation of coal called?
a) Metamorphism
b) Diagenis’
c) Photosynthesis
d) Protolith
Answer: a
Explanation: The phenomenon by which the buried vegetation consisting wood, grass, shrubs etc, transformed into coal is known as metamorphism. The nature of coal will depend upon the type of vegetation buried and nature and duration of metamorphism. There are different types of metamorphism namely contact metamorphism, regional metamorphism, cataclastic metamorphism, hydrothermal metamorphism, burial metamorphism and shock metamorphism.
5. On what basis is the coal classified?
a) Period of formation
b) Depending on capacity to burn
c) Region/area where is it formed
d) Physical and chemical composition
Answer: d
Explanation: The coal is classified on the basis of its physical and chemical composition. The proximate and ultimate analyses are the common tests which are used to find the commercial value of the coal. The proximate analysis gives characteristics of coal such as percentage of moisture, ash and volatile matter. Analysis of coal gives an indication about fusion temperature and heating value of the coal.
6. What is the use of electrostatic precipitations in steam power plant?
a) To remove the steam
b) To draw the coal powder into boiler
c) To remove the feed water
d) To remove fly ash
Answer: d
Explanation: The electrostatic precipitators are extensively used in the steam power plant for removal of fly ash from the electric utility boiler emission. Since the water inside the boiler is converted into steam, the fire for converting is fuelled by burning the coal which produces high amount of fly ash, so that the ash’ can be reused. The use of electrostatic precipitators is growing rapidly because of the new strict air code and environmental laws. An electrostatic can be designed to operate at any desired efficiency.
7. Why is ‘make-up water’ added to drum continuously?
a) To remove the impurities in tube
b) To replace the water that has been converted into steam
c) To keep the system cool externally
d) To compensate for water loss trough blow down
Answer: d
Explanation: Make-up water is added to compensate for the losses of water incurred by blow downs or leakages occurring in boiler, and also to maintain desired water level in boiler steam drum. Blow down and leakages are common since there is continuous flow of condensate from condenser to boiler.
8. What causes failure of boiler tube?
a) Heating the tubes, when desired water level is not maintained
b) Induced pressure in the water
c) Over use of boiler
d) Hardness of water
Answer: d
Explanation: Hardness of water causes failure of boiler tube. Hard water consists of calcium and magnesium salts. Hardness in water will form deposits on the tube water surfaces which will lead to overheating and failure of tubes. Thus the salts have to be removed from the water.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Types of Fuels”.
1. Fuels are classified as primary and secondary fuel based on the __________
a) Capacity to burn
b) Availability
c) State
d) Occurrence
Answer: d
Explanation: Based on the occurrence, fuels are classified as primary fuels and secondary fuels. A primary fuel is available in nature E.g., wood, peat, lignite, natural gas, petroleum, etc. A primary fuel is also called as a natural fuel. A secondary fuel is not available in nature, but it is prepared from primary fuel by artificial means e.g. gasoline, diesel, coke gas, blast furnace gas, kerosene etc. A secondary fuel is also known as artificial fuel.
2. Which fuel is partially carbonized and is considered as a primary stage in coal formation?
a) Coal bitumen
b) Anthracite
c) Peat
d) Lignite
Answer: c
Explanation: Peat is partially carbonized and decomposed material formed mainly due the transformation of buried vegetation. It is considered as the primary stage in the formation of the coal. It is spongy substance with high moisture content . Hence it has to be dried before use. In dry form, it has a calorific value of about 14560 KJ/kg. It consists of 58% C; 6.3% H 2 ; 30.8% O 2 ; 0.9% N 2 and 4% ash.
3. Which fuel is called secondary stage in the formation of coal?
a) Lignite
b) Bituminous coal
c) Peat
d) Anthracite
Answer: a
Explanation: Lignite is the secondary stage in the formation of coal. It is brown in color and hence known as brown coal. It is used as a low grade fuel especially for domestic use and also as a boiler fuel. It is the intermediate stage between bituminous coal and peat. It has a calorific value of about 12500 kJ/kg. It consists of 66% C; 5% H 2 ; 20% O 2 ; 1% N 2 ; 1% S and 3.5% ash and other incombustible.
4. Which fuel is commonly available in both caking and Non-caking forms?
a) Lignite
b) Bituminous coal
c) Peat
d) Anthracite
Answer: b
Explanation: Bituminous coal is the most commonly used form of coal. It is available in both caking and non-caking forms. It burns with a yellow flame. It has calorific value of about 32000 kJ/kg. It consists of 81%C; 5%H 2 ; 8% O 2 ; 1.5% N 2 ; 1% S; and 3.5% ash. Caking bituminous coal softens and forms a pasty mass if heated at higher temperature. This coal is used to manufacture coke. Non-caking bituminous coal doesn’t soften on heating and hence it is used in steam power plants.
5. Which fuel is the final stage in the formation of coal?
a) Bituminous coal
b) Anthracite coal
c) Peat
d) Lignite
Answer: b
Explanation: Anthracite coal is called final stage of transformation of buried vegetation into coal. It is non-caking and has highest calorific value of about 35500 kJ/kg. It burns at high temperature and is smokeless. It consists of 91% C; 3% H 2 ; 2.5% O 2 ; 0.5% N 2 ; 0.5% S and 2.5% ash. It is also used as a boiler fuel.
6. Which form of fuel is used as a domestic form of fuel?
a) Wood
b) Bituminous Coal
c) Dung cake
d) Anthracite coal
Answer: a
Explanation: wood is mainly used as a domestic fuel. It has low calorific value of about 10500 kJ/kg. It consists of about 48.5% C; 6% H 2 ; 1.5% of ash; 43.5% O 2 and 0.5% N 2 . Wood fuel is used in different forms such as firewood, charcoal, chips, sheets, pellets and sawdust. The particular form used depends upon factors such as source, quantity, quality and application.
7. What is the main purpose of demineralization treatment plant?
a) To remove deposits made on tube
b) To reduce scaling on tube
c) To remove salts
d) To filter the boiler water
Answer: c
Explanation: The salts of hard water have to be removed to overcome all types of effects caused by water on tubes. Demineralization treatment plant generally consists of cation, anion and mixed bed exchangers. These ions are recombined with water to form pure water. Very pure mineralized water becomes highly corrosive once it absorbs oxygen.
8. What type of gear mechanism is provided to rotate the turbine generator shaft?
a) Mutilated gear mechanism
b) Ratchet gear mechanism
c) Barring gear mechanism
d) Planetary gear mechanism
Answer: c
Explanation: Barring gear is the mechanism provided to rotate the turbine generator shaft at very low speed after unit stoppages. Once the steam inlet valve is closed, the turbine comes down towards standstill. When it stops completely, there is a tendency for turbine shaft to deflect or bend if allowed to remain in same position for too long.
9. Which gas cooling is used in large generator units of steam plant?
a) Sulfur dioxide
b) Hydrogen
c) Carbon dioxide
d) Nitrogen
Answer: b
Explanation: Hydrogen gas cooling is used for large generator units in steam plant. Because it has the highest heat transfer coefficient of any known heat transfer coefficient of any gas and for its low viscosity which reduces wind-age losses. This system requires special handling during start up, with air in the generator enclosure first displaced by carbon dioxide before filling with hydrogen. This ensures that the highly flammable hydrogen does not mix with oxygen in the air.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Artificial Solid Fuels & Liquid Fuels”.
1. Which fuel is produced by slow pyrolysis?
a) Dung cake
b) Coke
c) Charcoal
d) Briquette
Answer: c
Explanation: Charcoal is produced by slow pyrolysis. It is prepared by heating wood with limited supply of air below 280°C. It contains 80-90% of carbon. It is used for domestic purpose namely cooking, heating and metallurgical purpose. Charcoal is the light weight black carbon and ash residue produced by removing water and other volatile constituents from animal and vegetation substances. There are different types of coal namely sugar charcoal, activated charcoal, lump charcoal, etc.
2. Which fuel is prepared by heating bituminous coal continuously for 15 to 18 hours in closed chamber?
a) Charcoal
b) Anthracite
c) Coke
d) Briquette coal
Answer: c
Explanation: Coal is prepared by heating bituminous coal continuously for 15 to 18 hours in closed chamber in the absence of air 500 o C to 700 o C. During this process the volatile matter is removed from the coal, leaving a dull black color to coke. It is a hard porous structure and smokeless. It contains 85 to 95% carbon. When the bituminous coal is heated between 900 o C to 1000 o C, hard coke is produced. It is used in gas producing plants and blast furnaces.
3. Which fuel is prepared by moulding finely ground coal under pressure?
a) Coke
b) Charcoal
c) Briquette coal
d) Lignite
Answer: c
Explanation: Briquette coal is prepared by moulding finely ground coal under pressure with or without the addition of binding material. Most commonly used binding materials are coal tar, crude oil and clay. By using briquette coal, the fuel loss through boiler grates can be avoided.
4. Which fuel is produced by powdering low grade coal with high ash content?
a) Coke
b) Pulverized coal
c) Charcoal
d) Briquette coal
Answer: b
Explanation: Pulverized coal is prepared by powdering low grade coal with high ash content. Dry coal is pulverized in pulverizing mills. It burns most efficiently when mixed with air and hence it is used in most of the power plants.
5. Which is the correct advantage of solid fuels out of the given option?
a) They have low ignition temperature
b) They produce small amount of smoke
c) They have higher calorific value
d) They do not form any clinker
Answer: a
Explanation: They have low ignition temperature’. Ignition temperature is the minimum temperature at which a substance starts to burn. Different fuels have different ignition temperature. Some fuels have low ignition temperature and some have high ignition temperature. The fuels that have low ignition temperature are highly inflammable and burn quickly at the spark of fire. While some fuels that have high ignition temperature do not burn quickly. They require heating to burn. For e.g., kerosene oil does not burn unless it is heated up to its ignition temperature.
6. Choose the proper disadvantage of solid fuels out of the given option?
a) They produce lot of smoke
b) They have low ignition temperature
c) They are high in production cost
d) They cannot be easily transported
Answer: a
Explanation: Solid fuels tend to produce lot of smoke because they have large percentage of ash content. They are also brittle in nature and they contain some amount of ash in it when they are in ground. Due to their brittleness, it is common nature of solid fuels that they break into pieces while mining and transporting and form ash.
7. In what forms are liquid fuels available in nature?
a) Light distillate
b) Petroleum spirit
c) Petroleum naphtha
d) Crude petroleum
Answer: d
Explanation: Liquid fuels are available in nature in the form of crude petroleum. All commercial liquid fuels are derived from crude petroleum or crude oil. The crude oil, as it comes out from oil wells contains 83-87% carbon, 10-14% hydrogen and small percentages of sulfur, nitrogen, oxygen and gases containing mainly ethane and methane.
8. Name the process used to eliminate impurities present in crude oil?
a) Distillation
b) Filtration
c) Sedimentation
d) Coagulation
Answer: a
Explanation: The impurities present in the crude oil are eliminated by the process of refining oil by distillation. It is based on the principle that boiling points of various hydrocarbons increase with an increase in molecular weight and when distilled, the crude oil is separated into gasoline, kerosene, fuel oil or reduced crude oil.
9. Which fuel has the lightest liquid petroleum fraction?
a) Diesel
b) Petrol
c) Distillate
d) Kerosene
Answer: b
Explanation: Petrol has the lightest liquid petroleum fraction and highly volatile in nature. It is also called gasoline. It has a specific gravity ranging from 0.70 to 0.78. It is obtained between 65 to 200 o C and it is a mixture of a number of hydrocarbons. It is light yellow in color and it is used as a fuel in automobiles and aero planes.
10. Which fuel is heavier than petrol but less volatile and it is commonly used as domestic fuel?
a) Diesel
b) Distilled fuel
c) Kerosene
d) Alcohol
Answer: c
Explanation: Kerosene is heavier than gasoline but less volatile than it. It has a specific gravity ranging from 0.78 to 0.85. It is obtained between 150 to 300 o C. It is mainly used in aviation gas turbines as jet fuel and also in lams and stoves. It is miscible in petroleum solvents but immiscible in water.
11. Which fuel is slightly heavier than kerosene and is produced in petroleum fractions?
a) Diesel
b) Crude oil
c) Gasoline
d) Distillate
Answer: d
Explanation: Distillate is slightly heavier than kerosene and is used as fuel and domestic fuel. It is liquid fuel usually distilled from crude petroleum and produced in fractions. Distillate fuel is a type of fuel for internal combustion vehicles with either mechanical transmissions or electric transmissions. They are used in automobiles locomotives and agricultural machinery as well as space heaters and power generators.
12. Which fuel has higher thermodynamic efficiency in liquid fuels?
a) Diesel
b) Petrol
c) Kerosene
d) LPG
Answer: a
Explanation: Diesel is heavier than kerosene. It has specific gravity ranging from 0.86 to 0.95. It is obtained between 200 to 370 o C. It is used in diesel engine. Diesel engines have found broad use as a result of higher thermodynamic efficiency and fuel efficiency.
13. Which liquid fuel has a wider composition than diesel and used in furnaces of oil fired boiler?
a) Fuel oil
b) Petrol
c) Distillate
d) Alcohol
Answer: a
Explanation: Fuel oil is similar to diesel but has wider composition than diesel. It is used in furnaces of oil fired boilers. Broadly speaking, fuel oil is any liquid fuel that is burned in furnace or boiler for the generation of power, except oil is having a flash point of approximately 42 o C and oils burned in cotton or wool-wick burners.
14. Which is the artificial liquid fuel obtained by fermentation process?
a) Fuel oil
b) Alcohol
c) Distillate
d) Kerosene
Answer: b
Explanation: Alcohol is an artificial fuel obtained from vegetable matter by fermentation process. It is used in many chemical processes. The first four aliphatic alcohols are of interest as fuels because they can be synthesized chemically or biologically. The general chemical formula for alcohol fuel is C n H 2n+1 OH.
15. Which among the following fuels need excess amount of air for complete combustion?
a) Natural fuels
b) Liquid fuels
c) Gaseous fuels
d) Artificial solid fuels
Answer: d
Explanation: Artificial solid fuels need excess amount of air for complete combustion because they have low calorific value compared to liquid fuels and the rate of combustion of solid fuels cannot be easily controlled. They have tendency to form clinkers at high temperatures.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Gaseous Fuels & Nuclear Fuels”.
1. Which fuels are either natural or artificial fuels?
a) Gaseous fuels
b) Solid fuels
c) Liquid fuels
d) Nuclear fuels
Answer: a
Explanation: Gaseous fuels are either natural fuels or artificial fuels. Natural fuels occur in the form of natural gas near oil bearing areas under earth’s surface. Artificial fuels prepared are coal gas coke oven gas, blast furnace gas, producer gas, water gas and mond gas.
2. Which gaseous fuel is found dissolved in petroleum under earth’s surface in oil and gas bearing areas?
a) Natural gas
b) Coal gas
c) Mond gas
d) Producer gas
Answer: a
Explanation: Natural gas is found dissolved in petroleum under earth’s surface in oil and gas bearing areas. It mainly contains 85% Methane (CH 4 ) and hydrogen (H 2 ) along with small percentages of ethane and ethylene. Liquefied petroleum gas is a mixture of propane, butane and other hydrocarbons separated from natural gas. It is stored under pressure in the liquid form. It is used as a domestic fuel and as an automobile fuel.
3. Which gaseous fuel is called as town gas?
a) Natural gas
b) Coke oven gas
c) Coal gas
d) Mond gas
Answer: c
Explanation: Coal gas is called as town gas. It is a by-product obtained during destructive distillation of coal. It mainly contains H 2 , CO, CO 2 , CH 4 and N 2 . It has a calorific value ranging from 21000KJ/m 3 to 25000KJ/m 3 . The gas obtained when coal is heated strongly in the absence of air is called coal gas.
4. Which gaseous fuel is obtained by carbonization of bituminous coal?
a) Blast furnace gas
b) Coal gas
c) Producer gas
d) Coke oven gas
Answer: d
Explanation: Coke oven gas is a fuel gas having a medium calorific value that is produced during the manufacture of metallurgical coke by heating bituminous coal to temperatures of 900 o C to 1000 o C in a chamber from which air is excluded. The main constituents are 50% H 2 , 30% methane and 3% higher hydrocarbons, 7% CO, 3% CO 2 and 7% N 2 . The gas has heating value of about 20,000 KJ/m 3 .
5. Which gaseous fuel has a very low heating value?
a) Blast furnace gas
b) Coke oven gas
c) Water gas
d) Mond gas
Answer: a
Explanation: Blast furnace has a very low heating value. It is obtained as a by-product during blast furnace operation. Due to high percentage of dust content it should be purified before use. It has a calorific value ranging between 3800 KJ/m 3 to 4200 kJ/m 3 . It is used as a fuel in gas engines in steam generation and in steel plants.
6. Which gaseous fuel is obtained by partial combustion of coke?
a) Coke oven gas
b) Producer gas
c) Coal gas
d) Blast furnace gas
Answer: b
Explanation: Producer gas is obtained by partial combustion of coke or coal in the presence of air and steam mixture. It has a calorific value ranging between 5000 kJ/mm 3 to 6800 kJ/mm 3 . It is used in glass melting in Industries and also for power generation.
7. What gaseous Fuel is obtained by passing steam over candescent coke?
a) Producer gas
b) Water gas
c) Coal gas
d) Coke over gas
Answer: b
Explanation: Water gas is obtained by passing steam over candescent coke. It burns with a blue flame and hence it is known as blue water gas. It has calorific value ranging between10500KJ/mm 3 to 2300KJ/mm 3 . It is used in welding and in furnaces.
8. Which gaseous fuel is produced by passing air and steam over waste coal?
a) Blast furnace gas
b) Coal gas
c) Mond gas
d) Coke oven gas
Answer: c
Explanation: Mond gas is gaseous fuel that is produced by passing air and large amount of steam over waste coal at about 650 o C. It has a calorific value of 5800KJ/mm 3 . The mond gas process was designed to convert cheap coal into flammable gas, which was made up of mainly hydrogen while recovering ammonium sulphate. The gas produced was rich in hydrogen and poor in carbon monoxide. Although it could be used for some industrial purposes and power generation, the gas was limited for heating or lighting.
9. Which of the fuels give enormous amount of energy?
a) Gaseous
b) Solid
c) Liquid
d) Nuclear
Answer: d
Explanation: Nuclear fuels result in generation of enormous amount of energy by nuclear reactions namely fission and fusion. In fission reactions, a heavy atom is split by neutrons into two lighter fragments. In fusion reactions, two lighter atomic nuclei are fused together to form a single, heavy nucleus. In order to carry out nuclear reactions fissionable materials are used as fuels.
10. Which is the only nuclear fuel that occurs in nature in abundantly?
a) Plutonium
b) Radium
c) Thorium
d) Uranium
Answer: d
Explanation: Uranium is the only fissionable nuclear fuel occurring in nature. It consists of 99.3% of 92 U 238 , 0.7% 92 U 235 and small traces of 92 U 234 . Out of these isotopes only 92 U 235 is used in fission reaction. Uranium is a very heavy metal which has been used as an abundant source of concentrated energy for 60 years.
11. What do you get when you convert 92 U 238 by conversion process and reacting with neutron?
a) 94 Pu 239
b) 94 Pu 231
c) 94 Pu 241
d) 94 Pu 244
Answer: a
Explanation: Conversion process of uranium 92 U 238
92 U 238 + 0 n 1 -> 92 U 239 + γ – radiation
92 U 239 -> 93 Np 239 + -1 e 0
93 Np 239 -> 94 Pu 239 + -1 e 0
12. What do you get when breeding process is carried out on 90 Th 232 ?
a) 92 U 233
b) 92 U 234
c) 92 U 235
d) 92 U 236
Answer: a
Explanation: When breeding process is performed on 90 Th 232
90 Th 232 + 0 n 1 → 90 Th 233 + γ -radiation
90 Th 233 → 91 Pa 233 + -1 e 0
91 Pa 233 → 92 U 233 + -1 e 0 .
13. Which fuels can breed fissile uranium-233 to be used in various kinds of nuclear reactor?
a) Thorium
b) Neptunium
c) Plutonium
d) Radium
Answer: a
Explanation: Thorium fuels can breed fissile uranium-233 to be used in various kinds of nuclear reactor. The use of thorium as a new primary energy source has been tantalizing prospects for many years. It is fertile rather than fissile, and can only be used as a fuel in conjunction with a fissile material.
14. Which two nuclear fuels are produced artificially?
a) 92 Pu 239 and 92 U 233
b) 92 Pu 244 and 92 U 234
c) 92 Pu 241 and 92 U 235
d) 92 Pu 242 and 92 U 236
Answer: a
Explanation: Plutonium 92 Pu 239 and uranium 92 U 233 are the fissionable materials produced artificially from 92 U 238 and 90 Th 232 respectively. Uranium-238 and thorium 232 are available in nature. They are known as fertile materials. These fertile materials when placed close to 92 U 235 in a reactor absorb the emitted neutrons to produce fissionable materials as follows.
15. What helps in converting uranium into fuel?
a) Breeder
b) Vitrification
c) Fuel fabricator
d) Enrichment plant
Answer: c
Explanation: Fuel fabrication plants help in converting enriched uranium into fuel for nuclear reactors. For light water reactors, uranium is received from an enrichment plant in solid form. It is then converted into uranium dioxide powder. This powder is passed into pellets and packed into fuel assemblies.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Combustion of Fuels”.
1. The process of burning fuels in the presence of oxygen is called _________
a) Induction
b) Ignition
c) Condensation
d) Combustion
Answer: d
Explanation: The process of burning fuels in the presence of oxygen is called combustion. Due to the presence of combustible elements like carbon , hydrogen and sulfur , fuels burn in presence of oxygen and generate heat from the fuels.
2. The minimum temperature at which a substance begins to burn is called ________
a) Fire point temperature
b) Auto ignition
c) Ignition temperature
d) Flash point temperature
Answer: c
Explanation: The minimum temperature at which a substance begins to burn is called ignition temperature. No substance can catch fire unless it is heated up to a certain minimum temperature. The ignition of every substance is definite. For example, the ignition temperature of white phosphorous is 35°C. It means, white phosphorous starts burning only if it is heated up to 35°C.
3. The substance which helps in combustion of fuels is called _________
a) Igniter
b) Flammables
c) Supporter
d) Inflammables
Answer: c
Explanation: The substance which helps in combustion of fuels is called supporter fuels/combustible elements. For example, oxygen is a supporter of combustion because in the absence of oxygen fuels cannot burn.
4. What is necessary for complete combustion of fuels?
a) There should be no water content in the fuel
b) Sufficient amount of air is required
c) High quantity of fuel
d) Open space to burn easily
Answer: b
Explanation: For complete combustion of fuels, it is necessary to supply sufficient amount of air. If air supplied is not sufficient then combustion will be incomplete. This means carbon in the fuel burns to produce carbon monoxide instead of carbon dioxide (CO 2 ), and thus reducing the amount of oxygen required and amount of heat generated.
5. C + O 2 →_____
a) CO
b) CO 2
c) CO 3
d) 2CO
Answer: b
Explanation: Based on molecular weight, 12kg of carbon combines with 32kg of oxygen forming 44kg of carbon dioxide.
i.e., 12kg of C + 32 kg of O 2 => 44kg of CO 2
1kg of C + 8/3kg of O 2 => 11/3kg of CO 2
Reaction type: synthesis.
6. C + O 2 => _______
a) CO
b) 2CO 2
c) 2CO
d) CO 3
Answer: c
Explanation: Balanced equation: 2C + O 2 => 2CO [Synthesis reaction] Oxygen is left in excess, based on the molecular weight, 24kg of carbon combines with 32kg of oxygen forming 56kg of carbon monoxide
24kg of C + 32kg of O 2 => 56kg of CO
1kg of C + 4/3kg of O 2 => 7/3kg of CO.
7. CO + O 2 => _______
a) 2CO 2
b) CO 2
c) CO
d) CO 3
Answer: a
Explanation: Based on molecular weight, 56kg of carbon monoxide combines with 32kg of oxygen forming 88kg of CO 2
Balanced equation: 2CO + O 2 => 2CO 2
56kg of CO + 32kg of O 2 => 88kg of CO 2
1kg of CO + 4/7kg of O 2 => 11/7kg of CO 2 .
8. H 2 + O 2 => _____
a) H 2 O
b) OH
c) H 3 O
d) 2H 2 O
Answer: d
Explanation: Based on molecular weight, 32kg of sulfur combines with 32kg of oxygen forming 36kg of water.
Balanced equation: 2H 2 + O 2 => 2H 2 O
4kg of H 2 + 32kg of O 2 => 36kg of H 2 O
1kg of H 2 + 8kg of O 2 => 9kg of H 2 O.
9. S + O 2 => ______
a) SO 3
b) SO 2
c) S 2-
d) 2SO 2
Answer: b
Explanation: Based on molecular weight, 32 kg of sulfur combines with 32 kg of oxygen forming 64 kg of SO 2
S + O 2 => SO 2
32 kg of S + 3 2 kg of O 2 => 64 kg of SO 2
1 kg of S + 1 kg of O 2 => 2 kg of SO 2 .
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Calorific Value of Fuels – 1”.
1. The amount of heat liberated by complete combustion of unit quantity of fuel is known as ________
a) Agitation
b) Combustion
c) Calorific value
d) Thermogenesis
Answer: c
Explanation: when fuels are burnt, heat is produced. It can also be defined as the amount of heat produced on complete burning of 1gm of fuel. SI unit of calorific value is kJ/g. The chemical reaction is typically hydrocarbon or other organic molecule reacting with oxygen to form carbon dioxide and water and release heat.
2. What is the significance of calorific value?
a) Helps in deciding which fuel is good
b) Helps in locating fuel
c) Helps in deciding ignition temperature
d) Helps in deciding fire point
Answer: a
Explanation: The different fuels have different calorific values, i.e. different fuels produce different amount of heat in heat on burning. The calorific value of fuel helps us to decide that which fuel is good for us. This is done by comparing the calorific values of fuels with each other. Usually, a fuel having higher calorific value is considered to be a good fuel.
3. Which gas has the highest calorific value among given option?
a) Oxygen
b) Helium
c) Hydrogen
d) Nitrogen
Answer: c
Explanation: Hydrogen gas has the highest calorific value of 150KJ/g among all. So, hydrogen gas is considered is considered to be an extremely good fuel. However, hydrogen gas is not used as a fuel in homes and industries. Reason is hydrogen is highly combustible and it burns with explosion when lighted, its transportation from place to place is very difficult, and the cost of production of hydrogen is very high.
4. How much percent of hydrogen gas does methane contain?
a) 25%
b) 50%
c) 68%
d) 85%
Answer: a
Explanation: Methane contains 25% of hydrogen. Since the calorific value of fuels depends on the percentage of hydrogen present in them. So the fuels which have higher percentage of hydrogen will have higher calorific value as compared to those fuels which have lower percentage of hydrogen.
5. Which calorimeter is used to find calorific values of solid and liquid fuels?
a) Boy’s calorimeter
b) Bomb calorimeter
c) Junker’s calorimeter
d) Calvet-type calorimeter
Answer: b
Explanation: The calorific value of solid of solid and liquid fuel is defined as the amount of heat liberated by complete combustion of unit mass of fuel. In SI unit s it is expressed in kJ/kg. A bomb calorimeter is a type of constant volume calorimeter used in measuring heat of combustion of particular reaction. Bomb calorimeters have to withstand the large pressure within the calorimeter as the reaction is being measured.
6. Which calorimeter is used to find calorific values of gaseous fuels?
a) Bomb calorimeter
b) Junker calorimeter
c) Adiabatic calorimeter
d) Isothermal titration calorimeter
Answer: b
Explanation: The calorific values of gaseous fuel are defined as the amount of heat liberated by complete combustion of unit volume of fuel. SI unit is KJ/m 3 . This calorimeter works on principle of burning of a known volume of gas an imparting the heat with maximum efficiency to steadily flowing water and finding out the rise in temperature of a measured volume of water.
7. The calorific value of all organic compounds has the sign corresponding to a ________
a) Exothermic reaction
b) Endothermic reaction
c) Single displacement reaction
d) Synthesis reaction
Answer: a
Explanation: The calorific value of all organic compounds has the sign corresponding to an exothermic reaction. Because the double bond in molecular oxygen is much weaker than other double bonds or pairs of single bonds, particularly those in combustion products carbon dioxide and water, conversion of the weak bonds in o 2 to the stronger bonds in CO 2 and H 2 O releases energy as heat.
8. What value of a substance, usually a fuel or food is the amount of heat released during the combustion?
a) Energy value
b) Flash point value
c) Fire point value
d) Auto ignition
Answer: a
Explanation: Energy value of a substance, usually a fuel or food is the amount of heat released during the combustion of a specified amount of it. The energy value is characteristic for each substance. It is measured in units of energy per unit of the substance, usually mass, such as Kj/Kg, KJ/mol, and kcal/kg.
9. What accounts for the presence of water in the exhaust leaving as vapor?
a) Gross calorific value
b) Flash point value
c) Ignition temperature value
d) Net calorific value
Answer: a
Explanation: Gross heating value accounts for water in the exhaust leaving as vapor, and includes liquid water in the fuel prior to combustion. This value is important for fuels like wood and coal, which will usually contain some amount of water prior to burning.
10. What is the factor on which, difference between the two heating values of fuel depends on?
a) Physical properties
b) Reactants
c) Chemical composition
d) Products
Answer: c
Explanation: The difference between the two heating values depends on the chemical composition of the fuel. In the case of pure carbon or carbon monoxide, the two heating values are almost identical, the difference being the sensible heat content of carbon dioxide between 150 o C to 25 o C.
This set of Energy Engineering Interview Questions and Answers for freshers focuses on “Calorific Value of Fuels – 2”.
1. Which is the common method to relate higher calorific value to lower calorific value?
a) HCV = LCV + H V (n H 2 O, out / n fuel, in )
b) LCV = HCV + H V (n H 2 O, out / n fuel, in )
c) HCV = LCV + H V (n fuel, in / n H 2 O, out )
d) LCV = HCV + H V (n fuel, in / n H 2 O, out )
Answer: a
Explanation: H V – heat vaporization of water.
n H 2 O, out – moles of water vaporized.
n fuel, in – number of moles of fuel combusted.
High calorific value is equal to low calorific value plus, product of heat of vaporization of water and moles of water vaporized by moles of fuel combusted.
2. Based on what basis are fuels compared?
a) Fire point value
b) High calorific value
c) Flash point value
d) Low calorific value
Answer: d
Explanation: On basis of low calorific value the fuels are compared. Low calorific value is the amount of heat evolved when a unit weight of fuel is completely burnt and water vapor leaves with combustion products.
3. Which value is determined by bringing all products of combustion back to original pre-combustion temperature?
a) Higher calorific value
b) Low calorific value
c) Flash point value
d) Fire point value
Answer: a
Explanation: High calorific value is determined, as all fuels contain hydrogen; they produce water vapor during combustion. When the products of combustion containing water vapor are cooled back to initial temperature, then all water vapors formed condense and evolve latent heat. This adds up to the heat liberated by burning the fuel, producing maximum amount of heat per kg of fuel. This heat is known as the higher calorific value of fuel, and it is denoted by HCV.
4. Which calorific value is same as the thermodynamic heat of combustion?
a) Net calorific value
b) Flash point value
c) Gross calorific value
d) Fire point value
Answer: d
Explanation: Gross calorific value is as same as the thermodynamic heat of combustion since the enthalpy change for the reaction assumes a common temperature of the compounds before and after combustion, in which case the water produced by combustion is condensed to a liquid, hence yielding its latent heat of vaporization.
5. Which value is determined by subtracting the heat of vaporization of the water from the higher heating value?
a) Gross calorific value
b) Net calorific value
c) Ignition temperature
d) Fire point temperature
Answer: b
Explanation: Net calorific value determined. In most of the combustion processes, the products of combustion cannot be cooled to its initial temperature. Thus water vapors don’t condense and hence the latent heat of water vapor is lost to the atmosphere. The resultant heat liberated by the fuel which excludes the latent heat of evaporation of water vapors is known as lower calorific value of fuel.
6. Which formula is used to determine higher calorific value of fuel?
a) Rayleigh’s formula
b) Lamme’s equation
c) Dulongs’s formula
d) Cauchy’s formula
Answer: c
Explanation: Higher calorific value of the fuel can be determined by using Dulongs’s formula. Let C, H, O and S represent the percentage by weight of carbon, carbon, oxygen and sulfur respectively.
HCV = 1/100 [33900 + 144000) + 9295 S] kJ/Kg
This formula gives gross heating value in terms of the weight fractions of carbon, hydrogen, oxygen and sulfur from the ultimate analysis.
7. Lower calorific value can be determined by equation:
a) LCV = HCV – m*2466
b) LCV = HCV +
c) LCV = HCV –
d) LCV = HCV +
Answer: a
Explanation: Lower calorific value can be determined equation [LCV = HCV – m*2466]. The latent heat lost to the atmosphere depends on evaporation pressure and the amount of water vapors formed. Due to difficulty in measuring the evaporation pressure, it is assumed that evaporation takes place at a saturation temperature of 15°C. The latent heat corresponding to this saturation is 2466 kl/kg.
m = mass of water vapour formed per kg of fuel burnt.
8. Which fuel has higher calorific value among given fuels?
a) Natural gas
b) Gasoline
c) Diesel
d) Fuel oil
Answer: b
Explanation: Gasoline also called as petrol, has the highest calorific value. Gasoline is a transparent petroleum derived liquid that is used primarily as a fuel in internal combustion engines. It consists of mostly of organic compounds obtained by the fractional distillation of petroleum, enhanced with variety of additives.
9. What is amount of minimum air required per kg of liquid fuel for complete combustion using carbon, oxygen, hydrogen and sulfur?
a) 1/23 [8/3 C + 8) + S]
b) 1/100 [8/3 C + 8) + S]
c) 1/100 [8/3 C + 8)]
d) 1/23 [8/3 C + 8)]
Answer: a
Explanation: Let C, H, O and S represent percentage by mass of carbon, Hydrogen (H 2 ), oxygen and sulfur respectively.
The mass of oxygen required for complete combustion of fuel is given by,
= 1/100 [8/3 C + 8H – O + S]
= 1/100 [8/3C + 8) + S]
As air contains 23% of oxygen by mass, minimum air required for burning one kg of liquid fuel completely is given by,
Min. air required = 1/100 [8/3 C + 8) + S] 100/23
= 1/23 [8/3 C + 8 ) + S].
10. What is minimum amount of air required per m 3 of gaseous fuel for complete combustion?
a) 1/21 [(H 2 /2) + + 2CH 4 + 3C 2 H 4 ] m 3 /m 3 of fuel
b) 1/100 [(H 2 /2) + + 2CH 4 + 3C 2 H 4 ] m 3 /m 3 of fuel
c) 1/21 [(H 2 /2) + + 3C 2 H 4 ] m 3 /m 3 of fuel
d) 1/100 [(H 2 /2) + + 3C 2 H 4 ] m 3 /m 3 of fuel
Answer: a
Explanation: Volumetric analysis of fuels hydrogen, carbon monoxide, methane, ethane, carbon dioxide and nitrogen is done and required minimum amount of oxygen is found for one m 3 of gaseous fuel:
O 2 required/m 3 of fuel = 1/100[(H 2 /2) + + 2CH 4 + 3C 2 H 4 ] m 3
As atmospheric air contains 21% of O 2 by volume, minimum air required t burn one m 3 of gaseous fuel is given by,
Minimum volume of air required (cm 3 /m 3 of fuel):
= 1/100 [(H 2 /2) + + 2CH 4 + 3C 2 H 4 ] 100/21
= 1/21 [(H 2 /2) + + 2CH 4 + 3C 2 H 4 ] m 3 /m 3 of fuel.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Principle of Automatic Control of Combustion”.
1. What is the basis on principle of automatic control of combustion is determined?
energy-engineering-questions-answers-principle-automatic-control-combustion-q1toq-8
a) Control of fuel supply to the boiler
b) Speed of rotation of fans
c) Control of combustion
d) Control of steam pressure
Answer: c
Explanation: The principle of automatic control of combustion is derived from the control of combustion. In order to ensure sufficient amount of steam generation at the requisite pressure and to maintain correct proportion of fuel and air in a furnace for complete combustion, control of combustion in the furnace is very much essential.
2. What quantities need to maintained/regulated for effective control of combustion?
energy-engineering-questions-answers-principle-automatic-control-combustion-q1toq-8
a) Induced draught and forced draught fans pressure
b) Air and steam gauge pressure
c) Fuel flowing out of stoker
d) Air and fuel supply
Answer: d
Explanation: Combustion can be effectively controlled by regulating the quantities of air and fuel or both. Control of combustion can be by manual or automatic means. Automatic control of combustion is used to distribute the load evenly on the boiler as per the changing demand.
3. What is necessary to ensure products of combustion flow into the chimney?
energy-engineering-questions-answers-principle-automatic-control-combustion-q1toq-8
a) Air speed
b) Draft in the chimney
c) Differential gas pressure
d) Swirl flow of exhaust air
Answer: c
Explanation: In order to ensure products of combustion flow into the chimney at proper speed, it is essential to regulate differential gas pressure in the furnace. In case of automatic control, the controlling devices operate based on the change in pressure of steam.
4. When does automatic control system of combustion come into operation?
energy-engineering-questions-answers-principle-automatic-control-combustion-q1toq-8
a) When there is no fluctuation in furnace draft
b) When there is variation in steam flow rate
c) When the draft connection is clogged
d) When there is minimal amount of air supply
Answer: b
Explanation: Automatic control combustion system comes into action when there is variation in steam flow rate also when there is fluctuation in steam pressure and furnace draft. It is safer compared to manual control system and saves manual labour and time.
5. Which is the component that maintains forces in whole automatic combustion control system?
energy-engineering-questions-answers-principle-automatic-control-combustion-q1toq-8
a) Steam pressure gauge
b) Fan vanes
c) Master controller
d) Relay 1 & 2
Answer: c
Explanation: Master controller is the component that maintains all the forces in whole system. The actions of primary forces are magnified through the master controller which in turn operates the concerned elements through electric, hydraulic and pneumatic system. The master control makes variation depending on steam pressure level.
6. When does master controller comes into action?
energy-engineering-questions-answers-principle-automatic-control-combustion-q1toq-8
a) When there is variation in steam flow rate
b) When there is variation in fuel supply
c) When there is variation in steam pressure
d) When there is variation in draught fans
Answer: c
Explanation: The master controller comes into action when there is variation in steam pressure and it goes down below the required level. This activates the servo motor coupled to the vanes of induced draught fan which opens the air damper slightly. Simultaneously the secondary fan air damper also opens proportionately.
7. When does relay’s 1 and 2 come into operation?
energy-engineering-questions-answers-principle-automatic-control-combustion-q1toq-8
a) When there are changes in steam pressure
b) When there is change in forced draught
c) When there is change in steam flow rate
d) When there is change in induced draught
Answer: d
Explanation: When there are variation made in induced draught by air dampers opening due to coupling of motor that’s when relay 1 and 2 comes into operation. Relay 1 operates and adjusts the forced draught fan vanes till stability is restored in the combustion chamber. This result in an increased flow rate of air through the passage P. Due to increased flow rate, relay 2 is actuated which speeds up the stoker motor to supply extra fuel.
8. What is the purpose of Automatic combustion control system?
energy-engineering-questions-answers-principle-automatic-control-combustion-q1toq-8
a) To get constant steam pressure
b) To maintain steady state combustion
c) To get constant steam output
d) To save the time and manual labour
Answer: b
Explanation: The automatic combustion control system provides the effective prevention of the environmental pollution and steady combustion condition to get a constant steam output. But few factors prevent steady combustion condition such as unbalanced combustion air and the movement of the burn-out position in the incinerator.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Fuel Burning”.
1. What is the most important factor that is essential for economical working of a power plant?
a) Abundant fuel input
b) Rotational speed of turbines
c) Efficient transfer of heat energy to water
d) Proper maintenance Ash and other waste handling systems
Answer: c
Explanation: The economical working of power plant depends upon factors such as efficient transfer of heat energy to water for generation of steam and efficient combustion of fuel in combustion chamber. Many improvements have been made in design of the furnace to increase the rate of combustion.
2. What type of reaction is burning?
a) Endothermic reaction
b) Exothermic reaction
c) Synthesis reaction
d) Decomposition reaction
Answer: b
Explanation: Burning is an exothermic reaction. A fuel is a store of chemical energy that we convert into useful energy to our purposes. For example, we can use the energy stored in natural gas to cook our food. To release this energy, we usually burn the fuel. Burning is a chemical reaction in which the fuel reacts with oxygen gas in air and gives out energy in terms of heat. We call this type of reaction as exothermic reaction.
3. Which type of furnace cannot be used in the modern era plants?
a) Hand fired furnace
b) Electric arc furnace
c) Solar furnace
d) Central warm air furnace
Answer: a
Explanation: A hand fired furnace is simple in design, but it cannot be used in modern power plants because of its lower combustion efficiency. It does not respond quickly to fluctuating loads and control of draught is very difficult.
4. How much pounds of CO 2 is emitted per million BTU when coal is burnt?
a) 139
b) 117
c) 157
d) 205
Answer: d
Explanation: 205 million BTU is the pounds of CO 2 that is emitted when coal is burnt. The amount of CO 2 produced when a fuel is burned is a function of carbon content of fuel. The heat content, or the amount of energy produced when a fuel is burned, is mainly determined by the carbon and hydrogen content of the fuel.
5. A combustion equipment is a component of ____________
a) Turbine
b) Steam generator
c) Flue gas system
d) Ash handling system
Answer: b
Explanation: A combustion equipment is a component of steam generator. It receives the fuel and air proportionals to each other and to the boiler steam demand, mix, ignites and performs other function such as distillation of volatile matter of coal.
6. What was the reason for the poor efficiency of boiler in earlier time?
a) Boilers were set close to grates
b) Poor design of exhaust system
c) Impurities contamination the fuels
d) Lack of proper maintenance
Answer: a
Explanation: In earlier times boilers were set very close to the grates and combustion space was limited and hence resulted in smoke and poor efficiency. Later, furnaces were made larger and the boilers were set at higher level above the grates. The hand fired furnace with large combustion space was used to burn a wide variety of coals.
7. Which was first combustion system used for solid fuels?
a) Firing stoker
b) Tangential stoker
c) Grate firing
d) Pulverized fuel firing
Answer: c
Explanation: Grate firing was the first combustion system used for solid fuels. It now is used mainly for burning waste and biomass, but also for smaller coal furnaces. Fuel fired per grate area is 1-2 MW/m 2 , ad maximum grate area is 100m 2 .
8. The amount of fuel burned depends on ____________
a) Design of burner
b) Depends on air inlet and exhaust system
c) Depends on bed movement velocity
d) Depends on amount of supply of combustion supportive air
Answer: c
Explanation: The amount of fuel burned depends on the amount of fuel burned and on the bed velocity movement. The grate area is the total area of grate . The large the grate area, the more fuel can be burned per hour.
9. Which device is used for feeding the fuel automatically to boiler or furnace in power plants?
a) Relay
b) Mechanical stoker
c) Master controller
d) Feed pump
Answer: b
Explanation: Mechanical stoker is the device which automatically feeds a solid fuel into combustion chamber of a boiler or furnace, and provides air for the proper combustion; may include a means for automatically removing solid products of combustion.
10. What is used in case, to throw coal into furnace that is set off far from the supply?
a) Speed convey belt
b) Bucket chain
c) Paddle
d) Steam jet
Answer: d
Explanation: Steam jet from the boiler or a mechanical catapult may also be used to throw coal into far reach of the furnace. The mechanical means used in the system depend on the design, combinations of screw feed, the conveyor belt, the bucket chain, the paddle and the ram.
11. Where exactly are mechanical stokers used?
a) In transportation of fuels
b) In small capacity plants
c) In large capacity plants
d) For domestic usage
Answer: c
Explanation: Mechanical stokers are usually used in large and medium capacity plants. Mechanical stokers are used to fire almost all kinds of coal. This produces less smoke than hand firing. A stoker consists of a power feeding machine and a grate.
12. Which type of stokers has more demand in the market?
a) Spreader stoker
b) Vibrating stoker
c) Travelling stoker
d) Underfeed stoker system
Answer: a
Explanation: Spreader stoker systems are receiving the greatest interest and sales in the market. Depending upon the method of introducing the coal into furnace, stokers are mainly classified into spreader stokers, underfeed stokers, vibrating grate stokers and travelling grate stokers.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Principle of Stoker”.
1. How is the coal fed to the grate in over feed system?
a) Above the point of air admission
b) Between the beds of incandescent coke and green coal
c) Above the ash bed
d) Between the point of air admission
Answer: a
Explanation: The coal is fed on the grate above the point of air admission. The pressurized air coming from forced draught fan enters under the bottom of the grate. The air passing through the grate is heated by absorbing the heat from the ash and grates itself. Due to this the ash and grate are cooled.
2. The amount of CO 2 formed in overfeed system entirely depends on ___________
a) Amount of ash produced
b) Carbon content in fuel
c) Rate of air supply
d) Intensity of process
Answer: c
Explanation: The rate of carbon-dioxide entirely depends on the rate of air supply. When the hot air after cooling the ash passes to incandescent coke bed, here the O 2 reacts with C to form CO 2 . Generally for fuel bed of 800mm depth all the O 2 in the air is consumed in the incandescent region.
3. Which is the zone where the water vapors carried in air reacts with carbon in over-feed system?
a) Green coal bed zone
b) Incandescent zone
c) Combustion zone
d) At the ash pit
Answer: b
Explanation: The water vapor carried with air reacts with Carbon in incandescent zone and forms CO, CO 2 , and H 2 . Part of CO 2 formed reacts with air C passing through incandescent zone and converts into CO. The gases leaving the incandescent region of fuel bed consist of N 2 , CO 2 , CO, H 2 and H 2 O.
4. How is volatile matter of raw coal is lost in the overfeed system?
a) Condensation
b) Distillation
c) Combustion
d) Evaporation
Answer: b
Explanation: Raw coal that is continuously supplied on the surface of the bed loses it volatile matter by distillation in this zone. The required for the distillation of coal is given by incandescent coke below the fresh fuel, hot gases diffusing through the surface of the bed and hot gases and flame in the furnace above.
5. Where does the ignition zone lie in overfeed system?
a) Below the raw fuel undergoing distillation
b) Below the combustion zone
c) In between coke bed and flame zone
d) Between coke bed and green coal bed
Answer: a
Explanation: The ignition zone lies directly below the raw fuel undergoing distillation. The gases leaving the upper surface of the fuel bed contain combustible volatile matter formed from the raw fuel N 2 , CO 2 , O 2 , H 2 O and CO if the burning is incomplete.
6. Why is secondary air supplied in overfeed system?
a) To burn the unburnt gases
b) To maintain constant heat intensity
c) To completely remove water vapors formed due to primary air supply
d) To create distillation process for the raw coal supplied
Answer: a
Explanation: Additional secondary air is supplied at the top of the bed to burn the remaining combustible gases (volatile matter+CO+H 2 ). The secondary air is supplied at very high speed to create turbulence for complete combustion of unburnt gases.
7. Why does burnt gases with content of N 2 , CO 2 , H 2 , O 2 and H 2 O re-enter the boiler in overfeed system?
a) To dismiss the ash content in the gases formed
b) Due to incomplete burning
c) For complete removal of moisture
d) To complete the burn the coal
Answer: b
Explanation: The burnt gases re-enter the boiler containing N 2 , CO 2 , O 2 , H 2 O and CO if the burning is incomplete. During incandescence, the fuel is continuously loses its carbon by oxidation until only the ash remains.
8. In which direction does fuel, coke and ash in fuel bed move with respect to air and gases in overfeed system?
a) Upward direction
b) Same direction
c) Opposite direction
d) Downward direction
Answer: c
Explanation: Fuel, coke and ash in the fuel bed move in the direction opposite to that of air and gases. The primary air entering from the bottom cools the ash until it finally rests in a plane immediately adjacent to the grate.
9. In which direction does fuel and air in under-feed system move?
a) Opposite
b) Across
c) Same direction
d) Counter direction
Answer: c
Explanation: In under feed type of stokers, the fuel and air move in the same direction. In this stoker air after passing through the holes in the grate comes in contact with the raw coal. As air diffuses through the bed of raw coal, it mixes with the volatile matter generated by the raw coal.
10. Which is the process from which heat for distillation comes, in under feed system?
a) Conduction
b) Combustion
c) Synthesis reaction
d) Circulation of hot air gases
Answer: a
Explanation: The heat for the distillation comes by conduction from the mass of incandescent fuel bed existing above the raw coal. The air mixes with the volatile matter and passes through the ignition zone and then enters into the region of incandescent coke.
11. Which reaction differs over feed and under feed system?
a) Changes occurring in physical properties of the system
b) Breaking of molecular structure
c) Changes in chemical composition
d) Existence of volatile matter
Answer: b
Explanation: The reactions which take place in the incandescent zone of under-feed stoker is exactly same as in the incandescent zone of over feed stoker except some breaking of molecular structure of volatile matter. Part of the broken volatile matter reacts with the oxygen of air.
12. What is the purpose of secondary fan’s air in under feed system?
a) To support gases coming out of fuel bed
b) To clear the ash from the upper beds
c) To maintain constant pressure in system
d) To support combustion of system
Answer: a
Explanation: The gases coming out of raw fuel bed pass through a region of incandescent ash on the surface of the fuel and finally discharged to the furnace. As the gases coming out of fuel bed also contain combustible matter the supply of secondary air is required in this case. The ash left at the bottom of the stoker is at a higher temperature than the over feed stoker.
13. What is the significance of rate at which air is supplied in the under feed system?
a) Increase depth of incandescent zone
b) Pushes up ignition zone
c) Burns fuel for long time
d) Supports combustion
Answer: a
Explanation: The rate of air supply has marked effect on the speed of ignition in case of under feed burning as the rising air cools the raw fuel prior to ignition. At low rate of air fuel, the heat flow by conduction from the incandescent fuel bed downward is faster than the removal of heat by air. This pushes the ignition plane down below the bed surface and creates a maximum depth of incandescent zone.
14. Which type of coal is used in the under feed system?
a) Anthracite coal
b) Bituminous coal
c) Briquette coal
d) Pulverized coal
Answer: b
Explanation: The under feed method uses bituminous coals which have high volatile matter. The volatile matter gets heated to a high temperature as it passes through incandescent region of coal. The volatile matter being at a high temperature before entering the furnace burns quickly when mixed with secondary air.
15. Why does over feed burning system takes longer time for complete burning?
a) The volatile matter will be cooler at initial
b) Due to the presence of dust and ash
c) The effect of design of system
d) Effects of air fuels on the system
Answer: a
Explanation: In case of over-feed burning, the volatile matter will be considerably cooler than the furnace gases and therefore it requires longer time for complete burning and also the air passes though incandescent zone and then enters ignition zone. This may create a tendency to form smoke.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Type of Stokers – 1”.
1. In what aspect does chain gate travelling stoker and bar grate travelling stoker differ?
a) Differ in supply of reactants
b) Differ in process of operation
c) Differ in construction
d) Differ in terms of feeding mechanism
Answer: c
Explanation: The travelling grate stoker may be of chain grate type or bar grate type. These two, differ only in the construction of grate. The chain stoker employs an endless chain which is constructed to form a support for the fuel bed. The traveling grate stoker consists of grate bars carried by steel chains.
2. How does the chain run in travelling grate stoker?
a) Railings
b) Sprockets
c) Rim
d) Shaft
Answer: b
Explanation: The chain travels over two sprockets. In both chain type and in bar type stokes. One sprocket is placed at the front end and other sprocket is placed at the rear end of the furnace. The front sprocket is connected to a variable speed driving mechanism.
3. In what way is the supply coal/fuel is done in travelling grate stoker?
a) Screw conveyor
b) Tuyere
c) Reciprocating mechanism
d) Gravity hopper
Answer: d
Explanation: The coal is fed by gravity from a hopper located in front of the stoker. The depth of fuel on the grate is regulated by hand adjusted gate. The speed of the grate varies at the rate at which the coal is fed to the furnace.
4. Automatic combustion control in travelling stoker regulates speed of grate to maintain ____________
a) Steam generation
b) Air flow
c) Fuel supply
d) Conveyor speed
Answer: a
Explanation: The combustion control automatically regulates the speed of the grate to maintain the required steam generation rate. The ash containing a small amount of combustible material is carried over the rear end of the stoker and deposited in the ash pit.
5. Depending on what factor are the air ducts opened and closed in travelling grate stoker?
a) On the type of grate used
b) On the speed that is attained
c) On the type of coal used
d) Depending on intensity of boiler
Answer: c
Explanation: Depending on type of coal burned, the grate has air openings in the range of 20-40 percent of the total area. The air supply to different parts of the stoker is regulated to meet the changing demand through these sections.
6. What does both primary and secondary air ports combined provide in travelling grate stoker?
a) Pressure
b) Evaluating temperature
c) Turbulence
d) Heat intensity
Answer: c
Explanation: The air required for the combustion is supplied through the air inlets situated the below the grate. The secondary air is supplied through the openings provided in the furnace will be above the grate. The combination of primary air and over fire supplied provide turbulence required for rapid combustion.
7. Why is it necessary to control burning in different areas of travelling grate stoker?
a) Minimize the coke carried into ash pit
b) To avoid the smoke
c) To form a maintain temperature throughout the stoker
d) To get the proper efficiency
Answer: a
Explanation: The operator controls rate of burning in different zones to minimize the coke carried over to ash pit. The coal supplied to the grate is regulated either by varying depth of coal on the grate with the help of grate valve and by varying the rate of grate travel.
8. Which type of coal fuel is avoided in travelling grate stoker?
a) Anthracite coal
b) Briquette
c) Pulverized coal
d) Caking bituminous
Answer: d
Explanation: Any type of fuel except caking bituminous coal can be used with travelling grate stoker because of the formation of large percentage of fines resulting in increased carbon loss. The rate of burning of fuel in this stoker is 200 to 300kg/m 2 per hour when forced draught is used.
9. What type of stoker is spreader/sprinkler stoker?
a) Over feed
b) Single retort
c) Multi retort
d) Under feed
Answer: a
Explanation: Spreader stoker is an over feed type of stoker. The coal burned on this stoker remains partly in suspension and partly on the grate. The spreader stoker consists of variable feeding device, a mechanism for throwing the coal uniformly on the grate and suitable openings for admitting the air.
10. Where is the coal feeding mechanism located in spreader type stoker?
a) Above the grate
b) Right side of the grate
c) Left side of the grate
d) Below the grate
Answer: a
Explanation: The coal feeding and distribution mechanism is located in the front above the grate of a spreader stoker. A portion of coal is supplied containing fine particles fine particles of coal burns in suspension and remaining falls to the grate.
This set of Energy Engineering Questions and Answers for Experienced people focuses on “Type of Stokers – 2”.
1. Where is the place at which the volatile matter and fine particles burnt in the spreader stoker?
a) Over the grate
b) In steam gauge
c) In the suspension
d) In the coal bed
Answer: c
Explanation: The air supplied by the forced draught fan enters the furnace through the openings provided in the grate. A portion of this air is used to burn the fuel on the grate and remaining air is utilized to burn the volatile matter and fine particles in suspension.
2. From where is the over fire or secondary air is supplied through in the sprinkler stoker?
a) Air duct
b) Nozzle
c) Air damper
d) Tuyere’s
Answer: b
Explanation: Over fire or secondary air is supplied through nozzle. The secondary air creates high turbulence and completes the combustion of volatile matter and fine particles of the coal. The unburnt coal and ash are deposited on the grate which should be removed periodically.
3. In which manner is the coal supplied from feeder to spreader in spreader stoker?
a) Feeding in alternate bulks
b) Feeding at regular intervals
c) Feeding in continuous stream
d) Feeding whenever necessary
Answer: c
Explanation: The feeder is a slow speed rotating drum on which large numbers of small blades are mounted. It supplies coal to the spreaders in continuous stream. The speed of the feeder can be adjusted as per the load on plant. The feeders are operated with variable speed drive to control the combustion as per the requirement. The feeders may be reciprocating ram, endless belt or spiral worm.
4. Why are the blades of shaft in spreader stoker twisted?
a) For supporting combustion by supplying more amount of air
b) To draw in large amount of coal
c) For uniform distribution of coal
d) To restrict the supply of coal
Answer: c
Explanation: Spreader consists of rapidly rotating shaft carrying blades. These blades are twisted to provide uniform distribution of the coal over the grate. The fast rotating blades hit the coal particles coming from the feeder and throw into the furnace. The distribution of coal over the grate depends on the rotating speed of the spreader and on the size of the coal.
5. How much capacity of heat is possible to produce by the travelling grate stoker?
a) 80 * 10 6 kJ/m 2 .hr
b) 40 * 10 6 kJ/m 2 .hr
c) 25 * 10 6 kJ/m 2 .hr
d) 65 * 10 6 kJ/m 2 .hr
Answer: a
Explanation: The spreader stoker has wide applications with respect to the fuels used as well as to the boiler sizes. A wide variety and poor quality coal can be burnt efficiently with this type of stoker. This type of stoker can be used for boiler capacities of 80 tons to 150 tons of steam per hour. The heat release rate of 80 * 10 6 kJ/m 2 hr is possible with travelling grate.
6. Which mechanism is used to supply coal in the single retort stoker?
a) Hopper
b) Chain bucket
c) Screw conveyor
d) Air blowers
Answer: c
Explanation: The fuel is placed in the large hopper on the front of the furnace. Then it is further fed by reciprocating ram or screw conveyor into the bottom of the horizontal trough. The ash formed after burning of coal is collected at other end.
7. What are provided for the supply of air in single retort stoker?
a) Nozzles
b) Air ducts
c) Tuyere’s
d) Air blowers
Answer: c
Explanation: The air is supplied through the tuyeres provided along the upper edge of the grate. The ash and clinkers are collected on the ash plate provided with dumping arrangement. The coal feeding capacity of a single retort stoker varies from 100 to 2000 kg per hour.
8. Which mechanism is used for the uniform distribution of the coal in multi retort stoker?
a) Reciprocating ram
b) Nozzle
c) Screw conveyor
d) Steam jet blowers
Answer: a
Explanation: the multi retort stoker consists of a series of alternate retorts and tuyere boxes for supply of air. Each retort is fitted with a reciprocating ram for feeding and pusher plates for the uniform distribution of coal. The coal falling from the hopper is pushed forward during the inward stroke ram.
9. The low pressure air entering into the extension grate is supplied to ______________ in the multi retort stoker.
a) At incandescent zone
b) Thinner fuel bed
c) At inlet dampers
d) At extension grate
Answer: b
Explanation: The primary air is supplied from the main wind box to the fuel bed situated below the stoker. The partly burnt coal moves on to the extension grate. The low pressure air entering into the extension grate, wind from main wind box is supplied to the thinner fuel bed on the extension grate. The quantity supplied can be regulated by air damper.
10. What is the reason for using forced draft in multi retort stoker?
a) Maintaining combustion for longer periods
b) Helps in blowing away the ash and clinkers
c) Causes rapid combustion
d) Maintains the intensity of fire
Answer: c
Explanation: Forced draught causes rapid combustion. It is also necessary to introduce ‘over fire’ when high volatile coals are used to prevent the smoke formation. Combustion control is introduced into the stoker drive either by varying the ram stoke or by changing the rate of reciprocation.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Pulverised Fuel Burning”.
1. Proper regulation of Pulverized fuel results in _________
a) better fuel economy
b) high output work
c) efficient regulation of heat
d) proper combustion
Answer: a
Explanation: The rate of pulverized coal feed can be regulated properly resulting in fuel economy. Since coal is in the powdered form, coal of any grade can be used. Wide grade of low grade fuel can be burnt easily. Practically the coal used does not form any slagging or clinkers.
2. Why is combustion rate faster when the usage of pulverized coal is done in pulverized fuel handling?
a) Due to greater surface area
b) For using fuel in powdered form
c) Decrease in excess air
d) The speed at which the coal is fed
Answer: a
Explanation: The combustion rate is faster due to greater surface area of coal per unit mass of coal. It means more coal surface is exposed to heat and oxygen. This decreases excess air required for complete combustion and also decreases fan power. There is an increased rate of evaporation and higher boiler efficiency due to the complete combustion of fuel.
3. What is the advantage of breaking coal into smaller pieces in pulverized fuel handling?
a) Easy coal feeding
b) No clogging coal since they are in powder form
c) Exposes more surface of the coal
d) Increase in combustion rate
Answer: c
Explanation: By breaking, a given mass of coal into smaller pieces exposes more surface area for combustion. The increase of surface area exposed per unit volume with the decreasing diameter of coal particle. As shown in graph below, this increase varies rapidly after 0.01 inch diameter of the coal particle and there is no substantial increase after 0.001 inch diameter.
energy-engineering-questions-answers-pulverised-fuel-burning-q3
SURFACE AREA VS COAL PARTICLE DIAMETER
4. What is the main aim of Automatic control combustion in pulverized fuel firing?
a) To regulate the powder coal
b) To draw in air required for combustion
c) To maintain constant steam pressure
d) To draw out the ash formed
Answer: c
Explanation: Automatic control combustion applied to pulverized fuel fired boilers is effective in maintaining an almost constant steam pressure under wide load variations. It also gives fast response to load changes as rate of combustion can be controlled easily and immediately.
5. How is that using the pulverized system causes less trouble?
a) Rate of combustion is high
b) The operation is very quick and easy
c) No moving part in furnace
d) By using pulverized fuel system is totally free from slagging or clinker formation
Answer: c
Explanation: There are no moving parts in the furnace, subjected to high temperature therefore the life of the system is more and the operation is trouble free. The boilers can be started from cold very rapidly and effectively. The external heating surface is free from corrosion and fouling as smokeless combustion is possible.
6. Usage of highly preheated secondary air in pulverized fuel firing helps in ______
a) Heats fuel at pace
b) Takes less time to finish the process
c) Rapid flame propagation
d) Reduces the troubles and problems caused in the system
Answer: c
Explanation: Using highly preheated secondary air helps in raid flame propagation. This also increases the ability of system to use high combustion air temperature. The furnace makes it possible to complete combustion with minimum travel of flame travel since it is pre-heated.
7. In which type of machine is the coal reduced to fine powders?
a) Blender
b) Crushers
c) Grinder
d) Rollers
Answer: c
Explanation: Coal is reduced to fine powder in grinding mill. Coal is pulverized to increase its surface exposure. The pulverization of coal means of exposing a large surface area of the coal to action of oxygen and consequently accelerates combustion.
8. Where are pulverized fuel firers used?
a) Large capacity plants
b) Small capacity plants
c) Medium capacity Plants
d) Domestic plants
Answer: a
Explanation: Pulverized fuel firers are used in large capacity plants. The conventional or stoker firing methods were unable to meet the variable loads on the plants and were unsuitable for large capacity plants. Using pulverized fuel firer gives higher thermal efficiency, better control as per load on the plant and uses low grade coal.
9. With what is pulverized fuel mixed to burn like gas or oil?
a) Gasoline
b) Crude oil
c) Kerosene
d) Lubricant
Answer: b
Explanation: In the pulverized fuel firing system the coal is reduced to fine powder state by using a grinding mill and then projected in the combustion chamber with the help of hot air current. The coal in powder state may be mixed with crude oil and may burn like gas or oil.
10. Which air is supplied separately to ensure complete combustion in pulverized fuel firing system?
a) Primary air
b) Turbulence air
c) Secondary air
d) Blower air
Answer: c
Explanation: The amount of secondary air required to complete the combustion is blown separately and resulting turbulence in the high pressure combustion chamber helps in through mixing of fuel and air. For better combustion result this type of mixing is done.
11. What decides the efficiency of pulverized fuel firing system?
a) Turbulence of air
b) Size of coal powder
c) Primary air
d) Feeder
Answer: b
Explanation: The size coal powder decides the efficiency of the pulverized fuel firing system. The fineness of the coal should be such as 70%. Of it would pass through a 200 mesh sieve and 90% through 50 mesh sieve.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Pulverised Fuel Handling”.
1. Why do large power plants use pulverized fuel firing system?
a) Higher thermal efficiency
b) Uses high grade coal
c) Less smoke formation
d) Troubles created in this system are less
Answer: a
Explanation: Most of the large power plants use pulverized fuel firing system since it is higher in its thermal efficiency. And selection of it mainly depends upon the size of boiler unit, type of the coal available, nature of load on the plant, load factor, cost of the fuel and availability of skilled labors.
2. How is the fuel selected in the pulverized fuel system?
a) Depending on its size
b) Depending on its grade
c) Depending on volatile matter content
d) Depending the chemical composition
Answer: c
Explanation: In pulverized fuel firing system, coal with 20% volatile matter is considered as the best fuel for the plant, as high volatile coals are harder to grind when compared to low volatile coals. In stoker firing, the characteristics of the coal plays very important role in selection of coal.
3. What is the advantage of using pulverized fuel firing system?
a) Decreases maintenance of plant
b) Less wastage of the products
c) Less ash formation
d) No formation of clinkers
Answer: a
Explanation: The use of pulverized system increases the capital of and operating costs, but decreases maintenance of the plant and increases thermal efficiency. The pulverizer used to grind the coal should consume less power and should deliver the rated tonnage of coal.
4. What is unit pulverizer system also called?
a) Burner and pulverizer firing system
b) Central system firing system
c) Bin system firing system
d) Direct firing system
Answer: d
Explanation: The unit system is also called as the direct firing system. Most of the power plants with pulverized coal as the fuel are being installed with unit pulverizer. In this system each burner or a group of burner and pulverizer constitute a unit. The over head bunker supplies raw coal by gravity into a feeder where it is dried with the help of hot air.
5. On which factor is the coal fed to the pulverizing mill in pulverized fuel firing system?
a) Steam generating rate
b) Capacity of intake of coal
c) On the rate of speed of the feeder
d) Depending on the temperature that is governed inside the combustion chamber
Answer: a
Explanation: The feeder supplies coal too the pulverizing mill after drying coal in hot air. It is supplied at a variable rate governed by the combustion requirements of furnace and steam generating rate. In the pulverizing mill the coal is crushed to the required size .
6. Which type of draught system is used in the pulverized fuel firing system?
a) Forced draught
b) Balanced draught
c) Induced draught
d) Natural draught
Answer: c
Explanation: Induced draught system is used in pulverized fuel firing system. The primary air from the Induced draught fan carries pulverized coal from the mill to the burner through short delivery pipe. In the separator, the big coal particles are separated from the fine dust these again fall down into the mill.
7. Which system was used before direct firing system in pulverized fuel firing?
a) Unit system
b) Burner and pulverizer system
c) Bin system
d) Pulverizer
Answer: c
Explanation: Bin system was widely used before pulverizing equipment became reliable enough for continuous steady operation. This system employs a limited number of large capacity pulverizes at a central point to prepare coal for all the burners.
8. Why is direct firing system considered better than bin system in pulverizer fuel firing?
a) It has long operating procedure
b) The auxiliaries used in system consume large amount of power
c) The initial cost of system is very high
d) The transportation of coal is much more complex
Answer: a
Explanation: The bin system involves many stages of drying, storing and transportation and hence the process takes extra amount of time & chances of fire hazards are more. Never the less, it is still in use at many older plants.
9. Which separator is used to separate the pulverized coal in pulverized fuel firing?
a) Central inlet separator
b) Magnetic separator
c) Cyclone separator
d) Inertial separator
Answer: c
Explanation: Cyclones are mostly used for removing industrial dust from air or process gases. They are the principal type of gas-solid separator. The particulate is made to spin rapidly, heavier particle settle down and all the dust is removed out from the ducts. To also remove dust from the pulverized coal cyclone separator are used.
10. What is used to remove moisture air after cyclone separation in the pulverized fuel system?
a) Sponge pad
b) Dry filters
c) Fabric bag
d) Hot air
Answer: c
Explanation: A fabric bag filter is used to separate and exhaust the moisture air to the atmosphere and discharge the pulverized coal to storage bins, through the conveyor. This system uses all the equipment as used in unit system with higher capacity of each part. In addition to that the system also uses storage bins.
11. In what manner is the coal is fed to all the burners in pulverized fuel system?
a) Through a common feeder
b) Parallel feeding
c) From separate feeder
d) Series mesh feeding
Answer: c
Explanation: The pulverized coal is fed to the various burners through separate feeders. The bin may contain coal required for 12 to 24 hours of supply. The quantities of fuel and air can be regulated accurately and separately. This leads greater degree of flexibility.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Pulverised Mills – 1”.
1. How is coal pulverized in the ball mill?
a) By rotating the cylinder
b) By rolling the cylinder
c) By hammering the cylinder
d) By jolting the cylinder
Answer: a
Explanation: The pulverization in ball mill takes place as a result of action between the balls and coal, as the cylinder they are put in is made to rotate. The cylinder is partly filled with various sized steel balls. The cylinder is rotated at a velocity of 130 m/min periphery.
2. Why pre-heater air and the tempered air are introduced in the pulverizer of ball mill?
a) To carry the ash out
b) To increase the combustion rate
c) To carry pulverized coal
d) To dry the coal by removing the moisture
Answer: c
Explanation: A mixture of tempering air and hot air from pre-heater is introduced in the pulverizer. These streams of air carry the pulverized coal and pass through the classifier. The over-sized particles are thrown out of the air stream in the classifier and fine material is passed to the burner through exhaust fan.
3. The output of the mill can be controlled by the _________ located in the exhaust fan inlet duct.
a) Dampers
b) Blowers
c) Air duct
d) Ventilator’s
Answer: a
Explanation: The output of the mill can be controlled by the dampers located in the exhaust fan inlet duct. These dampers vary the flow of air through the mill, thus controlling the rate of fuel removed from the mill. The dampers are operated by the boilers automatic combustion control.
4. Feeder output in cylinder of a ball mill is regulated on the basis of?
a) Cylinder capacity
b) No of balls
c) Level of coal
d) Rotation speed of cylinder
Answer: c
Explanation: The feeder output is regulated by the coal level in the cylinder. When coal level in the cylinder attains sufficient height to seal off the lower channel than the differential control operates to stop the coal feed.
5. What is the pulverization capacity of the ball mill?
a) 10 tons of coal per hour
b) 20 tons of coal per hour
c) 50 tons of coal per hour
d) 80 tons of coal per hour
Answer: a
Explanation: A ball has the capacity of pulverizing 10 tons of coal per hour containing 4% of moisture requires 28 tons of steel balls and consumes 20 to 25 KW hr energy per ton of coal. A wide range of fuels including anthracite and bituminous coal which are difficult pulverize, can still be used.
6. Why ball and race mill is also called as contact mill?
a) Because of rolling action between the balls and races
b) Because of ramming action between balls and races
c) Because of swirling action of balls and races
d) Because of mixture of balls and races
Answer: a
Explanation: The pulverization or crushing action in ball and race mill takes between the two moving surfaces called balls and races. The rolling action happens between these two. Then the coal passes between the rotating elements time and again until it has been pulverized to the desired degree of fineness.
7. The pulverization is completed by a combination of crushing impact and _______ between grinding surfaces.
a) Accretion
b) Erosion
c) Attrition
d) Dissolution
Answer: c
Explanation: The pulverization is completed by a combination of crushing impact and attrition between grinding surfaces. The coal is crushed between two moving surfaces: balls and races. The upper stationary race and lower rotating race is driven by a worm and gear, hold the balls between them.
8. What type of feeder is used to supply the coal in ball and race mill?
a) Ring main feeder
b) Parallel feeder
c) Radial feeder
d) Rotating table feeder
Answer: d
Explanation: The coal is supplied through the rotating table feeder at the upper right to fall on the inner side of the races. The moving balls and races trap coal between them to crush it to powder. Spring holds down the upper stationary race and adjusts the force needed for crushing.
9. Which type of fan is used in the ball and race mill?
a) Forced draught fan
b) Balanced draught fan
c) Artificial draught fan
d) Natural draught fan
Answer: a
Explanation: A forced draught fan is used to supply hot air to the mill through the annular space surrounding the races. The air picks up the coal dust as it flows between the balls and races and then enters into the classifier above it.
10. What is the purpose of fixed vanes in the ball and race mill?
a) Forms a cyclonic flow
b) For easy movement of the coal
c) For directing the airflow
d) For barring the exhaust air to enter back into mill
Answer: a
Explanation: The fixed vanes make the entering air to form a cyclonic flow throwing the oversized particles to the walls of classifier. The oversized particles slide down for further grinding in the mill. The coal particles of required size are taken to the burners with air from the top of the cylinder.
11. Why are heavy impurities provided in the process of ball and race mill?
a) To resist upward thrust caused by secondary air stream
b) To resist downward thrust caused by primary air stream
c) To resist upward thrust caused by primary air stream
d) To resist downward thrust caused by secondary air stream
Answer: c
Explanation: The mill is provided with a means of separating heavy impurities from the coal and thus reducing wear and possible damage to the grinding element. These heavy particles resist the upward thrust caused by the primary air stream and collect in a compartment in the base of mill, and then they are removed periodically.
12. What is done when there is requirement for more coal in the ball and race mill?
a) The primary air flow is increased
b) The combustion intensity is reduced
c) The secondary air flow sucks out the light coal particles
d) The hopper is fully opened
Answer: a
Explanation: When there is requirement for more coal, the primary air flow is increased automatically and its higher velocity in the mill carries additional coal in the furnace. This action reduces the amount of coal in the pulverizer and decreases the pressure drop, causing the feeder controller to supply more coal.
13. What happens due to the pressure in the pulverizer?
a) Pulverized fuel is blown into boiler room
b) Increases the rate of combustion
c) Makes the process is vigorous
d) The large particles in the pulverized fuels are removed out
Answer: a
Explanation: As the casing of the pulverizer is under pressure, the leakage of fine coal through the mill casing causes the pulverized fuel to be blown out into the boiler room. The fan used with this mill handles only air therefore the blades erosion by coal particle is eliminated.
14. What is the main disadvantage of race and ball mill pulverizer?
a) Mill requires extra floor area
b) It is directly connected to the motor
c) High power consumption
d) Greater wear
Answer: d
Explanation: Ball and race mill have greater wear compared to other pulverizers. The advantages of lower space occupied, lower power consumption in kW hr/ton of coal pulverized, lower weight and lower capital cost have outweighed the wear problem and these pulverizers found general acceptance.
This set of Energy Engineering Interview Questions and Answers for Experienced people focuses on “Pulverised Mills – 2”.
1. In which mill is the pulverization of coal is made by the impact?
a) Hammer mill
b) Bowl mill
c) Ball mill
d) Ball and race mill
Answer: a
Explanation: In the hammer mill the pulverization of coal is made by impact and this is also called as impact mill. The coal in pulverizer remains in suspension during the entire pulverizing process. All the grinding elements and the primary air fan are mounted on a single shaft.
2. What is done in the primary stage of the grinding in impact mill?
a) Coal is reduced to fine granular state
b) Coal is broken down in medium pieces
c) Coal is dried up to remove the moisture content
d) Coal is mixed up with the other state of fuel to improve the combustion efficiency
Answer: a
Explanation: The primary air fan induces flow of air through the pulverizer carrying the coal to the primary stage of grinding. In the primary stage of grinding, the coal is reduced to fine granular state by impact with a series of hammers and then into the final stage where pulverization is completed by attrition.
3. What is the purpose of rotary scoop shaped rejecter arms in impact mill?
a) To send back the coal back into grinder for second run
b) To throw the large particles back into the grinder
c) To eliminate ash from the pulverizer
d) To eliminate rocks and solid particles that has mixed up with the coal
Answer: b
Explanation: The finely pulverized coal in the final stage of grinding is carried with the air to the burner through the rotating scoop rejecter arms which throw the large particles back into the grinding section. The final stage grinding consists of pegs carried on a rotating disk and travelling between stationary pegs.
4. How is pulverization done in bowl mill?
a) By bowl and steel balls
b) By bowl and roller
c) By bowl and impact hammer
d) By bowl and batan
Answer: b
Explanation: The bowl mill consists of rollers and power driven bowl in which pulverization takes place as the coal passes in between the sides of the bowl and the rollers. The automatic control charges the supply of coal to the bowl.
5. What does the primary air that is induced by draught does in a bowl mill?
a) Blows away ash
b) Control the flow of coal
c) Provides air for the combustion
d) Draws heated air
Answer: d
Explanation: The primary air by induced draught fan draws a stream of heated air through the mill, carrying the pulverized coal into a stationary classifier located at the top of pulveriser. The classifier returns the coarse particles of coal to the desired fineness is carried to the burner through the fan.
6. Which force is used to throw away the heavy particles in the bowl mill?
a) Gravity force
b) Centrifugal force
c) Centripetal force
d) Spring force
Answer: b
Explanation: The coal pulverized is carried to the burner through the fan. The impurities in the coal containing heavy particles are thrown over side by centrifugal force as these enter the rotating bowl/ the heavy particles thrown out fall into the space below the bowl.
7. On what basis is selection of bowl mill is not done?
a) Total moisture content of coal
b) Volatile matter
c) Ash producing capacity
d) Grindability
Answer: c
Explanation: The selection of bowl mill is done on the basis of total moisture content of coal, sulfur and mineral content , Grindability, volatile matter .
8. What is not the cause of mill fire?
a) Hot startup with normal load
b) Pyrite building from pyrite plows failure
c) Accumulation of coal dust in mill devices
d) Localized hot spots from poor primary air flow
Answer: a
Explanation: Mill fires are more often caused due to pyrite building, hot startup on heavy load, accumulation of coal dust etc. the cause of fire is also dependent upon coal properties that exceed pulverizing rating.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Fuel Burning Equipments”.
1. What is the function of coal burners?
a) To burn pulverized coal by using secondary air
b) To burn pulverized coal in presence of Primary and secondary air
c) To burn pulverized coal by using induced draught
d) To burn the pulverized coal in short amount of time
Answer: b
Explanation: Function of the coal burner is to burn pulverized coal in the presence of primary and secondary air in a boiler furnace. Coal burners are classified according to their design and arrangement in the furnace.
2. Which coal burner is called Long-flame burner?
a) Tangential burner
b) Turbulent burner
c) Stream line burner
d) Cyclone burner
Answer: c
Explanation: Stream line burner is called as Long-flame burner, also known as U-flame burner. It is designed to fire downwards in the furnace without any turbulence. Thin flat streams of air and fuel mixture is discharged in the furnace which travels considerably long distance producing long flame.
3. The secondary air in the stream-liner coal burner is fed flames from which direction?
a) At straight angle
b) Opposite to the fuel flow
c) At Right angle
d) Along the fuel
Answer: c
Explanation: Heated secondary air in the stream-liner coal burners fed at right angles to the flame. It ensures proper mixing of air and fuel. This type of burner is suitable for burning fuels with low volatile matter as fuel flows at low velocity.
4. Which coal burner has the circular discharge orifices?
a) Tangential burner
b) Stream-line burner
c) Turbulent burner
d) Cyclone burner
Answer: c
Explanation: Turbulent is made up of circular discharge orifices or with straight narrow outlets. It is placed in the wall of water cooled furnaces. The fuel and air mixture pass through the burner such that they mix properly at furnace entrance.
5. In which coal burners are fuel and air streams ejected in horizontal direction?
a) Tangential burner
b) Cyclone burner
c) Stream-line burner
d) Turbulent burner
Answer: a
Explanation: In tangential burners, fuel and air streams are ejected in horizontal direction tangent to an imaginary circle at the centre of the furnace. The burners are placed at the corners of the furnace to ensure intense turbulence and thorough mixing of fuel and air.
6. Which coal burner is used to burn crushed coal instead of pulverized coal?
a) Cyclone burner
b) Tangential burner
c) Turbulent burner
d) Stream-line burner
Answer: a
Explanation: Cyclone burners are used to burn crushed coal instead of pulverized coal. This is to eliminate fly ash handling problems. It consists of a cyclone furnace. Crushed coal of about 8 mm size is fed from the feeder to the centre of the cyclone along with primary air.
7. In which form does the coal burned rapidly in cyclone burner drains down the inner wall of furnace?
a) Powdered
b) In form of small chips
c) Metal slag
d) Gaseous form
Answer: c
Explanation: The ash formed due to rapid burning of coal drains down the inner wall of the furnace as molten slag. Hot flue gases along with 10 to 20% of fly ash enter the furnace. Due to centrifugal action most of the fly ash is thrown against the furnace wall and is drained out along with molten slag.
8. Which type of oil burners are used for domestic purposes?
a) Atomizing burner
b) Vaporizing burner
c) Steam jet atomization burner
d) Mechanical atomization burner
Answer: b
Explanation: The vaporizing burners are used for domestic purpose especially in portable air heaters, cooking stoves etc. petromax stove which burns kerosene is a classical example of a vaporizing burner. Here an upward moving high velocity fuel jet is allowed to strike against hot moving plate. The vapor burns with a short intense flame.
9. Which type of oil burners are commonly used in oil-fired furnaces of steam generators?
a) Vaporizing burner
b) Mechanical burner
c) Atomizing burner
d) Air jet burner
Answer: c
Explanation: Atomizing burners are very commonly used in oil-fired furnaces of steam generators. The oil is divided into fine particles to increase the surface area of contact with the combustion air. Due to atomization a homogeneous mixture of oil and air is produced which is fired in the furnace.
10. How is oil pressurized in mechanical atomization of atomizing burner of oil burners?
a) By positive displacement pumps
b) By centrifugal pumps
c) Helicon-axial pumps
d) Electric submersible
Answer: a
Explanation: In mechanical atomization of atomizing burner of oil burners, the oil is pressurized by using a positive displacement pump. It is used in high capacity steam generating furnaces. In order to improve efficiency and flow conditions the viscosity of the oil is reduced by heating it to about 120 o C.
11. How does atomization of fuel occur in an atomizing burner of oil burner?
a) High pressure movement of fuels
b) By spraying the fuel at high pressure
c) By impinging two streams of fuel
d) By spark ignition method
Answer: c
Explanation: In the atomizing burner, oil is delivered under pressure through a central tube. Steam or air is supplied along the annular space between the oil pipe and the concentric outer tube. Near the tip of the burners the two streams impinge resulting in atomization of fuel.
12. Which type of gas burner is used to control flame length?
a) Ring burner
b) Sealed burner
c) Electric burner
d) Standing pilot burner
Answer: a
Explanation: Ring burners are used to control the flame length. The rate of gas flow can be controlled by using dampers. The gas flows through an annular ring, whereas air is induced both around and within the annular ring.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Fuel Handling System, Storage of Coal”.
1. How is the fuel handled generally outside the plant?
a) Mechanically
b) Manually
c) Robotic technology
d) Physically
Answer: a
Explanation: It is absolutely essential to have an efficient fuel handling system in power plants. Since majority of the plants operate using coal as a fuel, it is necessary to study about coal handling system. Coal can be handled either manually or mechanically. But, citing the capacity of modern power plants it is almost impossible to handle coal manually. That means mechanical handling of coal is inevitable.
2. Why is fuel need to be stocked in steam power plant?
a) To supply to nearby other steam plants
b) For overusing when plant is run for extra periods
c) For emergency possible cases
d) For Non-stop work of power plant
Answer: c
Explanation: With more and more number of commissioning of large capacity steam power plants, it is very essential to have an effective means of transporting coal from coal mines to the plant site and subsequently store it to meet the emergencies.
3. What is the ideal site for power plant?
a) In hilly regions
b) On islands
c) Near water resources
d) In center lands
Answer: c
Explanation: An ideal site for power plant is near water source. If the plant is situated near the sea or river, coal can be economically transported in bulk quantity by ships or boats or barges. After unloading the coal by mechanical means, coal is either stored in the plants site or conveyed to the plant.
4. Which type of transportation system is ideal for transporting coal directly to the point of consumption?
a) Road transportation
b) Sea or river transportation
c) Transportation by rail
d) Transportation by air
Answer: a
Explanation: Road transportation is ideal for transporting coal directly to the point of consumption. Such a means is suitable for supplying coal to a small capacity plant. Trucks or tippers are used to supply coal for this purpose.
5. What is in plant coal handling system?
a) Maintenance of coal during emergencies
b) Maintenance of coal inside the boiler
c) Maintenance of coal inside the power production area
d) Maintenance of coal while transporting/moving it
Answer: c
Explanation: For easy, smooth and rapid operation mechanical handling system is embraced for inplant handling of coal. Inplant handling begins right from the coal delivery point unto the furnace firing system.
6. What is the main characteristic of in plant coal handling system?
a) It should be easy to handle
b) Should be simple in construction
c) Free from repetitive handling
d) Free from corrosion problems
Answer: c
Explanation: It should have minimum handling operations and should be free from repetitive handling. For easy inspection and maintenance it should have centralized handling units. Its capacity should be well above the requirement of coal during peak hours.
7. Why is it necessary to have a coal storage yard near the plant?
a) To supply to other nearby power plants
b) To cut down on varying transportation rates
c) To face any emergencies
d) Due to higher rate of deterioration due to reduction
Answer: c
Explanation: To meet the continuous demand of coal and to face any emergencies due to the short supply of coal, it is always desirable to have a coal storage yard near the plant. Capacity of such yard would be about 10% of annual consumption to a maximum of 25% of annual consumption.
8. Where should coal be dumped?
a) On solid ground
b) In the water
c) By mixing with other form of fuels
d) Near the plant
Answer: a
Explanation: Coal should be dumped on a solid ground completely free from standing water. It should be protected from direct sunlight preferably and should be done so in order to reduce chances of oxidation and combustion.
9. What is the advantage of stocking the coal in huge heaps?
a) Prevents from coal being oxidized
b) Provides grip for the storage
c) Prevents air circulation in the interior of heap
d) The moisture content will be eliminated
Answer: c
Explanation: Coal is piled in heaps of 10 to 12m height on a concrete floor, by compacting it in the layers of 20 to 30cm thickness using bulldozers. This prevents air circulation in the interior of the heap. The heap top is given a gentle slope to drain off rain water immediately without washing the coal.
10. How the oxidation of coal is eliminated?
a) By exposing it to the sunlight
b) By turning the entire coal heap upside down periodically
c) By circulating air uniformly
d) By burning coal at very high temperatures
Answer: c
Explanation: The heat of oxidation is removed by circulating air uniformly through layers. Air thus circulated carries away the excess heat, maintaining coal below its combustion temperature of 343K. Oxidation can also be avoided by sealing the coal heap asphalt, fine coal dust or bituminous powder.
11. Why is it necessary to use noncandescent materials in place of coal storage area?
a) To avoid it from catching fire
b) To act as a fire resistor during the cause of fire
c) To avoid it from acting as a supporter of fire
d) To provide a cool environment
Answer: a
Explanation: Coal is susceptible to spontaneous combustion due to heating during natural oxidation of new coal surfaces. Second, coal dust is highly combustible and explosion hazard. If a coal dust cloud is generated inside an enclosed space, and an ignition source is present, an explosion can ensure.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Stages of Coal Handling”.
1. In which mode of transport are rotary car dumpers used?
a) Road transport
b) Rail transport
c) Transport by sea or river
d) Inside the plant handling
Answer: b
Explanation: Depending on the mode of transport viz. by sea or road or rail, coal unloading done. Rotary car dumpers are used when the transport is done by rail also coal towers and coal accelerators are used. Coal towers, unloading bridges and self unloading boats are used if the outplant handling of the coal is by sea or river.
2. What is the function of sizer in coal handling?
a) To separate the coal depending on size
b) To check the amount of fuel that is supplied
c) To pick the coal of required size
d) To divert the coal flow into different burners
Answer: c
Explanation: The function of the sizer is to pick the coal of requires size, which is coming from the crusher. The un-sized coal is fed back to the crusher. The function of crusher is to crush the coal to uniform size.
3. What is the function of magnetic separator in coal handling?
a) To remove impurities
b) To separate bituminous coal
c) To remove iron particles
d) To separate metal contents
Answer: c
Explanation: The function of the magnetic separator is to remove iron particles which otherwise may choke the burners besides damaging other equipment’s. The iron particles are trapped by the magnetic pulley while the belt carrying coal passes over it. It is collected in a chute.
4. What is the purpose of bucket elevators in coal handling?
a) Used to move coal horizontally
b) Used to lift coal vertically
c) Used to separate the crushed coal and pulverized coal
d) Used to pour the coal vertically at right angles into furnace
Answer: b
Explanation: Centrifugal and continuous types of bucket elevators are used for lifting coal to moderate height . It consists of buckets fixed to a chain moving over two sprockets. The buckets carry coal from bottom and discharge at the top at a speed ranging between 15 m/min to 36 m/min.
5. What is the function of Gab bucket conveyor in coal handling?
a) To lift the coal vertically
b) To crush the coal
c) To move coal from one place to another
d) To separate crushed coal and powdered coal
Answer: c
Explanation: Grab bucket conveyor can grab as well as convey coal from one place to another. It is used with a crane or tower and it has different capacities. It is very essential when all other means of transporting coal is not viable. It has high initial cost but low operating cost.
6. Out of all conveyors which type of conveyor has a greater capacity to convey large amount of coal?
a) Belt conveyor
b) Chain conveyor
c) Screw conveyor
d) Scraper conveyor
Answer: a
Explanation: Belt conveyor is used for transporting large quantities of coal over long distances. It consists of an endless belt made of rubber, balata or canvass running over pulleys or end drums. It is economical means of coal transportation at rapid rate.
7. What is the distance at which belt conveyors can convey?
a) 100m
b) 200m
c) 50m
d) 500m
Answer: d
Explanation: Belt conveyors can handle upto 50 to 100t/h of load can be carried over a distance of about 500m. These conveyors can be used with inclination upto 20° to the horizontal moving at an average speed of 60 to 90 m/min. However it cannot be used for carrying coal at greater heights.
8. To what is helicoids screw in screw conveyor is attached?
a) To the shaft
b) To the inner case
c) To the bearings
d) To the outer casing
Answer: a
Explanation: Screw conveyor is used to transmit coal. It consists of an endless helicoids screw of diameter 150 mm to 500 mm wound around a rotating shaft. One end of the shaft is connected to the drive whereas the other end is supported by a bearing.
9. In what speed range does screw conveyor run at?
a) 60 – 80 rpm
b) 20 – 100 rpm
c) 60 – 120 rpm
d) 90 to 180 rpm
Answer: c
Explanation: The screw along with the shaft in screw conveyor rotates at about 60 rpm to 120 rpm and carries coal from one end to another. Screw conveyors are designed to suit different load capacities. These can only be used in very short ranges and tend to get hot if used for longer amount of time.
10. Which type of conveyor has shorter life span?
a) Flight conveyor
b) Belt conveyor
c) Screw conveyor
d) Grab bucket conveyor
Answer: a
Explanation: Flight conveyor is used for filling large number of storage bins situated under the conveyor. It consists of a steel scrapers attached to chain mechanism. Steel scrapers scrap the coal through a trough and discharge it at the bottom.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Coal Weighing Methods”.
1. What does ESP stand for in dust collection?
a) Endothermic sensor plate
b) Extrasensory perception
c) Electrostatic precipitators
d) Electronic stability program
Answer: c
Explanation: With stringent air quality restriction by the governments, majority of power plants in the world use electrostatic precipitators for dust removal. An ESP can handle large volumes of flue gases accompanied low pressure drop and high collection efficiency . It facilitates easy removal of dust particles.
2. What happens when high voltage is applied to the electrodes in electric dust collectors?
a) Forms uniform electric field
b) Corona is formed
c) The whole system gets charged
d) Ions move from emitting electrode to collecting electrode
Answer: b
Explanation: When the high voltage is applied, it generates a unidirectional non uniform electric field having greater magnitude at the discharge electrodes. This result in a blue luminous glow called corona around them. This corona is an indication of negatively charged ionized gas molecules which travel from discharge electrodes to grounded collection electrodes.
3. Why is weighment of the coal essential in the plants?
a) For knowing the quantity of the coal present
b) For getting optimum efficiency
c) For knowing which type of coal has good fuel content
d) To separate the grades of coal
Answer: b
Explanation: The consumption of coal and its cost has major important once as coal forms the basic ingredient of the thermal power plant. Weighment of coal is essential for getting optimum plant efficiency at reduced cost using weighers.
4. Which type of weigher is commonly used all over the world?
a) Electronic weighers
b) Mechanical weighers
c) Pneumatic weighers
d) Nuclear weighers
Answer: b
Explanation: Mechanical weigher is commonly used all over world. This based on mechanical principle. This works on a lever system mounted on knife edges and bearings that connected to a resistant like a spring or pendulum. The resultant value obtained by multiplication of load and speed values is displayed by a digital counter.
5. Which type of weighers is used in place where the electronic weighers are not allowed?
a) Pneumatic weighers
b) Mechanical weighers
c) Nuclear weighers
d) Electronic weighers
Answer: a
Explanation: The pneumatic weighers use a pneumatic transmitter weigh head and the corresponding air pressure determined by the load applied and is transmitted to the weight indicating receiver may be used where electronic system is not permitted for use.
6. Electronic weighers are based on which principle?
a) Semiconductor principle
b) Electromagnetic principle
c) Load cell principle
d) Junctions
Answer: c
Explanation: The operation is based on load cell principle. The load cells produce voltage signals proportional to the applied load. This system maintains high accuracy in measurement. Its performance is affected by temperature, noise, dust and humidity of the air.
7. What types of rays does the nuclear weigher used to measure the weight?
a) Infrared rays
b) Ultraviolet rays
c) Gamma rays
d) X-ray waves
Answer: c
Explanation: Nuclear weighing system operates on gamma ray, Works on gamma rays absorption principle. A radio-active source located in the source head emits gamma rays which pass through the material on the conveyor to the detector.
8. What is the main disadvantage of the nuclear weigher?
a) They are not mobile
b) Accuracy depends on speed of material
c) They are big in size, requires large amount of space
d) Consumes large amount of electricity
Answer: c
Explanation: Main disadvantage of the nuclear weighing machine is that its accuracy depends on a consistent speed of material movement and the condition of the detectors since this should be kept clean at all times as otherwise absorption value of gamma-rays will be affected.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Mechanical Dust Collectors”.
1. Gravitational separator works on the principle of __________
a) Size of particulate
b) Shape of particulate
c) Weight of particulate
d) Color of the particulate
Answer: c
Explanation: Gravitational separation is an industrial method of separating two components, either a suspension, or dry granular mixture where separating the components with gravity is sufficiently practical, i.e. the components of the mixture have different specific weights.
2. What is the use of baffles in the gravitational separators?
a) To separate types of dust
b) To settle the dust by letting them to strike
c) To control the flow of dust particles
d) To blow the dust
Answer: b
Explanation: Baffles are placed in the direction of flow of flue gases. The dust particle strike down and settle. Heavier dust particles settle at the bottom by striking on to the baffles and lighter dust particles are exhaust into atmosphere.
3. What is the most effective advantage of gravitational separators?
a) They consume no power
b) They just need small amount of space for operation
c) They are cost effective
d) Time taken for operation is very less
Answer: c
Explanation: The most notable advantage of the gravitational separators is their cost effectiveness. Gravity separation is an attractive unit operation as it generally has low capital and operating costs, uses few if any chemicals that might cause environmental concerns.
4. Which principle does cyclone separator use?
a) Gravitational force
b) Vortex velocity
c) Inertia
d) Temperatures of air
Answer: c
Explanation: Cyclone separators or simply cyclones work on the principle of inertia to move particulate matter from flue gases. In these high velocity dusts carrying gas is made to pass through conical separator in tangential direction. This results in centrifugal action, throwing away the heavier dust particles to the sides of conical chamber.
5. Cyclone separators are also known as __________
a) Twist cleaners
b) Squall
c) Pre-cleaners
d) Zephyr cleaners
Answer: c
Explanation: Cyclone separators are a part of a group of air pollution control devices known as pre-cleaners as they generally used to roughly remove large pieces of particulate matter. This prevents finer filtration methods from having to deal with large, more abrasive particles later on.
6. What is called when several cyclone separators are operated parallely?
a) Octa-cyclone
b) Multi-cyclone
c) Center-cyclone
d) Para-cyclone
Answer: b
Explanation: When several cyclone operators are operated parallely, when this system is setup it is called multi-cyclone. It is important to note that cyclones can vary drastically in their size. The size of the cyclone depends largely on how much flue gas must be filtered, and thus larger operations tend to need larger cyclones.
7. What is the range of particulate removing efficiency of cyclone separators?
a) 50-99%
b) 20-80%
c) 70-90%
d) 70-95%
Answer: a
Explanation: Cyclone separators are generally able to remove somewhere in the range of 50-99% of all particulate matter. How well the cyclone separators are actually able to remove this matter depends largely on particle size. If there is large amount of lighter particulate matter, less of these particles are able to be separated out. Because of this, cyclone separators work best on flue gases that contain large amounts of big particulate matter.
8. What is Baghouse?
a) Filters arranged in parallel form
b) Filters arranged throughout the system
c) Filters arranged randomly
d) Filters arranged alternatively
Answer: a
Explanation: A fabric filter element made up of a long hollow cylindrical tube, that provides a large surface per unit of gas volumetric flow rate is called as baghouse filter and a system consisting of large number of such filter elements arranged in parallel rows is called a baghouse.
9. What is the work of the baghouse filter?
a) To remove the hot air from furnace
b) To separate the solid particles from dust produced
c) To remove dust particles from flue gas
d) To wash away the contamination of dust on the walls of furnace
Answer: c
Explanation: Baghouse filters are used to remove dust particles from the flue gas produced from the combustion in boiler. These are also called as fabric filters or fabric dust collectors, designed to use fabric filter tubes, envelopes or cartridges to capture or separate dust and particulate matter when the gas is made to pass through the voids.
10. What is the use of wet scrubber in the dust collection?
a) Remove flue gas
b) Remove Scales on the furnace surface
c) Remove the dust that has the moisture content
d) Remove pollutants
Answer: d
Explanation: Wet scrubber is used remove the pollutants. The polluted gas stream is brought into contact with the scrubbing liquid, by spraying it with the liquid, by a pool of liquid, or by some other contact method, so as to remove the pollutants.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Soot Blowers”.
1. The method of removing soot from the power plant machineries is known as _________
a) Soot cleansing
b) Centrifugation
c) Soot blowing
d) Bioleaching
Answer: d
Explanation: The products of combustion cling to the water tubes, economizer tubes, air preheater tubes and super heater tubes. This lowers the efficiency of the plant by reducing heat transfer. So, regular removal of soot or dust is necessary this method is known as soot blowing.
2. Why nozzle tubes are provided in the soot blowers?
a) To moistures the dust
b) To admit high pressure steam
c) To blow away the soot
d) To suck in the dust and exhaust it at high pressure
Answer: b
Explanation: The usual form for the smaller boilers is a dead-end tube projecting through the setting and extending into the tube banks. A number of small lateral nozzles are provided and the external head is arranged so that high pressure steam can be admitted to the tube and at the same time the tube is rotated around its axis.
3. Which type of blower advances into the furnace, cleans and comes back?
a) Wall blower
b) Retractable blower
c) Air heat blower
d) Insert able kinetic blower
Answer: b
Explanation: Soot blower consists of a set of tubes fitted with nozzles carrying high velocity jet of steam or air. In the hotter parts of the boiler, the blower advances into the furnace, cleans the heat transfer surfaces and comes back. This type of soot blower is known as retractable soot blower.
4. Why are there number soot blower units in large blower?
a) To obtain high efficiency
b) To clean the boiler in short amount of time
c) To clean adequately
d) For easy replacement
Answer: c
Explanation: Steam jets clean soot from heating surface in their proximity, but the action is limited in extent in a close array such as tube banks; hence several units may be needed to clean the boiler adequately. It is quite common to see 8 to 16 units in a large boiler.
5. Why operating heads of soot blowers are automated?
a) Because they are tedious to operate manually
b) Because they cannot be handled at once
c) Because they are positioned at different parts of machine
d) Because it is quicker by automation
Answer: a
Explanation: Soot blowers are tedious to operate manually, and since must not all be operated simultaneously, the operating heads are electric motor powered and operated by remote control on an automatic sequential basis.
6. Why on some boilers the draft system controls have to be positioned abnormally in soot blowers?
a) To avoid the soot being blown back into boiler
b) To get a good grip for blowing out the soot from the boiler
c) due to lack of space in the boiler
d) To avoid the heat of boiler affecting the soot blowers
Answer: a
Explanation: On some boilers the automatic draft system controls have to be positioned for abnormally high draft before beginning the soot blowing operation; otherwise the release of stem into the setting may blow soot and smoke into the boiler room.
7. In which state would be the soot blower when it’s not in use?
a) Dry and cooled
b) Dry and uncooled
c) Wet and cooled
d) Dry and hot
Answer: b
Explanation: When not in use the soot blower tube of the system would be dry and uncooled, and subject to gas temperatures. Even with alloy tubes the deterioration is relatively rapid on units normally experiencing high gas temperatures.
8. What is the advantage of using retractable soot blower?
a) Has high blowing capacity compared to steam and wall blowers
b) Protects from high temperatures when not in use
c) Consumes less amount of electricity
d) Produces less amount of noise
Answer: b
Explanation: Retractable blower, though more expensive initially, have the advantage of protection from high temperature when not in use. Also, using only two travelling nozzles, the jet can be larger without excessive steam drain, and the projected blast distance is greater.
9. Why is it necessary to observe temperature drops in the soot blower?
a) To avoid net loss
b) To avoid the soot getting struck in soot blower
c) To avoid over usage
d) To avoid overconsumption of electricity
Answer: a
Explanation: It is necessary to observe temperature drops routinely. Obviously if the temperature drops 24°C after blowing, the interval might well be decreased, where as if 12°C were observed; it could represent a net loss because the value of the steam used was more than that of the increment of flue gas heat.
10. Is there a chance of fire due to the accumulation soot inside the boiler.
a) True
b) False
Answer: a
Explanation: A soot fire can be damaging to a boiler because it can cause localized hotspots to occur in the tubes. These hotspots may reach temperatures that weaken the materials of the tubes. Soot blowers reduce the risk of soot fires and their resulting damage.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Function of Boilers”.
1. What is the function of boiler?
a) To burn the fuel in a confined closed system with the supply of air
b) To generate steam at varying pressure
c) To generate steam at constant pressure
d) To produce flue gases by burning fuel at a given pressure
Answer: c
Explanation: Function of boiler is to generate steam at constant pressure as per the process requirement. The steam generated may be nearly dry saturated or superheated steam. Constant pressure in the boiler is maintained by generating the steam equal to the steam flowing out of the boiler.
2. Why single boiler unit per turbine is equipped commonly?
a) For better turbine control
b) To deduce the costs
c) For overcoming losses of power
d) To improve the efficiency
Answer: a
Explanation: In modern power plants it is very common to use a single boiler unit per turbine. This leads to simpler piping systems and relatively easier boiler and better boiler control. And also operating is easier when the connection is made in this type.
3. What is the critical average pressure at which the single boiler unit per turbines is designed to handle?
a) 150 bar
b) 220 bar
c) 740 bar
d) 575 bar
Answer: b
Explanation: Single boiler per unit turbines is designed to operate at average critical temperature of 220bar. If the boilers are designed to operate above or below the critical pressure, than they are known as super critical boilers are once through boilers. If the boilers are designed to operate below the critical pressure than they are known as sub critical or drum boilers.
4. How can be the plant efficiency of steam power plant is increased?
a) By using high pressure and high temperature steam
b) By equipping ash and flue gas clearance system
c) By maintaining the boiler on daily basis by cleaning the soot and combustion products
d) By using better and efficient type of fuel for combustion
Answer: a
Explanation: The plant efficiency can be increased by using high pressure and high temperature steam. This also reduces the cost of electricity production. The development of newer materials permitted the use of higher operating pressure and temperature of the boiler.
5. Which type of boilers is preferred cost wise when the boilers are required to raise less than 30 tonnes of steam?
a) Flued boiler
b) Cornish boiler
c) Butterley boiler
d) Shell boiler
Answer: d
Explanation: The use of shell boilers are considered to be cheaper when the boilers are required to raise less than 30 tonnes of steam per hour and at pressures 30bar. Above these limits, i.e. for high pressure and high output, water tube boilers are preferred.
6. What is the temperature at which the steam boilers are capable to withstand?
a) 200 o C
b) 280 o C
c) 540 o C
d) 358 o C
Answer: c
Explanation: The modern high pressure boilers have steam capacities of 30 to 650 tonnes/hour and with pressure of upto 160 bar & maximum steam temperature of about 540 o C. Also the furnace shape is not limited to cylindrical form; hence furnace shape can be changed to suit wide range of situations.
7. The _________ may have water circulation either by natural means due to difference in density or by external means.
a) Piping
b) Tubes
c) Furnace
d) Boiler
Answer: d
Explanation: The boiler may have a water circulation either by natural means due to difference in density or by external means . All modern high pressure boiler plants use a pump to force the water to circulate through the boiler plant. The use of natural circulation is limited to the subcritical boilers.
8. What increases as steam pressure increases inside a boiler?
a) Force
b) Density
c) Rate of steam conversion
d) Viscosity
Answer: b
Explanation: As the steam pressure increases, its density also increases while the corresponding increase in temperature causes density of water to decrease. This makes the pressure difference causing water flow to decrease.
9. What is needed to be increased to increase the heat transfer rate in the boiler?
a) Gas velocities
b) Fuel input
c) Water velocities
d) Air supply
Answer: c
Explanation: Water velocity is required to be increased rather than gas velocities to increase the rate of heat transfer rate in the boiler, because a considerable increase in pressure is more easily produced with water than with gas. Hence, for a given output in boiler, smaller diameter tube may be used.
10. In what is water in high pressure boiler circulated through?
a) Conduits
b) Cove
c) Channel
d) Tubes
Answer: d
Explanation: In high pressure boilers, water is circulated through the tubes. If the flow of water takes place through one continuous tube, there is a large resistance due to friction and also pressure drop will be more. If the flow is arranged through a parallel system of tubing i.e., through several sets of tubes which are arranged parallel pressure loss will be reduced. This also provides better control over the steam quality.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Boiler Classification”.
1. On what basis are fire and water tube boilers are classified?
a) Depending the combustion products formed
b) Depending the state of fuel
c) Depending on the steam formation rate
d) Depending tubular heating surface
Answer: d
Explanation: Based on the contents of the tubular heating surface, boilers are primarily classified as fire tube boiler and water tube boiler. Fire tube boilers those in which production of combustion pass through the tubes and water tube boilers are those in which the products of combustion surround the water tubes from outside.
2. Cornish boiler is an example of which type of boiler?
a) Fire tube boiler
b) Water tube boiler
c) Vertical tube boiler
d) Externally fired boiler
Answer: a
Explanation: Cornish boiler is an example of fire tube boiler and also includes Cochran, Lancashire, and Locomotive and scotch marine boilers. Fire tube boilers are those in which the products of combustion pass through the tubes and water lies around the outside of tubes. These boilers operate at moderate pressure and more suitable to generate 3-8 tons of steam per hour which is used in process heating.
3. Stirling boiler is an example of which type of boiler?
a) Inclined tube boilers
b) Mobile boiler
c) Fire tube boiler
d) Water tube boiler
Answer: d
Explanation: Water tube boilers are those in which the products of combustion surround the water tubes from outside. Cold water enters the tubes and leaves hot. These boilers operate at very high pressures and are used for power generation.
Ex: Babcock-Wilcox boiler, Stirling boiler.
4. Which of these is a stationary boiler?
a) Locomotive boiler
b) Marine boiler
c) Mobile boiler
d) Babcock-Wilcox boiler
Answer: d
Explanation: If the boilers are used at one place only they are termed as stationary boilers. These boilers are used for either process heating in industries or for power generation in steam power plants. These are used at central station utility power plants, for plant process etc. Ex: Babcock-Wilcox boiler, Fluidized Bed Combustion boiler.
5. Which of these is a mobile boiler?
a) Lancashire boiler
b) Stirling boiler
c) Locomotive boiler
d) Cochran boiler
Answer: c
Explanation: The boilers, if they are portable, i.e., if they can be moved from one place to other place those are known as mobile boilers. Such boilers are used in locomotives and ships to get the engine moving. And also small units are used for temporary at working sites. Ex: Locomotive boiler, Marine boiler etc.
6. Which type of boiler is it when the furnace is placed in the region of boiling water?
a) Internally fired boiler
b) Externally fired boiler
c) Babcock-Wilcox boiler
d) Stirling boiler
Answer: a
Explanation: If the furnace region is placed in the region of boiling water, the boilers are termed as internally fired boilers. Ex: Lancashire boiler. If the furnace is placed outside the boiling water region, the boilers are known as externally fired boilers. Ex: Babcock-Wilcox boiler.
7. Are boilers defined on the basis of heat source.
a) Yes
b) No
Answer: a
Explanation: Boilers can be classified based on fuel used for combustion or heat generation source. Various heat sources are: heat generated by the combustion of fuel in solid, liquid or gaseous form. Heat generated by hot waste gases as byproducts of other chemical processes. Heat generated by electrical energy and nuclear energy.
8. What is the steam pressure limit of natural circulation boilers?
a) 650bar
b) 180bar
c) 400bar
d) 550bar
Answer: b
Explanation: Water is purely circulated by density difference with most of the heat from the fuel flame being radiated to the water walls directly. The steam pressure of such boilers is limited to about 180bar, with water and steam being separated in the boiler drum.
9. Which type of boilers use orifice to control the flow circulation?
a) Natural circulation boilers
b) Forced convection boilers
c) Once-through boilers
d) Positive forced circulation boilers
Answer: b
Explanation: In these boilers water is circulated by using an additional pump. These boilers often use orifices to control the flow circulation. Orifices are located at the bottom of the tubes that ensure even distribution of flow through water wall tubes. These boilers can generate steam upto about 200 bar.
10. Which of the given boilers operate above critical pressure?
a) Natural circulation boilers
b) Forced circulation boilers
c) Once-through boilers
d) Water tube boilers
Answer: c
Explanation: Once-through boilers operate above critical pressure i.e., above 221.2bar. As the density of water and steam are same above the critical pressure there will be no recirculation. These types of boilers are also called as positive forced circulation boilers.
11. Which type of boilers are called drum-less boilers?
a) Natural circulation boilers
b) Fire tube boilers
c) Positive forced circulation boiler
d) Forced circulation boiler
Answer: c
Explanation: In positive forced boilers, water enters the bottom of the tubes and completely transforms into steam as it passes through the tubes and reaches at the top. Thus, these boilers do not need a steam drum and hence often referred as drum-less boilers. These boilers work at very high pressures.
12. What is the advantage of having smaller ratio of water to steam space?
a) Steam can be generated at a faster even if the boiler is cold
b) Increases the rate of evaporation
c) Water is made cyclic, i.e., from boiler drum to water tube and back to drum
d) Helps in mobilizing the boiler
Answer: a
Explanation: Rate of evaporation is more as area of heating surface is more due to presence of large small diameter tubes. Due to that smaller water ratio is allowed to steam space where in the steam can be generated as a faster rate even if the boiler is cold. As the rate of evaporation is more, it is preferred in steam power plants for power generation.
13. Chances of sediments depositing inside the water tubes in the shell is less due to?
a) Low working pressure
b) Natural circulation of water
c) Partial circulation of water
d) High working pressure
Answer: d
Explanation: Due to high working pressure and positive circulation of water, chances of sediments depositing inside water tubes in the shell is less. This high working pressure of boiler in the shell can withstand high temperature or thermal stresses.
14. Out of the given option choose the advantage that supports fire tube boilers?
a) Water circulation is cyclic
b) Used as a mobile boiler
c) Water circulation is limited inside boiler shell
d) Bursting of flue tube does not cause any explosion
Answer: c
Explanation: Water circulation is limited inside the boiler shell. Water need not be that much pure and needs minimum treatment like passing through a pressure filter. Cleaning and repairing is not easy due to inaccessible parts, furnace cannot be altered and is used for one fuel only.
15. Which are the major types of boilers that are operated in world today?
a) Natural circulation boiler
b) Forced circulation boiler
c) Fire tube boiler
d) Once through boiler
Answer: d
Explanation: The once through boiler has higher load response characteristics due to the fact that it does not have drum and has much lower water inventory. Many times load change response is dictated by the firing system and its controls rather than the boiler, per-say.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Types of High Pressure Boilers – 1”.
1. What type of boiler is a Lamont boiler?
a) Forced circulation
b) Natural circulation
c) Over-through
d) Positive forced circulation
Answer: a
Explanation: A Lamont boiler is a forced circulation water tube boiler. In which the boiler water is circulated through an external pump through long closely spaced tubes of small diameters. The mechanical pump is employed to get an adequate and positive circulation in steam and hot water boilers.
2. What is called as the heart of the Lamont boiler?
a) Water drum
b) Centrifugal pump
c) Furnace
d) Blower
Answer: b
Explanation: A centrifugal pump which forms the heart of the Lamont boiler is responsible to circulate water within the boiler system. It receives water from the drum and delivers it to the distribution header. The numbers of headers may differ in numbers and depends on the size and design of each boiler.
3. Through what is feed water from hot-well is passed through, before entering steam and water drum in Lamont boiler?
a) Evaporator tubes
b) Economizer
c) Distributer header
d) Circulating pump
Answer: b
Explanation: Feed water from the hot well is passed through the economizer tubes before entering the steam and water drum. During its flow through the economizer tubes, water gains maximum sensible heat from the flue gases escaping to the exhaust.
4. In what form are the boiler’s tube arrange in Lamont boiler?
a) parallel in Vertical
b) Inclined vertically
c) parallel in horizontal
d) Horizontally inclined
Answer: c
Explanation: The boiler heating surface includes a number of tubes arranged in a parallel form and the inlet ends are welded to the distributors or the headers. A circulation pressure is to be provided during the installation of the pump as per the boiler design and it should be sufficient to overcome the resistance offered by the tubes.
5. Through which does the even circulation of feed water is possible in Lamont boiler?
a) Nozzles
b) Water trough
c) Feed pump
d) Hose
Answer: a
Explanation: An even circulation of feed water in Lamont boiler takes place with the help of nozzles provided at the inlet of the tubes which create the differential pressure adequate to cover the variations occurring at fluctuating loads or uneven firing conditions.
6. What is the pressure range between which Lamont boilers operates?
a) 80-120bar
b) 120-160bar
c) 180-360bar
d) 450-560bar
Answer: b
Explanation: The Lamont boiler operates between the pressure range of 120-160bar, due to this natural circulation is limited because of density difference between the liquid and vapor. Hence the external centrifugal pump is used to assist the circulation.
7. In which year was Lamont boiler invented?
a) 1905
b) 1910
c) 1920
d) 1925
Answer: d
Explanation: The Lamont boiler was invented by Walter Douglas Lamont in year 1925; He bought the idea from papers to existence. He also introduced the concept of forced circulation boiler. The initial design of Lamont for this boiler confirmed lighter, safer and higher rates of heat transfer.
8. What type of steam is generated by evaporator tube of Lamont boiler?
a) Saturated steam
b) Unsaturated steam
c) Superheated steam
d) Flash steam
Answer: a
Explanation: The steam generated by the evaporator tube of the Lamont boiler is saturated steam. If it is directly used in steam turbine, it can cause the corrosion. So the saturated steam sends to the super heater where it increases the temperature of steam.
9. Where is water steam separator drum located in Lamont boiler?
a) Inside of the boiler
b) Right above the furnace
c) Before the feed water pump
d) Outside of boiler
Answer: d
Explanation: The steam separator is situated outside of the boiler. In this the mixture of water and steam from the evaporator tube is sent, where it separates the steam and sends it to the super heater. The remaining water is again sent to the economizer.
10. What is the main disadvantage of Lamont boiler?
a) Less flexible in design
b) Low heat transfer rate
c) Formation of bubbles
d) Low steam generation capacity
Answer: c
Explanation: The main disadvantage of Lamont boiler is the formation of bubbles. These bubbles come in contact with the inner surface of the heating tubes and subsequently are attached to it. The bubbles attached to the tube surface have higher thermal resistance and consequently reduce the heat flow and steam generation.
11. In which year was Benson boiler was invented?
a) 1918
b) 1920
c) 1921
d) 1922
Answer: d
Explanation: Benson boiler is high pressure, drum less, water tube boiler with forced circulation. This was invented by Mark Benson in year 1922. It was Mark Benson who first proposed the idea to compress the water eat supercritical pressure before heating in boiler.
12. What type of boiler is a Benson boiler?
a) Super critical boiler
b) Fire tube boiler
c) Natural circulation boiler
d) Over-through boiler
Answer: a
Explanation: Benson boiler is a super critical boiler with pressure range of 225bar to 500bar in which the feed water is compressed to a supercritical pressure and this eliminates the formation of bubbles completely, bubbles do not form because at supercritical pressure the density of water and steam becomes same.
13. What is the capacity of Benson boiler?
a) 180 tonnes/hr & above
b) 150 tonnes/hr & above
c) 250 tonnes/hr & above
d) 300 tonnes/hr & above
Answer: b
Explanation: Feed water from the hot-well is forced through the economizer tubes. The hot water enters the radiant section of the evaporator tubs and then passes through convective section of the evaporator tubes. Since the boiler has no drum, thee steam generated in the evaporator enters the super heater tube where it is heated above the critical pressure. So the Steam rising capacity of the boiler is 150 tonnes/hr & above.
14. What is the major disadvantage of the Benson boilers?
a) Boiler is big in size
b) Has large storage capacity
c) Deposition of salts
d) Bubble formation
Answer: c
Explanation: The major disadvantage of the Benson boiler is that when water transforms into steam in the convective section of the evaporator, salts are deposited in the transformation zone. Hence periodic flashing of evaporator tubes in the convective section is necessary.
15. Why starting valve is closed and valve 2 is opened while taking boiler on range in Benson boiler?
a) Avoid excessive heating of tube
b) To maintain the constant flow of water
c) To avoid pressure built up in tubes
d) To avoid pipe leakages at joints
Answer: a
Explanation: The boiler is started from cold by circulating the feed water from the hot well by operating the starting valve. While taking the boiler on range, starting valve is closed and valve 2 is opened. This method avoids excessive heating of tubes.
This set of Energy Engineering test focuses on “Types of High Pressure Boilers – 2”.
1. Which of the given boilers velocity of flue gases is greater than velocity of sound?
a) Benson boiler
b) La-Mont boiler
c) Schmidt-Hartmann boiler
d) Velox boiler
Answer: d
Explanation: Velox boiler is a forced circulation water tube boiler. In this boiler, the velocity of the flue gas is greater than the velocity of sound, which causes more heat transfer from gas to the water, which increases the steam generation rate. It is mostly used in gas turbine. Due to this reason it is one of the important boilers.
2. Which boiler is most successful boiler in the gas turbine industries?
a) Because it has greater flexibility
b) It is easy to control, it’s fully automatic
c) It has higher thermal efficiency of all
d) Can increase heat transfer without changing its size
Answer: d
Explanation: When the velocity of gas is greater is greater than speed of the sound, its heat transfer rate also increases. More heat is transferred from the gas to water comparatively when the heat transfer is at subsonic speed. This boiler can increase the heat transfer or can say steam generation rate without increasing boiler size. This is why; Velox boiler is most successful boiler in the gas turbine industries.
3. What is done to increase the rate of heat transfer in the Velox boiler?
a) The boiler is heated upto very high range of temperature
b) The size of the boiler is changed as it is flexible
c) High grade fuel is made use for the combustion
d) Combustion gases are circulated through tubes with supersonic speed
Answer: d
Explanation: This boiler uses oil or gaseous fuel inside furnace for its combustion. The combustion gases are circulated through the tubes with supersonic speed velocity to increase the heat transfer rate between the hot gases and feed water.
4. What type of boiler is a Velox boiler?
a) Forced circulation boiler
b) Natural circulation boiler
c) Positively forced circulation boiler
d) Once- through boiler
Answer: a
Explanation: Velox boiler is a forced circulation boiler. It has gas turbine driven air compressor, which compresses the air. This compressed air enters into the vertical combustion chamber; as a result, high rate of heat is released from the fuel, which increases the flue gas velocity up to the sound velocity. In this boiler pump is used to circulate water inside tube.
5. What is used to heat the feed water which is used for recirculation through tubes?
a) Condenser
b) Pre-heater
c) Economizer
d) Water Clarifier
Answer: c
Explanation: The combustion gas coming out of the super heater is used to run gas turbine which runs at air compressor. The exhaust gases coming out of the gas turbine are passed through the economizer to heat the feed water. Feed water is recirculated with the help of a pump.
6. How many circuits are there in the Schmidt-Hartmann boiler?
a) 3
b) 2
c) 4
d) 6
Answer: b
Explanation: There are 2 circuits in S-H boiler, in the primary circuit distilled water from the water drum passes through the primary evaporator and steam produced is passed over drum and in secondary circuit, feed pump supplies impure water from hot well to the evaporator drum through feed preheater.
7. Which type of circulation is incurred in Schmidt-Hartmann boiler?
a) Natural circulation
b) Positive forced circulation
c) Forced circulation
d) Once-through circulation
Answer: a
Explanation: Natural circulation is used in the primary circuit of a Schmidt-Hartmann boiler and this is sufficient enough to affect the desired rate of heat transfer and to overcome the thermo-siphon head of height about 2 to 10 meters. This boiler has got 2 pressure cycles.
8. Why pressure gauge and safety valve are made use of in the Schmidt-Hartmann boiler?
a) Safety against fire causes
b) To control the burst/blast of the boiler due to variance in pressure
c) Safe guard against leakage accidents
d) Act as controller against overheating of water in the boiler and boiler tubes
Answer: c
Explanation: In normal circumstances, replenishment of distilled water in the primary circuit is not required as every care is taken in the design and construction to prevent leakages. But as a safeguard against leakage accidental loss, a pressure gauge and safety valve are fitted in the Schmidt-Hartmann boiler’s circuit.
9. Why are salts deposited on the evaporator drum?
a) Due to continuous circulation of water
b) Due to usage of hard water containing calcium content
c) Due to circulation of impure water
d) Due to the chemicals added in water
Answer: c
Explanation: The salts are deposited in the evaporator drum due to the circulation of impure water can be easily cleaned by blowing off the water with pressure or by removing the submerged coil from the drum.
10. Overheating doesn’t occur in components of primary circuit Schmidt-Hartmann boiler.
a) True
b) False
Answer: b
Explanation: There is a rare chance of overheating or the burning of the highly heated components of the primary circuits there is no danger of salt deposition as well as there is no chance of interruption to the circulation either by rust or any other material. The highly heated parts run safe throughout the life of the boiler.
11. What is feature of the Loffler boilers?
a) Evaporating water by super heated steam
b) Provide better efficiency by re-circulating gas coming out of turbine
c) Produce better steam quality by heating the boiler furnace above critical degrees
d) Eliminate the extra components used
Answer: a
Explanation: The novel feature of the Loffler boiler is to evaporate water solely by means of superheated steam. The furnace heat is supplied only to economizer and super heater. In other words, steam is used as a heat absorbing medium.
12. What is the major difficulty of the La-Mont boiler?
a) Unstable water circulation
b) Deposition of salts
c) Overheating of the components
d) Boiler working is slow
Answer: b
Explanation: Major difficulty experienced in La-Mont boiler is deposition of salt and sediment on the inner surfaces of water tubes. The deposition reduces the heat transfer, ultimately, the generating capacity. This difficulty was solved by Loffler boiler by preventing the flow of water into the boiler tubes.
13. At what temperature is the water in convection super heater is heated of Loffler boiler?
a) 200 o C
b) 300 o C
c) 400 o C
d) 500 o C
Answer: d
Explanation: Steam coming out of the radiant super heater enters the convection where it is finally heated to the desired temperature of 500°C. The convection superheater receives heat from the flue gases entered by convective heat transfer. Both radiant and convective super heaters are arranged in the series in the path of flue gases.
14. Which is the most recent economical method of power generation from boilers?
a) Natural circulation boiler
b) Fire tube boiler
c) Forced circulation
d) Super critical boiler
Answer: d
Explanation: Varying fuel costs have constantly persuaded power engineers to search for more economical methods of power generation. The most recent method is super critical boiler which operated at pressure of 3200 psi or 22 Mpa therefore facilitates in converting water into steam instantly.
15. Which of the following boilers has the highest heat transfer capacity?
a) Subcritical boiler
b) Critical boiler
c) Forced circulation boiler
d) Supercritical boiler
Answer: d
Explanation: The heat transfer rates of supercritical boilers are large compared to any other boilers. The steam side heat transfer of subcritical is 165000 kJ/m 2 hr o c when the steam pressure and temperature are 180 bar and 538 o C whereas, the steam side heat transfer coefficients of supercritical boiler is about 2,20,200 kJ/m 2 hr o C when the steam is generated at 240 o C.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Draught System – 1”.
1. Why boiler draught is most essential part of the thermal plants?
a) Serves combustion by supplying ample amount of air
b) Helps in maintaining air ventilation
c) Required to maintain constant air flow
d) Stabilizes the boiler system
Answer: c
Explanation: Boiler draught is the difference of pressure required to maintain constant flow of air into the furnace and to discharge the flue gases to the atmosphere through a chimney. Thus boiler draught is one of the most essential systems of thermal plant. Boiler draught is generated by using chimney, fan, steam jet or air jet or combination of them.
2. Which is the correct formula of total draught loss?
a) H t = H v + H b + H c + H cd
b) H t = H v + H b – H c + H cd
c) H t = H v – H b + H c + H cd
d) H t = H v – H b – H c – H cd
Answer: a
Explanation: The total draught required to produce the current of the air and to expel the flue gases is given as follows.
Total draught loss = Velocity head loss at the chimney exit + fuel bed resistance + head loss in
Equipment’s like economizer, air heater etc. + head loss in chimney and ducts
i.e., H t = H v + H b + H c + H cd
3. By what is natural draught produced?
a) Air duct
b) Chimney
c) Locomotive exhaust
d) Air blower
Answer: b
Explanation: Natural draught is produced by using a chimney. A chimney is a vertical tubular structure made up of brick, steel or reinforced concrete. The draught produced by the chimney is due to the difference in temperature of hot flue gases inside the chimney and the atmospheric air.
4. Which of the following given below as the affect on amount natural draught?
a) Boiler operation
b) Size of the furnace
c) Grade of the fuel
d) Dust content in the fuel is used
Answer: a
Explanation: The draught produced in the chimney is due to the temperature difference of the hot flue gases. In addition to this, height of the above the furnaces grate, whether conditions and boiler operations also have considerable effect on the amount of natural draught.
5. When is artificial draught preferred?
a) When quick evacuation of flue gases is required
b) When we choose large power plant systems
c) When draught produced by chimney is not sufficient
d) When there are many components inside the boiler
Answer: c
Explanation: This type of draught is preferred when draught produced by the chimney is not sufficient or when a certain draught is to be maintained irrespective of atmospheric temperature. Artificial draught as no flexibility, as poor efficiency and requires tall chimney.
6. Artificial draught is also called as _______
a) Force draught
b) Induced draught
c) Balanced draught
d) Mechanical draught
Answer: d
Explanation: In modern high pressure boilers, use of economizers, super heaters, air pre heaters reduces the exit flue gas temperature considerably. This results in increased chimney height, whose cost is not justified. By using mechanical draught chimney height is considerably reduced.
7. What is installed to transfer air into furnace in forced draught system?
a) Air blower
b) Tuyeres
c) Draft gauges
d) Cyclone separator
Answer: a
Explanation: In force draught system an air blower is installed near the boiler which blows into the furnace. The pressure of air throughout its path is above atmospheric pressure. This system also uses chimney to discharge hot flue gases into the atmosphere.
8. Where is blower installed in induced draught system?
a) Near the boiler
b) Base of the chimney
c) Above the boiler
d) Between economizer and air preheater
Answer: b
Explanation: In induced draught system the blower is installed near the base of the chimney so as to facilitate sucking of flue gas from the furnace. Thus pressure inside the furnace is reduced below atmospheric pressure inducing outside air into the furnace.
9. How can exhaust gas be recovered in the induced draught?
a) By installing the forced draught fan at the starting point
b) By extending the chimney’s height
c) By inletting high amount of air from multiple air ducts
d) By installing air preheater and economizer along the gas path
Answer: d
Explanation: The heat in exhaust gases can be recovered as much as possible by installing an air preheater and economizer along the gas flow path. As the draught produced in this system is independent of flue gas temperature care should be taken such that the fan handles gas at its lowest possible temperature.
10. Which is most preferred type of draught system?
a) Chimney draught
b) Fan draught
c) Force draught
d) Balanced draught
Answer: d
Explanation: A balanced draught system combines the features of forced draught and induced draught. In case of forced draught, when the furnace doors are opened high pressure air rushes outside and even blow out the fire entirely. In case of induced draught, when the furnace doors are opened to atmosphere air enters the furnace and causes imbalance in the draught. This difficulty is overcome by using balanced draught.
11. How pressure in the furnace is maintained below atmospheric pressure in balanced draught system?
a) By forced draught fan
b) By induced fan
c) Depends on the height of chimney
d) By installing Natural draught
Answer: b
Explanation: In balanced draught system, a forced draught fan is installed near the boiler which helps in overcoming the resistance of fuel bed by supplying sufficient air for combustion. An induced draught fan is installed near the chimney base removes the flue gases coming from the furnace and maintains pressure in the furnace slightly below the atmospheric pressure.
12. Which type of draught system is used in the locomotives?
a) Natural draught system
b) Balanced draught system
c) Forced draught system
d) Induced Steam draught system
Answer: d
Explanation: Induced steam draught system is used in a boiler for a locomotive. When the locomotive is stationary steam generated in the boiler is fed to the smoke box through the nozzle to create the draught. When locomotive is moving air enters through the dampers and makes its way through grate and smoke box.
13. Which draught system is also known as turbine draught?
a) Forced steam draught
b) Induced steam draught
c) Natural draught
d) Fan draught
Answer: a
Explanation: Forced steam draught system is also is known as turbine draught. In this case, steam from the boiler is throttled to a pressure of 1.5 to 2 bar and passed through a series of nozzles fitted to a diffuser pipe.
14. Which draught system is used as conjunction with chimney draught?
a) Forced steam draught
b) Forced draught
c) Induced draught
d) Balanced draught
Answer: a
Explanation: The high velocity steam coming out from the nozzle drags the air column along with it creating suction. The kinetic energy of air and steam mixture is converted into pressure energy forcing air through the coal bed to the furnace. So, Forced steam draught is used as a booster in conjunction with chimney draught.
This set of Energy Engineering Quiz focuses on “Draught System – 2”.
1. Which is the net pressure equation used to find chimney height?
a) P = H (W a -W g )
b) P = H (W a +W g )
c) P = H (W g -W a )
d) P = H
Answer: a
Explanation: The pressure acting on the grate from chimney side,
P 1 = P a + W g H
Pressure acting on the grate from atmospheric side
P 2 = P a + W a H
Where, P a = Atm pressure
W a = weight density of air
W g = Weight density of hot gases
energy-engineering-questions-answers-quiz-q1a
The net pressure acting on the combustion chamber due to the pressure exerted by gas column and air column is given by
P = P 2 – P 1 (as W a > W g )
P = (p a + W a H) – (P a + W a H)
P = H (W a – W g )
This pressure difference is known as static draught and is responsible for causing the flow of air through the chimney.
2. Which is the equation used to find chimney diameter?
a) D = 1.128\
D = 5.48\
D = 5.48\
D = 1.128\(\sqrt{\frac{ρg V}{Mg}}\)
Answer: a
Explanation: The mass of gases flowing through any cross section of the chimney is given by
energy-engineering-questions-answers-quiz-q2a
3. The portion of flue gases carried away to produce draught could be utilized to _______
a) Heat the air entering furnace
b) Blow out the combustion products such as soot and ash
c) Heat the fuel in ash chamber
d) Support the combustion
Answer: a
Explanation: It is evident that the draught is created at the cost of thermal efficiency of boiler plant installation since a portion of flue gases carried away by the flue gases to produce the required draught could have been used either in heating the air entering the furnace or in heating the feed water, which would increase the thermal efficiency.
4. Determine the height of chimney above grate level. Where diameter of chimney is 1.75m and produces a draught of 1.8cms of water. Temperature of flue gases is 290 o C. The flue gases formed per kg of fuel burnt are 23kg. Neglect the losses and assume atmospheric temperature as 20 o C?
a) H = 23.28m
b) H = 18.56m
c) H = 32.77m
d) H = 41.92m
Answer: c
Explanation: Given: D = 1.75m,
Draught in mm of water = 1.8cm = 18mm
Flue gas temperature = Tg = 290 o C = 563K
Ambient temperature = Ta = 20 o C = 293k
Flue gases formed per kg of fuel burnt: (m a + 1) = 23kg
energy-engineering-questions-answers-quiz-q4
5. A draught of 15mm of water is produced by using a chimney of height 30m. The ambient air and flue gases are at 27 o C and 300 o C respectively. The coal burned on the grate contains 81% carbon, 5% moisture and remaining ash. Neglect the losses and assume values of burnt products equivalent to the volume of air supplied and for the complete combustion of fuel, find the percentage of excess of air supplied?
a) 14.56%
b) 52.89%
c) 8.13%
d) 20.002%
Answer: c
Explanation: Given: Draught in mm of water = 15mm
Height of chimney = 30m
Ambient temperature, Ta = 27 + 273 = 300K
Flue gas temperature, Tg = 300 + 273 = 573K
% of carbon = 81%
energy-engineering-questions-answers-quiz-q5
6. Determine the height of the chimney to produce a static draught of 22mm of water if the mean flue gas temperature in chimney is 290 o C and ambient temperature in boiler house is 20 o C. The gas constant for air is 29.26Kgm/Kgk and for chimney flue gas is 26.2 Kgfm/Kgk. Assume reading as 760mm of mercury?
a) 38.42m
b) 42.55m
c) 45.84m
d) 44.03m
Answer: b
Explanation: Density of air at 290K ρ g = P/RT = [1.033 * 10 4 / 29.26 * 290] = 1.217Kg/m 3
Density of fuel gas at 563K, ρ g = [1.033 * 10 4 / 26.2 * 563] = 0.7 Kg/m 3
Static Draught, p = H (ρ a – ρ g )
22 = H
H = 42.55m
7. The flue gases of natural draught are at higher temperature when compared to flue gases in artificial gas.
a) True
b) False
Answer: a
Explanation: The flue gases of natural draught are at higher temperature when compared to flue gases of artificial gas because to maintain certain minimum temperature required to produce a given draught for the given height of the chimney. Due to higher flue gas temperature, the heat lost with flue gases is more in natural draught.
8. Determine the height of the chimney to get net draught of 12mm if the total losses are 4mm. the temperature of air is 25 o C and the temperature of chimney gases is 300 o C. The mass of air used per kg of fuel used is 18kg. One kg of air occupies a volume of 0.7734m 3 at normal temperature?
a) 26.84
b) 20.22
c) 29.93
d) 18.09
Answer: c
Explanation: Density of air at normal temperature = 1/0.7734
= 1.293Kg/m 3
Density of air at 298K, ρ a = 1.293 × 273/298
= 1.1845 Kg/m 3
Density of gases at 573K, ρ g = 1.293 × /18) × 273/573
= 0.65 Kg/m 3
But, P = 12 + 4
= 16 mm of water
P = H (ρ a – ρ g )
16 = H
H = 29.93m
9. A 15kg of air is supplied per kg of fuel burnt to the combustion chamber of a boiler using fuel 600kg/hr. the temperature of flue gases and ambient air are 273°C and 32°C. If the minimum draught required to start the flue is 9.5mm of water, find out the minimum height of the chimney?
a) 22.66m
b) 23.84m
c) 24.52m
d) 25.16m
Answer: a
Explanation: Temperature of fuel gases T g = 237 + 273 = 510K
Temperature of ambient air T a = 32 + 273 = 305K
Drought in mm of water H w = 9.5mm
Mass of air m g = 15kg
We have,
energy-engineering-questions-answers-quiz-q9
10. Using which of the given formula the chimney height is calculated to get the answer of 67.4m when the coal burnt is 18.8TPH and considering 0.5% of sulfur content in coal?
energy-engineering-questions-answers-quiz-q10
a) H = 12 13
b) H = 17 13
c) H = 14 13
d) H = 22 13
Answer: c
Explanation: Given: Coal = 18.8TPH = 18800kg/hr
Sulfur = 5%
energy-engineering-questions-answers-quiz-q10a
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Environmental Aspects of Power Generation”.
1. Power generation facilities have been affected by the concern for the _______
a) Environment
b) Availability of resources
c) Soaring costs
d) Humans
Answer: a
Explanation: The design, location, construction and operation of electrical power generation facilities have been affected by the concern for the environment. Hence power engineer must have concern for the environment while producing enough power to meet public demand at low cost. Government has passed environmental legislation that limits amount of pollutants that can be discharged to the environment.
2. How many forms of sulfur exist in the atmosphere?
a) 1
b) 2
c) 3
d) 4
Answer: c
Explanation: Sulfur in the atmosphere exists in three forms:
i. Sulfur dioxide, SO 2 which comes from artificial causes.
ii. Hydrogen sulfide, H 2 S which comes from natural causes.
iii. Various sulfates, coming from sea spray and oxidation of SO 2 .
3. How much amount of sulfur dioxide is caused in the atmosphere?
a) SO 2 <25%
b) 50% <SO 2 >50%
c) 0%
d) SO 2 >50%
Answer: a
Explanation: Although sulfur dioxide is caused by artificial causes, it is primary concern since it contributes <25% of all sulfur in the atmosphere. It is estimated that more than 90 million tons of sulfur dioxide are discharged into the atmosphere every year.
4. Acid rain is caused mainly by ___________
a) methane gas
b) sulphuric acid
c) sulfur dioxide
d) carbon dioxide
Answer: c
Explanation: Acid rain and acid snow are caused by mainly by sulfur dioxide and also oxides of nitrogen and other sulfur oxides contribute fewer amounts to it. These gasses carried along wind currents combine with water molecules in the water vapor of the atmosphere, forming tiny drops. These drops when encountered by snow or rain producing clouds, results in acid rain.
5. Acid rain affects tree and plants.
a) True
b) False
Answer: a
Explanation: Acid rain does affect trees and plants. It results in leaching of essential plants nutrients from the soil and reduces nitrogen fixation by microorganism. This makes soil less fertile. Also dissolve aluminum and cadmium out of soil minerals, allowing them to enter roots and kill trees.
6. By what type of reaction are Nitrogen oxides caused?
a) Endothermic reaction
b) Combustion reaction
c) Exothermic reaction
d) Synthesis reaction
Answer: a
Explanation: Production of nitrogen oxides is an endothermic reaction and its concentration is temperature dependent. NO x emissions can be reduced by lowering the combustion temperature and by eliminating hotspots in the furnace.
7. Which among the following oxides are major contaminants in the atmosphere?
a) Nitrogen oxides
b) Oxides of carbon
c) Sulfur oxides
d) Particulate matter
Answer: b
Explanation: Oxides of carbon such as CO, CH 4 and CO 2 are major contaminants in the atmosphere. Carbon monoxide is caused by natural causes partially, such as marsh gas, coal, vegetation and forest fires. This contribution is small compared to human generated causes. 90% of CO is produced by motor vehicles, where as power plants contribute less than 1%. The total amount of CO produced per year is 230 million tones.
8. Carbon dioxide (CO 2 ) is largely contributed by __________
a) vehicles
b) power plants
c) humans
d) plants
Answer: b
Explanation: Carbon dioxide is largely contributed by power plants. CO 2 added to nature by natural causes viz., decay of organic matter contributes more than that by artificial causes. Also CO 2 contaminants in atmosphere are not considered as pollutants as it is essential for plants.
9. By which process can CO 2 be removed from the atmosphere?
a) Pyrolysis
b) Photosynthesis
c) Filtration
d) Magnetohydronomics
Answer: b
Explanation: Carbon dioxide (CO 2 ) can be removed by the process of photosynthesis. This process concerts back CO 2 into oxygen and organic compounds in the presence of sunlight and water. However, more concentration of CO 2 results in green house effects.
10. What causes green house effect?
a) Carbon dioxide
b) Carbon tetra oxide
c) Oxygen
d) Nitrogen
Answer: a
Explanation: CO 2 causes green house effect. The concentration of CO 2 has increased to a level beyond the capacity of plant life and the oceans to completely remove it. 50% of CO 2 added is retained in the atmosphere. And this retained CO 2 causes green house effect.
11. In what form are the radiations coming from sun?
a) Long waves
b) Short waves
c) Transient waves
d) Longitudinal waves
Answer: b
Explanation: The atmosphere, analogous to the glass panes of green house, transmits the radiation from the sun. The surface of sun is about 6000k and most of the radiation is in the form of short waves and visible portions of the spectrum, and only a portion of the radiation is absorbed or scattered back to the space by atmosphere.
12. What causes absorption of infrared radiations?
a) Large contents of CO 2 and H 2 O
b) Sulfur oxides
c) Ozone
d) Earth gravity
Answer: a
Explanation: The presence of CO 2 and H 2 O in the atmosphere results in the absorption of large portions of infrared radiations from the surface and partial of those radiations back to earth. Thus atmosphere us not transparent completely to the reradiated energy and traps much of the energy from the sun.
13. What is the reason for melting of polar caps?
a) Increasing levels of sulfur
b) Depletion of ozone
c) Increasing levels of CO 2
d) Longitudinal radiation
Answer: c
Explanation: The growing levels of concentration of CO 2 increase the surface temperature of earth. This may result in climatic changes with disastrous consequences, such as melting of polar ice caps and rising of sea levels.
14. What are the constituents of particulate matter?
a) Fluid gases
b) Smoke and dust
c) Flue gas
d) Poisonous gases
Answer: b
Explanation: Particulate matter is composed of smoke, and other solids of variety of organic and materials. Both natural and human activities are responsible for the particulate matter in the atmosphere. These are the basic causes for the formation of smog and fog.
15. What is TDI stands for in the Thermal pollution field?
a) Turbocharger direct injection
b) Toluene Diisocyanate
c) Thermal energy discharge integration
d) Thermal discharge index
Answer: d
Explanation: To compare power generating systems with respect to the amount of thermal energy discharged to the environment a term is introduced, known as thermal discharge index . The thermal discharge index of any power system is the number of thermal energy units discharged to the environment of each unit of electrical energy produced by plant.
This set of Energy Engineering MCQs focuses on “Ash and its Effects on Boiler Operation and Performance”.
1. Ash is widely used in the production of _______
a) Plastics
b) Thermal wear
c) Food oxidants
d) Cement
Answer: d
Explanation: Ash is widely used in the production of cement. Fly ash is pozzolanic and develops self hardening characteristics. Concrete made of ash can yield improved workability and strength greater than all cement based concrete. The pozzolanic quality of ash lime mixture creates a healing of cracks in the pavement themselves.
2. Why is used for treating acidic soils?
a) To improve fertility of soil
b) For their better alkali values
c) To keep away insects
d) To loosen up the soil
Answer: b
Explanation: Due to their better alkali values, they are used for treating acidic soils. Its use for agricultural purposes is recently experimented in Japan and it is found that it supplies essential nutrients as sulfur, boron, calcium and zinc. It also adjusts pH to optimum levels for plant growth.
3. What is the India’s current total capacity of power plants installed?
a) 84000MW
b) 92000MW
c) 28000MW
d) 150000MW
Answer: a
Explanation: India’s current total installed capacity of power plants is 84000MW, out of which coal-fired thermal plants contribute 54000MW . The World Bank estimated coal based power generation to increase by another 81000MW by 2010 which would have further increased fly ash load of 56 million tons per year.
4. How much percent of fly ash is, mixed with Portland cement?
a) 10 to 25%
b) 5 to 10%
c) 30 to 50%
d) 50%
Answer: a
Explanation: 10 to 25% dry fly ash can be used as during manufacture of cement or blended with finished Portland cement to produce Portland pozzolana cement whose strength is higher. The major drawback of this cement is its high cost and it requires more setting time.
5. Sintered light weight aggregates are produced by which method?
a) Nodulisation
b) Autolysation
c) Decondensation
d) Patronisation
Answer: a
Explanation: Sintered light weight aggregates are produced by nodulisation of fly ash and sintering them at 1000 o c to 1300 o C. Unburnt fuel in the fly ash modules supports ignition. Sintered weight aggregate substitute’s chips in concrete reducing dead weight.
6. How much time period is fly ash stone powder cement bricks water cured?
a) A week
b) 2 weeks
c) 3 weeks
d) 1 month
Answer: d
Explanation: Fly ash stone powder cement bricks are manufactured by mixing weighted fly ash, cement and stone powder in a mixture and molded and pressed in brick making machine. The compacted bricks are water cure for a month. The compressive strength of these bricks varies from 70 to 110 bar depending upon cement content.
7. How much amount of fly ash is made utilized by India?
a) 3 – 4%
b) 10 – 20%
c) 50 – 60%
d) 35 – 55%
Answer: a
Explanation: About 20% of coal ash in the coal is converted into bottom ash and 80% fly ash. India utilizes only 3 – 4% of fly ash generated as compared to 40% utilization in France and U.K. The government 5t of India is imposing to achieve about 50% of fly ash in the upcoming years.
8. Which among the following when utilized gives good finishing on the both sides of the walls?
a) Cast-in-situ fly ash walls
b) Cellular light weight concrete
c) Sintered light weight aggregates
d) Fly ash cement putty
Answer: a
Explanation: Using high fly ash comprising of cement, lime fly ash and sand in appropriate proportions depending upon the quality of fly ash with pre-measured water cement ratio, cast-in-situ can be built. These can be cast to any thickness using steel shuttering. By using this system we can achieve 20% of economy, quicker construction, good finish on both sides of wall and more carpet area.
9. Which type of concrete is useful in high rise construction?
a) Cellular light weight concrete
b) Cast-in-situ fly ash
c) Fly ash stone powder bricks
d) Sintered light weight aggregates
Answer: a
Explanation: Cellular light weight cement can be manufactured by a process involving the mixing of fly ash, cement, coarse sand fine and a foaming agent. The slurry formed is poured in moulds and allowed to set. The blocks are then removed and cured by spraying water on the stack. The blocks are especially useful in high rise construction reducing the dead weight of the structure.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Cooling Ponds and Towers”.
1. Open cooling system is also called as ____________
a) parallel system
b) once through system
c) air based system
d) non-reversible system
Answer: b
Explanation: Open system is also called as once through system, in this system the water is drawn directly from the upstream side of the river pumped through the condenser and discharged to the downstream side of the river at temperature 5 to 10°C in excess of inlet temperature.
2. How many number of spray nozzle does each module on spray pond cooling system contains?
a) 1
b) 2
c) 3
d) 4
Answer: d
Explanation: Modules in spray pond cooling system contain 4 spray nozzles. The surface area of contact of water is increased when it is sprayed in air. Cooling occurs due to the evaporation of water vapours as the spray propels upwards and falls down to the surface.
3. Which of the following is the simplest method of cooling the condenser water?
a) Spray cooling pond
b) Cooling tower
c) Indirect air cooling
d) Hyperbolic cooling tower
Answer: a
Explanation: Spray cooling pond is the simplest method of all. The hot water coming out of the condenser is sprayed through the nozzles to expose maximum surface area of water to air for effective cooling. The spray ponds are surrounded with wooden walls to prevent the wind from carrying the water particles.
4. In which type of cooling pond system are nozzles arranged on same elevation?
a) Single deck system
b) Double deck system
c) Natural Flow system
d) Direct flow system
Answer: a
Explanation: In a single deck system spray nozzles are arranged at the same elevation. Its effective cooling effect is less than double deck system. Hot water is sprayed through the spray nozzle in air. Cooling occurs due to the evaporation of water vapors at the spray propels and falls down the surface.
5. In which type of cooling system are nozzles arranged on different elevation?
a) Single deck system
b) Double deck system
c) Natural Flow system
d) Direct flow system
Answer: b
Explanation: In double system of cooling ponds the spray nozzles are arranged at different elevations. Cooling effect is more than single deck cooling system as water comes in contact with air at lower temperatures.
6. What are used in the direct flow system to transverse the pond before uniting at intake?
a) Separators
b) Filters
c) Baffle walls
d) Porous pipes
Answer: c
Explanation: In direct flow system the hot water coming out of the condenser enters the middle channel. On reaching the far end it is divided into two currents being directed by the baffle walls so as to transverse the pond several times before uniting at intake point.
7. Select the disadvantage of cooling pond out of the given?
a) The area required of cooling in a cooling pond is small
b) Spray losses due to evaporation and windage run high
c) There is no control over the temperature of cooled water
d) The cooling efficiency is low compared with cooling water
Answer: c
Explanation: The cooling effect is reduced with the decrease in wind velocity and if the load on the plant increases, the pond does not respond to the requirement. When the maximum cooling is required during increased load, it provides minimum cooling in absence of wind flow.
8. What type of cooling system is used in the large power plants?
a) Cooling ponds
b) Natural flow system
c) Cooling towers
d) Single deck system
Answer: c
Explanation: In large power plants cooling towers are used in the place of cooling ponds. A cooling tower is a wooden or metallic rectangular structure, with packed baffling devices. The hot water is delivered to the top of tower and is made to fall down the tower and is broken into small particles while passing over the baffling devices.
9. How does outside air enter into the wet cooling system?
a) Air vents
b) Louvers
c) Tuyeres
d) Vacuum
Answer: b
Explanation: Air and water are thoroughly mixed by fill as water splashes down from one fill level to the next due to gravity outside air enters the tower through louvers from the side of the tower. The heat and mass transfer between water and air is enhanced due to intimate mixing.
10. How is water circulated throughout the dry cooling tower system?
a) Finned tubes
b) Metal pipes
c) Porous tubes
d) Swirling tubes
Answer: a
Explanation: In dry cooling tower circulating water is passed through finned tubes over which cooling air is passed. Heat is rejected to air in the form of sensible heat. A dry cooling tower may be either natural draft type or forced draft type. These types are cheap than wet types of cooling tower.
11. Why is exhaust steam coming out of turbine is admitted to a steam header?
a) To increase the pressure
b) To decrease the velocity
c) To decrease the pressure drop
d) To control the pollution
Answer: c
Explanation: Exhaust steam from turbine is admitted to a steam header in order to minimize the pressure drop. Steam gets condensed as it passes down through the finned tubes arranged in parallel rows.
12. In which system is Cooling of hot water is done on tray as step by?
a) Mechanical draught cooling system
b) Hyperbolic cooling tower
c) Atmospheric cooling tower
d) Wet cooling tower
Answer: c
Explanation: In atmospheric cooling tower, the hot water is delivered at the top most trays and it falls down from one tray to another until it reaches the tank below the tower. The water is cooled by air flowing across the tower.
13. How does the flow of air occur in natural draught cooling towers?
a) Natural pressure head density between cold outside air and humid inside air
b) Variation in pressure of both cold outside air and humid inside air
c) Due to the given air vents and vacuum ports
d) Because of difference in the volume of both the of airs
Answer: a
Explanation: In natural draught cooling tower, the flow of air occurs due to the natural pressure head caused by density difference between the cold outside air and hot humid air inside. The disadvantage of natural draught cooling system is that, to produce to produce large draught the tower should be very high.
14. How is air produced in mechanical draught cooling tower?
a) Air Tuyeres
b) Propeller fans
c) Air blowers
d) Louvre
Answer: b
Explanation: In mechanical draught cooling tower the draught of air id produced mechanically by means of propeller fans. This increases the cooling rate by increasing the air velocity over the wet surfaces and through the tower. These two towers give higher efficiency; reduce spray and windage losses and less ground area.
15. Why is induced draught considered better than the forced draught?
a) Because power requirement is high for forced draught
b) Maintenance of induced draught fan is costlier
c) Forced draught is less efficient
d) Forced draught produces less amount of speed of air
Answer: a
Explanation: Induced draught is considered to be better than forced draught because, the power requirement is high for forced draught and the maintenance of fan is costlier. The induced draught occupies less space ass the fan drives are placed at the top of the tower, the cooling effect is distributed across the entire cross section of the tower.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Boiler Mounting Accessories – 1”.
1. How many level indicators are there in the water level indicator of a boiler?
a) 1
b) 2
c) 3
d) 4
Answer: b
Explanation: The function of the water level indicator is to indicate the level of water inside the boiler drum at any given instant. Two water level indicators are fitted at the front of the boiler drum. The boiler operator keeps track of water level in the drum and operates the feed pump as per the requirement to maintain a constant level of water inside the drum.
2. What is the function of pressure gauge in the boiler?
a) To indicate steam pressure
b) To indicate water pressure
c) To indicate Air pressure
d) To indicate Flue gas pressure
Answer: a
Explanation: The function of the pressure gauge is to indicate the steam pressure inside the boiler drum in bar or in Kgf in cm 2 or in KN/m 2 in gauge pressure. If the boiler is fitted with a superheater, one more pressure gauge fitted to the superheater header indicates the superheated steam pressure at any given instant.
3. other than Steam stop valve in the boiler which is the other similar type of valve used?
a) Non-reversible valve
b) Transient valve
c) Reversible valve
d) Junction valve
Answer: d
Explanation: Stop valve and junction valve are essentially same. Conventionally stop valves are smaller in size whereas, junction valves are larger. When the valve is mounted on the top most portion of the steam drum, normally the valve is called junction valve. If it is connected in the steam pipe to regulate the flow of steam, the valve is known as stop valve.
4. What type valve is a feed check valve of a boiler?
a) One way valve
b) Globe valve
c) Reversible valve
d) Disc check valve
Answer: a
Explanation: Feed check valve regulates the flow of feed water under pressure to the boiler drum. It is essentially a one way valve and allows water to flow only in one direction i.e., towards the boiler drum. No water flows back to the boiler drum.
5. What is the function of Blow down valve of a boiler?
a) To remove sludge
b) To build sediments
c) To remove Flue gas
d) To remove ash
Answer: a
Explanation: Blow down valve is also called as Blow-off-cock. The function of this valve is to remove the sludge or sediments collected at the bottom of the boiler drum from time to time. Whenever boiler cleaning and inspection is due, water inside the tubes and in the boiler drum can be completely drained by operating the blow down valve.
6. What is the function of fusible plug in the boiler?
a) Protect the fire tube
b) To trip on overload
c) To act as a junction switch
d) To maintain pressure
Answer: a
Explanation: The function of the fusible plug is to protect the fire tube from burning due to excessive heating. This usually happens when the water level inside the drum becomes too low and the shell and crown plate are directly exposed to steam space.
7. What is the function of safety valves in the boiler?
a) To prevent excessive steam pressure
b) To prevent excessive air pressure
c) To prevent water pressure
d) To prevent from rising temperatures
Answer: a
Explanation: The function of safety valve is to prevent the excessive steam pressure inside the boiler drum exceeding the design pressure. When the pressure inside the boiler drum exceeds the rated pressure, safety valve automatically opens and discharges the steam to the atmosphere till normal working pressure is retained.
8. How many types of safety valves are used in boiler in practice?
a) 1
b) 2
c) 3
d) 4
Answer: b
Explanation: Two types of safety valves are used in practice
i) Spring loaded safety valve
ii) Dead weight safety valve
9. What happens due to high temperature of feeds water in the economizer?
a) Fuel consumption increases
b) Fuel mechanical efficiency increases
c) Fuel consumption decreases
d) Fuel mechanical efficiency decreases
Answer: c
Explanation: Function of the economizer is to recover a portion of heat of the exhaust gases before the flue gases enter the chimney and discharged to the atmosphere. Due to the high temperature of feed water, fuel consumption reduces. This increases the overall efficiency of the boiler.
10. What is the function of superheater in the boiler?
a) Increase the temperature of steam
b) Reheat the steam
c) Superheat the feed water
d) To heat the fuel gas
Answer: a
Explanation: Function of the superheater is to increase the temperature of steam above its saturation temperature. As heat contained in unit mass of superheated steam is more than dry saturated or wet steam, it is extensively used in steam power plants.
11. What is the function Air heater in the boiler?
a) Preheat the air before entering the boiler
b) Recover the heat from flue gas
c) Heating of economizer tubes
d) Reheat the gas coming out of economizer
Answer: b
Explanation: Function of air preheater is to recover the heat of a portion of exhaust flue gases before the flue gases enter the chimney. It is places along the passage of the exhaust flue gases in between the economizer and the chimney.
12. Tubular air preheater of a boiler is also called as _________
a) recuperative air preheater
b) elliptical air preheater
c) ovoid air preheater
d) squarish air preheater
Answer: a
Explanation: Tubular air preheater is also called as recuperative air preheater. This type of air preheater is composed of steel tubes through which hot flue gases flow. Air is made to circulate over these steel tubes and thus gains heat.
13. What does regenerative air preheater consists of?
a) Rotor
b) Skewers
c) Propeller
d) Piston
Answer: a
Explanation: This type of air preheater consists of a rotor which turns about 2 to 3rpm. The rotor is filled with thin corrugated metal elements. Hot gases pass through one half of the heater and air through the other half. As the rotor turns, the heat storage elements transfer the heat absorbed from the hot gases to the incoming air.
14. What is the function of the feed water pump of a boiler?
a) Pump water at high pressure
b) To pump water at lower pressure
c) To pull back the water from boiler
d) To convert steam into water after the boiler process
Answer: a
Explanation: Function of feed water pump is to pump water at high pressure to the water space of the boiler drum. There are many types of feed pumps, in which they are mainly classified into rotary and reciprocating pumps.
15. Rotary pumps are driven by _________
a) electric motors
b) batteries
c) diesel engines
d) biogas fuel
Answer: a
Explanation: Rotary pumps are driven by electric motors. Water is pumped due to rotary action of the impeller. Rotary pumps are invented by Charles C Barnes. It is a positive displacement pump. The efficiency of these pumps depends on the percentage of slip to the total quantity displaced.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Boiler Mounting Accessories – 2”.
1. Which of the following is an example of reciprocating pump?
a) Lobe pump
b) Barrel pump
c) Vane pump
d) Hand pump
Answer: d
Explanation: Hand pump is the example of a reciprocating pump. Reciprocating pumps when made use inside a boiler. They are continuously run by steam from the same boiler to which the water is fed. Water is pumped by reciprocating action.
2. When is it difficult to maintain the pressure inside the boiler?
a) When steam demand is fluctuating
b) When steam demand is high
c) When steam demand is low
d) When steam demand is constant
Answer: a
Explanation: Whenever the steam demand is fluctuating, it becomes very difficult to maintain uniform pressure. In such of these cases pressure reducing valve is made utilized by connecting to steam supply line. Function of the pressure reducing valve is to maintain constant pressure on the delivery side of the valve with the fluctuating boiler pressure.
3. How many types of steam traps are generally used in the boiler?
a) 1
b) 2
c) 3
d) 4
Answer: b
Explanation: Two types of steam traps are generally used in the boiler. The function of steam trap is to drain off water resulting from the partial condensation of steam in the steam pipe lines and jackets without allowing the steam to escape through it.
4. Where is steam separator installed in the boiler?
a) Close to the engine
b) Close to the economizer
c) Close air preheater
d) Near to the superheater
Answer: a
Explanation: Function of the steam separator is to separate the water particles in suspension that are carried by the steam coming from the boiler. It is always installed as close to the engine or turbine as possible on the main pipeline.
5. Which materials are used for Super heater tubes?
a) Nickel chromium
b) Alnico
c) Chromium Molybdenum
d) Magnox
Answer: c
Explanation: Superheater is made of coils of tubes forming parallel tube circuits connected between heaters. The superheater tubes are made of high temperature strengths special alloy steels such of chromium molybdenum. The coils are heated by the heat of combustion gas during their passage from furnace to the chimney.
6. Super heaters are commonly classified into how many types?
a) 1
b) 2
c) 3
d) 4
Answer: b
Explanation: Super heaters are commonly classified into two types: Radiant superheater and convective superheater. If superheater absorbs heat from the burning fuel through radiation than it is known as Radiant Superheater. If the superheater that receives its heat entirely from the gases through convective heat transfer is called Convective superheater.
7. How many methods of superheater temperature control are there?
a) 5
b) 8
c) 4
d) 2
Answer: b
Explanation: There are eight methods of superheater temperature control. They are:
Bypassing the furnace
Tilting burners in the furnace
Auxiliary burners
De-superheater using water supply
Pre condensing control
Gas circulation
Twin furnace arrangement
Coil immersion in boiler drum.
8. In the method of ‘Tilting burners in the furnace’ at what degree are the burners tilted?
a) 10 o
b) 15 o
c) 30 o
d) 45 o
Answer: c
Explanation: In this following method of a superheater temperature control burners in the furnace are tilted up or down through a range of 30 o . When burners are tilted downwards much of heat is given to the water walls by the gas and the gas entering the super heater region is relatively cool.
9. What is the function of Re-heater in the boiler?
a) To get excess amount of heat
b) To make utilize of the left over water in the tubes
c) Re-super heat partly expanded steam
d) Better heating efficiency in winters
Answer: c
Explanation: The function of Re-heater is to re-superheat the partly expanded steam from the turbine so that the steam remains dry as far as possible through the last stage of turbine. Modern plants have reheaters as well as super heaters in the same gas passage of the boiler.
10. How many types of economizers are there?
a) 6
b) 8
c) 5
d) 3
Answer: a
Explanation: There are six types of economizers:
i) Steaming
ii) Independent
iii) Non-steaming
iv) Integral
v) Condensing
vi) Non-condensing.
11. Which is the most common type of economizer used in the thermal plants?
a) Steaming
b) Integral
c) Independent
d) Non-Condensing
Answer: d
Explanation: The most common type of economizer used in thermal power plant is the Non-condensing thermal power plant. They are Heat exchanger tubes with fins around the in the form of spiral and they are located inside the duct at the exit region of the boiler.
12. Which type of economizer is used in Natural gas fired thermal plant?
a) Condensing
b) Steaming
c) Integral
d) Independent
Answer: a
Explanation: Condensing economizers are used in natural gas fired thermal power plant. They reduced the flue gas temperature below condensation temperature as low as 25 o C. They increase the boiler efficiency by 10-15%. While using the condenser the fuel should not contain sulfur.
13. Select the benefit of preheating the air?
a) Increased thermal efficiency
b) Improved oxidation
c) Controlled steam capacity
d) Decreased power consumption
Answer: a
Explanation: Increased thermal efficiency is one of the benefits and also other benefits are
i) Improved combustion
ii) Efficient use of low grade fuel
iii) Saving in fuel consumption
iv) Increased steam generation capacity.
14. Which type of air heater consists of a bunch of hollow leaves of sheet metal?
a) Plate air heater
b) Tubular air preheater
c) Regenerative
d) Integral
Answer: a
Explanation: The plate type air heater consist a bunch of hollow leaves of sheet metal electrically welded and assembled in housing. The spacing between the adjustment leaves and the width of the opening of leaves are such that air and gas passages are of different widths.
15. Which type of air preheater is often preferred at thermal stations?
a) Regenerative heater
b) Tubular air heater
c) Plate air heater
d) Integral heater
Answer: a
Explanation: In the regenerative heater same surface is alternately heated and cooled by the air and gas steams through respective operating cycles. These are often preferred in thermal station due to its compactness, accessibility and reduced weight.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Components of a Diesel Engine Plants”.
1. What is the range of power that diesel engine plants produce?
a) 1 to 50MW
b) 50 to 100MW
c) 40 to 80MW
d) 200 to 300MW
Answer: a
Explanation: Since the invention of diesel engine, diesel engine plants are finding increased application as either continuous or peak load source of power generation. Due to economy of operation DG plants are used to generate power in the range of 1 to 50MW capacity.
2. Diesel engine plants are not more efficient than any other heat engines of comparable size.
a) True
b) False
Answer: b
Explanation: DG plants are more efficient than any other heat engine of comparable size. It is available at very short delivery times and can be started quickly and brought into service. It can burn fairly wide range of fuels.
3. What is the use of Air filter in the Diesel engine plant?
a) Air filter cools down the air
b) Air filter changes direction of air flow
c) Air filter removes dust from air
d) Air filter helps in flow of fuel
Answer: c
Explanation: Air filter removes the dust from air before entering the engine. Air actually contains oxygen which supports the combustion inside the engine chamber. And also helps in moving/taking out the exhaust fumes which are produced after combustion.
4. What is the necessity of supercharger in the diesel engine plants?
a) Supercharger helps in drawing out heat from engine
b) Supercharger supports engine as auxiliary source of power
c) Supercharger improves engine efficiency
d) Supercharger increases pressure of air
Answer: d
Explanation: Supercharger increases the pressure of air at engine inlet and hence increases engine power. They are usually driven by the engines. It usually situated after the air filter. The power for supercharger can be provided by mechanical means of belt, gear, shaft or chain connected to engine’s crankshaft.
5. What is requirement of cooling system in diesel plants?
a) Eliminate hotness of air entering into the filter
b) To act as a filter for main fuel tank
c) Eliminate heat coming out of engine
d) To cool down lubrication system
Answer: c
Explanation: The system includes water circulating pumps, cooling towers are spraying ponds and water filtration or treatment plant. The purpose of cooling system is to ensure the life of cylinder by extracting the heat developed from the engine cylinder walls and hence keeping the temperature within the safer range.
6. What is the need for lubrication system in the Diesel engine plant?
a) To act a coolant in the diesel engine plant
b) To act as emulsifying agent for the fuel
c) To eliminate friction between the mating parts
d) To improve the efficiency of the fuel used
Answer: c
Explanation: The system includes oil pumps, oil tanks coolers and connecting pipes. The system reduces the friction between the moving parts and hence reduces wear and tear. Lubricating oil also controls the temperature at mating point.
7. How is governing of fuel done?
a) By varying fuel supply
b) By pressure of fuel supply
c) By adding emulsifying agents
d) By sprinkling the fuel
Answer: a
Explanation: The governing engine maintains constant speed of the engine irrespective of the load on plant. This is done by varying the fuel supplied to the engine. It could be very be really impractical and dangerous to run an engine without the governor or speed control mechanism and could lead to accidents such as collision or grounding.
8. Small service storage tanks in a fuel system of diesel plant are known as ________
a) temporary fuel tank
b) engine day tank
c) reserve
d) main fuel tank
Answer: b
Explanation: The fuel oil may be delivered at the plant side by trucks, railroad tank cars or barge and tankers. From tank truck the delivery is done using the unloading facility to main storage tanks. This fuel is then transferred by pumps to small service storage tanks know as engine day tanks.
9. How amount of storage of fuel is done?
a) A week’s requirement
b) For 4 day requirement
c) For a Month’s requirement
d) For annual requirement
Answer: c
Explanation: The minimum storage capacity of at least a month’s requirement of fuel is generally kept in bulk. However, when the advantage of seasonal fluctuations in cost of oil is to be availed, it may be necessary to provide storage for a few months requirement.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Fuel System”.
1. Which among the following are of great importance in a diesel power plant?
a) Tight pipe joints
b) Orifices
c) Air compressors
d) High grade filters
Answer: d
Explanation: Due importance should be given for cleanliness in handling bulk fuel oil. Dirt particles will ruin lap of injection pumps or plug the injection nozzle orifices. Thus, high grade filters are of great importance to the diesel oil supply system.
2. Fuel injection system is the _______ of the diesel engine.
a) sole part
b) heart
c) main part
d) part
Answer: b
Explanation: Function of fuel injection system are:
Filter the fuel.
Measure the correct quantity of fuel to be injected.
Proper time the fuel injection.
Control the rate of fuel injection.
Break up the fuel into fine particles.
Properly distribute the fuel in the combustion chamber.
3. How much amount of fuel must be measured out in a fuel injection system?
a) Very high
b) Very Small
c) High
d) Medium
Answer: b
Explanation: Fuel injection system is the heart of diesel engine. In an injection system very small quantity of fuel must be measured out, injected, atomized, and mixed with combustion air. The mixing problem becomes more difficult. The larger the cylinder and faster is the rotational speed. However, special combustion arrangements such as pre-combustion chambers, air cells etc, are necessary to ensure good mixture.
4. Injection systems are cheap.
a) True
b) False
Answer: b
Explanation: The injection systems, especially the parts that actually are manufactured with great accuracy meter and inject the fuel. Some of the tolerances between the moving parts are so small that they require some special attention during manufacture. Hence the injection systems are costly.
5. How many are the number of commonly used fuel injection systems in diesel power stations?
a) 2
b) 4
c) 3
d) 5
Answer: c
Explanation: There are three most commonly used fuel injection systems in diesel power station, they are:
i) Common rail injection system.
ii) Individual pump injection system.
iii) Distributor.
6. Atomization of fuel can be done in how many ways?
a) 2
b) 3
c) 4
d) 5
Answer: a
Explanation: Atomization of fuel can be done by Air blast Pressure spray. In the olden days engines used air fuel injection at about 70bar which is sufficient not only to inject the oil, but also to atomize it for rapid and thorough combustion. The expense of providing an air compressor tank leads to the development of “solid” injection.
7. How many types of common rail injection systems are there?
a) 1
b) 2
c) 3
d) 4
Answer: b
Explanation: There are basically two types of common rail injection systems which are by using single pump and using controlled pressure system. In case of single pump, it supplies high pressure fuel to header. In the controlled pressure system, it has a pump which maintains a set head pressure.
8. Common rail system prototype was first developed in year?
a) 1945
b) 1950
c) 1960
d) 1975
Answer: c
Explanation: The common rail system prototype was developed in late 1960s by Robert Huber of Switzerland and the technology further developed by Dr. Marco Ganser at the Swiss federal institute of technology in Zurich, later of Ganser-Hydromag AG Oberageri.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Engine Starting Methods – 1”.
1. The automotive battery is also known as __________
a) lithium ion battery
b) lead-acid storage battery
c) zinc carbon battery
d) weston cell battery
Answer: b
Explanation: The automotive battery, also known as Lead-acid storage battery is an electrochemical device that produced voltage and delivers current. In an automotive battery we can reserve the electrochemical action, thereby recharging the battery, which will then give many years of service.
2. What is present inside a battery?
a) Electrolyte
b) Fluids
c) Acid
d) Steam
Answer: a
Explanation: The electrolyte inside the battery is a mixture of sulfuric acid and water. Sulfuric acid is very corrosive; if it gets on your skin it should be flushed with water. The automotive battery requires special handling. If it gets in your eyes it should be flushed with mild solution of baking soda and water.
3. What do batteries emit while charging?
a) Nitrogen
b) Oxygen
c) Hydrogen
d) Carbon
Answer: c
Explanation: When charging, the battery will emit hydrogen gas; it is therefore extremely important to keep the flames and sparks away from battery. It is also advisable to wear goggles and gloves while servicing the battery.
4. The battery cannot be sealed because ____________
a) they emit noxious gases
b) they emit hydrogen
c) to be exposed to air
d) to have the ventilation
Answer: c
Explanation: Because batteries emit hydrogen gas while charging, the battery case cannot be completely sealed. Years ago there was a vent cap for each cell and we had to replenish the cells when the electrolyte evaporated. Today’s batteries have small vents on the side of the battery; the gases emitted have to go through baffles to escape.
5. What does CCA stand for in engine starting methods?
a) Circuit card assembly
b) Cold cranking amps
c) Chromated copper arsenate
d) Capital cost allowances
Answer: b
Explanation: Today’s batteries are rated in term of cold cranking amps. This represents the current that the battery can produce for 30 seconds at 0 o C before the battery voltage drops below 7.2 volts. An average battery today will have a CCA of 500.
6. Which of the following problem naturally occurs around the battery?
a) Corrosion
b) Scaling
c) Pore formation
d) Rust
Answer: a
Explanation: Corrosion naturally occurs around the battery. Electrolyte condensation contains corrosive sulfuric acid, which destroys the metal of battery terminals, cable ends and battery hold down parts. To clean away the corrosion, use a mixture of baking soda and water.
7. How many key switch positions are there in general in ignition switch?
a) 2
b) 3
c) 4
d) 5
Answer: d
Explanation: The ignition switch allows the driver to distribute electrical current to where it is needed. There are generally 5 key switch positions they are:
i) Lock
ii) Off
iii) Run
iv) Start
v) Accessory.
8. In which switch position are all circuits open?
a) Lock
b) Run
c) Start
d) Accessory
Answer: a
Explanation: In lock position all circuits are open and the steering wheel is in lock position. In some cars, the transmission lever cannot be moved in this position. If the steering wheel is applying pressure to the locking mechanism, the key might be hard to turn.
9. In which ignition switch position is the power supplied to ignition circuit?
a) Off switch position
b) Run switch position
c) Start switch position
d) Lock switch position
Answer: c
Explanation: Power is supplied to the ignition circuit in start switch position. That is why the media stops playing in the start position. This position of the ignition switch is spring loaded so that the starter is not engaged while the engine is on. This position is used momentarily, just in order to activate the starter.
10. Neutral safety switch varies due to changes in ________
a) ignition
b) applying clutch
c) gear transmission
d) brakes
Answer: c
Explanation: This switch opens the starter circuit when the transmission is in any gear but Neutral on automatic transmissions. This switch is normally connected to the transmission linkage or directly on the transmission. Most cars utilize this same switch to apply current to the backup lights when the transmission gear is put in reverse.
This set of Energy Engineering online test focuses on “Engine Starting Methods – 2”.
1. What is a relay?
a) A device that resists the flow of Current
b) A device that resists the flow of direction in two ways
c) Device that allows small electrical current to control large electrical current
d) A device that allows the operator to control the current flow in the required direction
Answer: c
Explanation: A relay is a device that allows a small amount of electrical current to control a large amount of current. An automobile starter uses a large amount of current to start an engine. If we allow much current to go through the ignition switch, we would need a very large switch.
2. Years ago diesel engines were started with small engines called ________
a) mini engines
b) runty engines
c) pup engines
d) puny engines
Answer: c
Explanation: Years ago diesel engines were started with the small engines called pup engines. And another way used to start a diesel engine was by gasoline and switch it over to diesel fuel. A 12v electrical system became very popular and later on they were used.
3. How is minimum cranking speed achieved?
a) By providing the hp
b) By providing speed
c) By providing torque
d) By proving sufficient amount of fuel
Answer: c
Explanation: Minimum cranking speed is achieved by providing the necessary torque, which is actually a purpose of starter motor. As the starter motor rotates the flywheel, the crankshaft is turned, which then starts piston movement.
4. Engine cranking is difficult in which temperatures?
a) Moderate
b) Hot
c) Humid
d) Cold
Answer: d
Explanation: The engine cranking is difficult in colder temperatures especially if engine is directly driving other machine equipments such as torque converter or hydraulic pumps. Cold engine oil adds to the load on starter, and this load may increase by 3 to 4 times what it would normally be in warmer weather.
5. Which is the recent difficulty added to the starting systems?
a) Fuel flow
b) Gear transmissions
c) Electronic controls
d) Fuel consumption
Answer: c
Explanation: The recent difficulty added to the stating system is electronic controls in engines. Some electronic control machines may need some minimum number of revolutions at a minimum speed before energizing the fuel system.
6. If the starter is used properly, for how many starts will it last?
a) About 8000
b) Over 10000
c) Upto 40000
d) At least 25000
Answer: b
Explanation: If the starter is used properly, it will last for over 10000 starts. The biggest factor affecting the life of a electric starter is overheating and over-cranking. Never run the starter switch for more than 30 seconds continuously.
7. What is CRDi?
a) Common rail direct infusion
b) Common rail direct injection
c) Common rail diesel injection
d) Common rail diesel infusion
Answer: b
Explanation: CRDi id common rail direct injection, which says direct injection of fuel into cylinders via a common single rail called single line which is connected to all the fuel injectors. This system is commonly equipped in diesel engines.
8. What is CDI?
a) Common diesel injection
b) Common direct injection
c) Capacitor discharge ignition
d) Capacitor direct ignition
Answer: c
Explanation: CDI stands for capacitor discharge ignition or thyristor ignition is a type of automotive electronic ignition system which is widely used in the outboard motors, motorcycles, chainsaws, lawn mowers and some cars.
9. What does TDI stand for?
a) Turbocharged diesel injection
b) Turbocharged direct injection
c) Turbocharged discharged infusion
d) Turbocharged Direction ignition
Answer: b
Explanation: TDI stands for Turbocharged direct injection is a design of turbo diesel engines. These are used in vehicles, also used in the marine engines. In this fuel injector sprays atomized fuel into main combustion chamber of each cylinder.
10. What is GDI engine?
a) Gasoline direct injection
b) Gasoline diesel injection
c) Gasoline discharge injection
d) Gasoline direct infusion
Answer: a
Explanation: In non-diesel IC engines, GDI , also known as petrol direct injection, Fuel satisfied ignition etc. Emission levels can be easily and accurately controlled with diesel systems.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Lubrication System, Intake and Exhaust Systems”.
1. Why does a large diesel engine plant require air?
a) To support combustion
b) To remove dust particles
c) To blow out fumes
d) To run the engine
Answer: a
Explanation: A large diesel engine plant requires about 0.076 m 3 /min to 0.11m 3 /min of air per KW of power developed inside the engine. Air contains lot of dust; hence it is necessary to remove the dust content in the atmospheric air.
2. What happens if atmospheric temperature is too low?
a) Engine misfires at low loads
b) Engine consumes more amount of fuel
c) Engine gets struck up
d) Exhaust produced comparatively more
Answer: a
Explanation: The air system contains an intake manifold located outside the building with filter to catch dirt which would otherwise cause excessive wear in the engine. If the atmospheric temperature is too low, engine misfires at low loads and hence it is necessary to install a heating element using exhaust gas.
3. What is used in engines to reduce the noise at the exhaust?
a) Noise dampers
b) Baffles
c) Silencers
d) Composite foam
Answer: c
Explanation: Engine sound during operation may be transmitted back through the air intake systems to the outside air. In such cases a silencer is provided between the engine and the intake. It is a light weight steel pipe.
4. In which type of dust filter used in engine is the air swept over or through the pool of oil??
a) Oil bath type
b) Dry-type
c) Soot blower
d) Bessel filter
Answer: a
Explanation: in oil bath type of filter the air is swept over or through a pool of oil. The dust particles become coated to the oil. The air is then passed through the filter, which retains the oil coated dust particles.
5. Which type of filter used in engine is made up of cloth, felt and glass wool?
a) Dry-type
b) Oil-bath type
c) Soot blower
d) Bessel filter
Answer: a
Explanation: Dry type of filter is made up of cloth, felt and glass wool etc. the filters catch dirt by causing it to cling to the surface of filter material. The capacity of such filters drops progressively when they are in use. The cleaning is done by amount of air used by the engines and dust concentrate in it.
6. What is muffling?
a) Reducing vibration
b) Increasing the flow of gas
c) Reducing noise
d) Filtering the exhaust air
Answer: c
Explanation: Muffling is the process of reducing the noise. The exhaust system must carry approximately 0.23m 3 /min-0.30m 3 /min of gases per kilowatt developed, at the average exhaust temperature. Muffling of the exhaust noise is done by using silencers located outside building.
7. Exhaust pipe is designed carefully in order to carry toxic gases away from the user machine.
a) True
b) False
Answer: a
Explanation: An exhaust pipe must be carefully designed to carry toxic and noxious gases away from the users of the machine. It is done so because the gases produced may affect the human being in health wise as well as the environment.
8. Why is lubrication system important in the engine?
a) To improve fuel efficiency
b) To provide cooling
c) To reduce the disturbance
d) To help move the fuel easily
Answer: c
Explanation: Due to the presence of friction, wear and tear of the engine parts takes place reducing the engine life. The lubricant introduced forms a thin film between the rubbing surfaces and prevents metal to metal contact.
9. In which type of lubrication method are splash rods used?
a) Full pressure lubrication
b) Mechanical lubrication
c) Force feed lubrication
d) Spray lubrication
Answer: a
Explanation: In full pressure lubrication splash rods equipped. An oil pump supplies lubricating oil to many parts of the engine through duct system and to the crank shaft through drilled holes. The cylinder walls are lubricated by oil mist that is slung outward by the splash rod connected to flywheel from pool of oil.
10. Why is oil cleaning is necessary in the engine?
a) For continuous reliable operation
b) To cool down the oil
c) To reduce the viscosity of oil
d) To increase thickness of oil
Answer: a
Explanation: For continuous reliable operation attention should be given to oil cleaning. For this purpose filters with centrifuges or chemical action have been employed. Mechanical filters include cloth bags, wool, felt pads, paper discs and cartridge of porous material.
11. Rough cleaning of oil in engine is done through passing the oil through?
a) Paper discs
b) Nozzle
c) Felt pads
d) High speed centrifuges
Answer: d
Explanation: Rough cleaning of oil is done by passing oil through high speed centrifuges. Centrifuges can be done by periodic centrifuging of the entire lubricating oil or by continuous cleaning of a small fraction of it by splitting the oil from main flow and returning back to main stream.
12. Oil is cooled before passing it to the engine.
a) True
b) False
Answer: a
Explanation: Oil should be heated before passing it through the centrifuge and then it is cooled before supplying it to the engine. As heat is developed due to friction between the moving parts, the cooling is done by using water from the cooling tower.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Hydrology – 1”.
1. How does Hydro power plays important in development of a country?
a) Shows the amount of water power in a country
b) Providing abundant amount of power
c) Providing power at cheap rate
d) Power production by hydro power plant is easier
Answer: c
Explanation: In the development of a country the hydro power plays a very important role because it provides power at cheapest rates. No raw material is required for the production of power from hydro power plant.
2. How much of the total amount of power developed world wide consists of hydro power plant?
a) 10%
b) 20%
c) 30%
d) 40%
Answer: b
Explanation: Nearly 20% of the total world’s power is generated using hydro power plants. To countries in the world 90% of the nation’s power requirement is met by hydro power. When compared country wise this amount is very high.
3. Which two countries have vast hydro resources?
a) Hungary and Luxemburg
b) India and china
c) Russia and Nepal
d) Japan and Georgia
Answer: c
Explanation: Russia and Nepal have vast hydro resources that are to be harnessed. As per the estimation of world power organization, the world hydro potential is roughly 5000GW whereas only 4% of it is presently developed.
4. What type of energy does rain falling holds relative to the oceans?
a) Potential energy
b) Kinematic energy
c) Electrical energy
d) Motion energy
Answer: a
Explanation: Rain falling on earth surface has potential energy relative to oceans towards which it flows. This energy can be converted into shaft work by hydraulic prime mover and finally into electrical energy. The conversion of this energy takes time.
5. The shaft power developed by the water passing through the prime mover is given by _______
a) P = \(\frac{mgH}{1000}\) × n o .
b) P = \(\frac{mgH}{10}\) × n o .
c) P = \(\frac{mgH}{100}\) × n o .
d) P = \(\frac{mgH}{n_{o^.}}\) × 1000
Answer: a
Explanation: energy-engineering-questions-answers-hydrology-1-q5a
Where, m = Rate of water flow in kg/sec.
H = Height of fall in meters.
n o = overall efficiency.
6. On what does generation of Hydro power depends?
a) Quantity of water available
b) On capacity of turbine
c) Height of head
d) Storage capacity
Answer: a
Explanation: Generation of power depends on the quantity of water available. The available head depends upon the selection of site for hydraulic power plant. The site of the power plant is always selected for the highest available head when other things are in favor of site selection.
7. On what does the Quantity of water available at selected site depends?
a) Temperature at the selected site
b) Humidity at selected site
c) Vegetation of the area
d) Hydrological cycle of area
Answer: d
Explanation: The quantity of water available at the selected site depends upon the hydrological cycle of nature. The quantity of water available can be determined from the study of rainfall and run off in the area.
8. Capacity of hydraulic plant is dependent on __________
a) Minimum quantity of water available
b) Vegetation of the selected area
c) Maximum quantity of water available
d) Available head
Answer: a
Explanation: As the availability of water depends on natural phenomenon of rain, the maximum capacity of hydraulic generating plant is usually fixed on the basis of minimum quantity of water available at selected site.
9. What are used to store water during peak periods?
a) Storage drums
b) Canals
c) Sews
d) Storage Reservoirs
Answer: d
Explanation: The capacity of the hydraulic plant is done on the basis of minimum quantity available. Usually storage reservoirs are constructed for such plants in order to store the water during peak periods of runoff and supply the same during off peak periods of runoff.
10. The evaporation of water from the surfaces and its precipitation is known as ___________
a) Science
b) Infiltration
c) Hydrological cycle
d) Vegetation
Answer: c
Explanation: It’s the science which deals with rainfall and runoff. The evaporation of the water from the surfaces of river and oceans and its precipitation on the earth is known as hydrological cycle. This happens in a particular amount of period.
This set of Energy Engineering online quiz focuses on “Hydrology – 2”.
1. On what aspect is precipitation calculated?
a) Based on hydrological aspect
b) Based on climatic conditions
c) Based on the vegetation of the area
d) Based on weather forecast
Answer: a
Explanation: The evaporation of the water from the surfaces of river and oceans and its precipitation on the earth is known as hydrological cycle. Based on hydrological aspect the distribution of precipitation on the earth surface and beneath the earth is calculated.
2. Water evaporated is carried with the air in form of vapor known as _______
a) Cloud
b) Drizzle
c) Fog
d) Smoke
Answer: a
Explanation: It is the science which deals with rainfall. Water is evaporated from plants, rivers, oceans and carried with the air in the form of vapor which is known as cloud. Clouds vary in different shape and size and they move according to winds.
3. When does vapor turn into form of water or snow?
a) Cooled below Dew point
b) At Frost point
c) When cooled Freezing point
d) When there is rise in Humidity
Answer: a
Explanation: Water is evaporated from surface of earth and stored in form of clouds. When the vapors in the atmosphere are cooled below dew point temperature, it falls in the form of water or snow depending on the atmospheric temperature.
4. What source of energy does evaporation and precipitation consists of?
a) Perennial energy
b) Gravitational energy
c) Thermal energy
d) Kinetic energy
Answer: a
Explanation: This evaporation and precipitation is a natural continuous process and therefore constitutes a perennial source of energy. Both these evaporation and precipitation come under the hydrological cycle.
5. Water on the ground surface entering the soil is called _________
a) Infiltration
b) Transpiration
c) Filtration
d) Precipitation
Answer: a
Explanation: Infiltration is the process by which water on the ground surface enters the soil. Infiltration rate in soil science is a measure of the rate at which soil is able to absorb rainfall. It is measured in inches per hour or millimeters per hour.
6. The energy input to the hydrological cycle is by ____________
a) Wind
b) Water
c) Sun
d) Head
Answer: c
Explanation: The energy input to hydrological cycle is sun. Due to sun, water evaporates from water bodies. On cooling, the vapors form cloud which falls down in the form of rain, snow, hail etc which is known as precipitation.
7. About how much amount of precipitate is returned back to atmosphere?
a) 2/3
b) 1/4
c) 3/4
d) 1/3
Answer: a
Explanation: Precipitation includes all water that falls from the atmosphere to earth’s surface in any form. About 2/3 portion of precipitation that reaches land surface is returned back to atmosphere by water surfaces, soil and vegetation.
8. Amount of rainfall which runs off the earth’s land surface to form stream is used for ______
a) Flower generation
b) Back water storage
c) Pit Irrigation
d) Left through canals
Answer: a
Explanation: About 2/3 portion of rain is returned back to atmosphere and 1/3 portion is returned back by oceans. The amount of rainfall which runs off the earth’s land surface to form streams and rivers is used for flower generation.
9. What is the unit of runoff ________
a) Day-sec meter
b) M 2 /s
c) MM/S 2
d) Ns/m 2
Answer: a
Explanation: The unit of runoff is m 3 /s or Day-second meter.
1 Day second meter = Discharge collected in catchment area at the rate of 1 m 3 /s or for one day => 1 x 24 x 3600 = 86400 M 3 /s
And Total run off is given by:
Total Run-off = Direct runoff over the land surface + Run-off through seepage.
10. Where is the catchment area situated with respect to dam?
a) Behind the dam
b) Front of dam
c) Right beneath the dam
d) Opposite to the Dam Head
Answer: a
Explanation: Catchment area of a hydro site is the total area located behind the dam, Draining water into the reservoir. The place is usually steep at this point. And the Dam head acts as outlet point to let out the water after utilizing it for power production.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Rainfall and its Measurement – 1”.
1. Rainfall is also known as ___________
a) Precipitation
b) Condensation
c) Infiltration
d) Down pour
Answer: a
Explanation: The rainfall is also known as precipitation, is a natural process of atmospheric vapor into water. Atmospheric vapor are nothing but clouds which are contamination of air and water. When the temperature goes below dew point then precipitation takes place.
2. In which of the following season is evaporation loss from free water is large?
a) Winter
b) Spring
c) Autumn
d) Summer
Answer: d
Explanation: During summer, the evaporation loss from free water surface is considerably large and this evaporated water finds room in the air mass. The water holding capacity of air in the form of vapor is also considerably large in hot weather.
3. Rate of rainfall is expressed in _____________
a) Centimeters
b) Millimeters
c) Meters
d) Kilometers
Answer: a
Explanation: The rate of rainfall is expressed in centimeters of water during a given period of time. One centimeter rainfall is the quantity of water collected on a certain area due to rainfall which becomes one centimeter in height.
4. Average annual rainfall ranging to dessert to hilly regions would be ________________
a) 1100cm
b) 2500cm
c) 845cm
d) 500cm
Answer: a
Explanation: The rainfall varies widely from one part of the world to another, ranging from desert regions to the hilly regions where the average annual rainfall may be over 1100cm. in some regions, the seasonal variation is very slight and monthly rainfalls are relatively uniform.
5. The annual rainfall at any given station varies from _________
a) month to month
b) weekly basis
c) year to Year
d) quarterly
Answer: c
Explanation: The annual rainfall at any given station varies irregularly from year to year. The range of this variation marks the reliability of the rainfall and has great importance in the design of storage reservoirs.
6. Intensity of rainfall is measured by___________
a) Continuously recording gauge
b) Anemometer
c) Hydrometer
d) Seismometer
Answer: a
Explanation: The intensity of rainfall is expressed as an amount of precipitation in a stead period. During heavy rainstorm the intensity of rainfall varies widely from minute to minute and can be measured only with a continuously recording gauge.
7. The relation between the area of rainstorm and its average intensity is used in assessing _________
a) Amount of water
b) Amount of rain
c) Amount of wind
d) Amount of duration of rain
Answer: b
Explanation: The relation between the area of rainstorm and its average intensity is used in assessing the amount of rain which may be expected to fall upon a catchment area within a given period. The intensity of rainfall is equally important in the design of spillways during heavy rain periods.
8. The intensity of rainfall is given by ______
a) I = R/
b) I = R/
c) I = /R
d) I = /C
Answer: a
Explanation: The intensity of rainfall is given by,
I = R/
Where, I = intensity in inches/hr.
T = Duration of rain storm in hours
R & C = these are constants quoted by different authorities for different areas of world.
The intensity also depends on the area selected for the measurement.
9. In what way are all the precipitations measured?
a) Vertical depth
b) Horizontal area
c) Width of area
d) At slope
Answer: a
Explanation: All forms of precipitation are measured on the basis of vertical depth of water which would accumulate on the level surface if all the precipitation remained where it fell. The rainfall is usually measured with rain gauges.
10. How many types of rain gauges are there?
a) 2
b) 3
c) 4
d) 5
Answer: a
Explanation: There are two types of rain gauges. They are Non-recording type and recording type. Non-recording type do not record the depth of rainfall but only collect the amount of rainfall and recording type records the depth of rainfall in mm or cm.
11. Movement and filtering of fluid from porous material is called as __________
a) Percolation
b) Infiltration
c) Transpiration
d) Precipitation
Answer: a
Explanation: Percolation refers to movement and filtering of fluid from porous material. Usually the water which falls on the ground is filtered into the earth surface and is stored under the surface of earth. And this water also improves the ground fertility.
12. Where are funnel and receiver in Non-recording type placed?
a) Inside a Metal case
b) On top of the equipment
c) Below the base of equipment
d) In between the metal case
Answer: a
Explanation: The non-recording gauge usually consists of a standard funnel discharging into a receiver large enough to hold the maximum possible day’s rainfall. The funnel and receiver are placed in a metal casing with suitable packing.
13. The base of the non-recording type rainfall is permanently fixed in the concrete block.
a) True
b) False
Answer: a
Explanation: The base of the gauge is permanently fixed into a concrete block at a site where rainfall is to be measured. The precaution is taken during fixing, to level perfectly. The gauge is fixed in the block in such a way that the top of the gauge will be 30 cm above the natural surface level.
14. Which gauge gives the permanent record of rainfall?
a) Recording gauge
b) Non-recoding gauge
c) Copper daily gauge
d) Plastic gauge
Answer: a
Explanation: These are rain gauges which can give a permanent, automatic rainfall record in the form of a pen mounted on a clock driven chart. From the chart intensity or rate of rainfall in cm per hour. The recording is done by an attached siphon.
15. The drum situated in recording type makes one rotation for how many hours?
a) 4 hours
b) 24 hours
c) 6 hours
d) 12 hours
Answer: b
Explanation: The rotating drum is kept rotating continuously with the help of electric motor. The drum makes generally one rotation during 24 hours. On the rotating drum the graph paper is placed throughout its rotation the recording is made.
This set of Energy Engineering Question Bank focuses on “Rainfall and its Measurement – 2”.
1. How many years of minimum rainfall is required to design hydroelectric projects?
a) 10
b) 20
c) 25
d) 35
Answer: d
Explanation: In the design of hydro-electric projects, the rainfall record of nearly 35 years is required. This period is accepted as giving a reasonably accurate assessment of mean annual rainfall. Many times, it is not possible to wait many years for rainfall data and in such cases, shorter periods are accepted by design engineers with reserve and allowance is made for possible error.
2. There is requirement for wind shelter to reduce wind effect at rain gauge area.
a) True
b) False
Answer: a
Explanation: A wind shelter should be provided to reduce the effect of wind. The gauge should be erected on a level ground. The distance of the gauge from every object should not be less than twice the height of the object above the gauge.
3. What is the primary intention of rain gauging in hydro electric plant?
a) To determine force of storm
b) To determine monthly rainfall
c) To determine annual rainfall
d) To determine monthly and annual rainfall
Answer: d
Explanation: The primary intention of the rain gauging in hydroelectric work is to determine the monthly and annual rainfalls over catchment area. When the rain-gauging stations are more than one for a particular basin, calculation of average rainfall depending upon the area of the basin is done.
4. How many methods are used to determine the average rainfall depending upon area of basin in rain gauging?
a) 2
b) 3
c) 4
d) 5
Answer: b
Explanation: When there are more basins, three of the following methods are used to determine the average of rainfall depending upon the area of basin. They are Arithmetic mean method, Thiesson method and iso-hyetol method.
5. In which of the following rain gauging methods are the values of rainfalls of all stations added?
a) Arithmetic mean method
b) Thiesson method
c) Iso-hyetol method
d) Recording type
Answer: a
Explanation: In arithmetic mean method, the values of rainfalls of all the stations are added and the sum is divided by the number of gauging stations. This can be represented in the mathematical term as:
h a = \(\frac{h1+h2…….hn}{n} = \frac{Ʃh}{n}\).
6. Which among the following method is very accurate of rain gauging?
a) Arithmetic mean method
b) Thiesson method
c) Iso-hyetol method
d) Recording type
Answer: b
Explanation: Thiesson method is very accurate compared to other methods and is generally used when the catchment area lies between 500 to 5000km square. Assume that there are stations in the given basin names=d as 1, 2, 3, 4, 5, 6, 7, and 8. It is very important to divide the total basin area in such a way that each located station in the basin represents that area in the true.
7. Thiesson method is better result than arithmetic mean method because _________
a) It is shorter time consuming
b) Gives better detail about records
c) It is highly accurate
d) Small procedure
Answer: c
Explanation: The mean rainfall of the basin in thiesson method is given by:
h a = \(\frac{h1A1 + h2A2 + h3A3 + h4A4 + h5A5 + h6A6 + h7A7 + h8A8}{A1+A2+A3+A4+A5+A6+A7+A8}\)
This method gives better result than arithmetic mean method because it is very accurate and each point on a perpendicular bisector of the line joining the two gauging stations will be equidistant from both the stations. If one moves slightly this or that side of the bisector, the position will distinctly fall in the domain of that station of which ones position is now near.
8. In which of the following rain gauging method is contour joining the points of equal rainfall is done?
a) Arithmetic mean method
b) Thiesson method
c) Iso-hyetol method
d) Recording type
Answer: c
Explanation: In iso-hyetol method, contour joining the points of equal rainfall in the given catchment area is done. Iso-hyetes have following properties:
i) Two different iso-hyetes do not cross each other.
ii) Each iso-hyete closes on itself.
iii) Iso-hyete of higher value indicates the higher rainfall.
9. Two successive Iso-hyetes in the basin drawing of catchment area are measured using _______
a) Planimeter
b) Manometer
c) Mass flow meter
d) Chronometer
Answer: a
Explanation: Generally interval of iso-hyete is one cm. after drawing the iso-hyetes; the area between two successive iso-hyetes is measured by using a Planimeter. The rest of the procedure of finding out the mean rainfall is similar to that described in the second method.
10. Iso-hyete method is commonly used for the basin area above 500sq.km.
a) True
b) False
Answer: a
Explanation: Iso-hyete method is commonly used for the basin above 500sq.km. The analysis of rainfall for power generation purposes is usually more concerned with dry years rather than wet years. For the assessment of storage requirements, it is often necessary to determine the driest period for which provision must be made.
11. Study of shape and features of earth surface is called __________
a) Vegetation
b) Geography
c) Anatomy
d) Topography
Answer: d
Explanation: The study of the shape and features of the surface of the earth is known as topology and it is a very important factor which is affecting the runoff and also the nature of catchment area depends on it.
12. Vegetation affects the runoff.
a) True
b) False
Answer: a
Explanation: The transpiration and interception losses depend on the nature and extent of vegetation including crops. Vegetation, particularly of forest, has considerable effect upon the runoff. It consumes a proportion of the rainfall, causes interception losses and provides physical obstruction for runoff.
13. Rocky area gives higher runoff than sandy area.
a) True
b) False
Answer: a
Explanation: The geology of catchment area is of fundamental importance in the consideration of runoff. Rocky area gives higher runoff than sandy area. Even the evaporation losses increase with the increase in temperature.
14. The runoff calculated from the rainfall data available for sufficiently long period by multiplying with a coefficient is known as _________
a) Runoff coefficient
b) Rainfall coefficient
c) Topographic coefficient
d) Geo coefficient
Answer: a
Explanation: The runoff calculated from the rainfall data available for sufficiently long period by multiplying with a coefficient is known as runoff coefficient. The value of runoff coefficient is decided by considering all the factors which affect runoff.
15. The maximum rate of flow through the river is calculated by _________
a) Energy curves of flow
b) Force of flow
c) Pressure of flow
d) Head of flow
Answer: a
Explanation: The maximum rate of flow through the river is calculated by energy curves. Flood marks are also used to get the maximum flow rate. The following curves include Dickens formula, Inglis formula and ryve’s formula.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Hydrographs – 1”.
1. What do you call a graph which is plotted for discharge versus time?
a) Snow Graph
b) Hydrograph
c) Rain graph
d) Fluid graph
Answer: b
Explanation: The graph showing discharge of flowing water with respect to time for a specific time is known as hydrograph. The time period for discharge hydrograph may be hour, day, week or month. The discharge may m¬¬3/sec or day per second meter.
2. Choose the correct sentence about information available from hydrograph among the following options?
a) The mean annual runoff or mean runoff each week of the year
b) Total volume at that instant, as the area under hydrograph indicates the force of water during the duration
c) Rate of flow at any particular time during the duration period
d) Mean runoff for each month
Answer: d
Explanation: Mean runoff for each month is available. As compared to all other option, they would be- i) The mean annual runoff or mean runoff each month of the year. ii) Total volume at that instant, as the area under hydrograph indicates the volume of water during the duration. iii) Rate of flow at any instant during the duration period.
3. What does hydrograph based on day gives?
a) Idea about flood period during the month
b) Idea of rainfall
c) Idea of draught during the year
d) Idea of scarcity of water in the upcoming year
Answer: a
Explanation: The hydrograph can be drawn taking day, month or year. The hydrograph on the basis of day gives an idea of the flood period during the month. The hydrograph on basis of month gives an idea about the dry period of the year.
4. What information does the year wise hydrograph gives?
a) Draught
b) Heavy rainfall
c) Rising cold
d) Water scarcity
Answer: a
Explanation: The hydrograph can be drawn taking Day, month or year as time axis. The hydrograph based on year wise data gives information concerning the lean or draught year. This is very essential for deciding the location and size of hydel power plant.
5. When is the Hydrograph called as a unit hydrograph?
a) When 1cm of runoff is resulted from a rain fall
b) When 3cm of runoff is resulted from rainfall
c) When 1mm of runoff is resulted from rainfall
d) When 3mm of runoff is resulted from rainfall
Answer: a
Explanation: If the rainfall distribution in the storms is similar with respect to time and area, the ordinate of each hydrograph will be proportional to volume of runoff. The unit hydrograph is a hydrograph with a volume of 1cm runoff resulting from a rainfall of specified duration and a real pattern.
6. Unit hydrograph was explained by Sherman in which year?
a) 1925
b) 1928
c) 1932
d) 1945
Answer: c
Explanation: This unit hydrograph principle was expressed by Sherman in 1932; he introduced the theory of unit hydrograph. He pointed out that all hydrographs have same time resulting from rainfalls of the given duration.
7. Hydrographs of similar rainfalls will be similar in shape.
a) True
b) False
Answer: a
Explanation: Hydrographs of various rainfalls will be similar in shape. The ordinates are proportional to the runoff volumes within a fixed duration and similar rate and a real distribution of rainfall. However, the occurrence of identical rainfall is very rare.
8. What is unit hydrograph helpful in?
a) Estimating runoff from a basin
b) Estimating no of days of rain fall
c) Knowing the draught months in a year
d) In deciding the land for hydel power plant
Answer: a
Explanation: Unit hydrograph is helpful in estimating runoff from a basin for a storm of given duration. It is also helpful in predicting the expected flood flow from a catchment if rainfall intensity in the catchment is known.
9. What is the theoretical number of unit hydrographs for given basin?
a) 500
b) 2900
c) 36000
d) infinite
Answer: d
Explanation: The number of unit hydrographs for a given basin is theoretically infinite. This is because there may be one unit hydrograph for possible duration of rainfall and every possible distribution pattern of rainfall in the basin.
10. Above which range should be the unit hydrographs be used?
a) Around 5000 sq km
b) Over 2500 sq km
c) Around 4000 sq km
d) Below 5000 sq km
Answer: a
Explanation: In practice, only a limited number of unit hydrographs are used for a given basin. It is also common practice to neglect the variations in rainfall distribution within the basin area. Hence it is not advisable to use unit hydrograph method for basins over 5000 sq km.
11. The unit hydrographs can be successfully applied to basin areas of what sq km?
a) 15000 sq km
b) 10000 sq km
c) 3000 sq km
d) 25000 sq km
Answer: d
Explanation: The unit hydrographs can be applied successfully to basin areas as large as 25000 sq km. provided distribution patterns are classified into different types and unit hydrographs are developed for each type it is always preferable to divide the large basin into sub-areas, utilize hydrographs for each sub area independently and combine the resulting hydrographs together.
12. The magnitude of runoff as ordinates against the corresponding percentage of time as abscissa gives ________
a) Mass duration curve
b) Load duration curve
c) Power duration curve
d) Flow duration curve
Answer: d
Explanation: The magnitude of runoff as ordinates against the corresponding percentage of time as abscissa gives Flow duration curve. If the magnitude on the ordinate is the potential power contained in the stream flow, then the curve is known as power duration curve.
13. What is DWF?
a) Deep water flow
b) Dry weather flow
c) Drawing web format
d) Dam water flood
Answer: b
Explanation: Dry weather flow is a waste water flow in a sewer system during dry weathers with minimum filtration process while entering the ground. Insufficient flow velocities during DWF can increase retention.
14. What does CN stands for in hydrology?
a) Cyanide
b) Channel number
c) Cumulonimbus
d) Carbon nano-tube
Answer: c
Explanation: Cumulonimbus, from the Latin cumulus and nimbus, is a dense, towering vertical cloud associated with thunderstorms and atmospheric instability, forming from water vapor carried by powerful upward air currents.
15. What does ADF stand for in hydrology?
a) Automatic direction finder
b) Average daily flow
c) Average duration flow
d) Annual dry flow
Answer: b
Explanation: The daily effluent flow is required to calculate the area of septic field or the length of trench requires. It is also referred as the amount of water let out of a reservoir on the daily basis as per the requirement and demand.
This set of Energy Engineering Questions and Answers for Entrance exams focuses on “Hydrographs – 2”.
1. Cusec is___________
a) A unit of flow equal to one cubic feet per sec
b) A unit of flow equal to one centimeter cube per sec
c) A unit of flow equal to one meter per sec
d) A unit of flow equal to one cubic foot per sec
Answer: a
Explanation: Cusec is a unit of flow especially water which is equal to one cubic feet per sec. And there is also use of Cumec which is one cubic meter per second. One cubic feet per second is equal to 28.317 liters per second.
2. Find the power available if overall efficiency of plant is 80%, flow rate is 4.42cumecs and head 400m?
a) 6.52MW
b) 8.18MW
c) 11.255MW
d) 13.875MW
Answer: d
Explanation: Power available:
P = wQHn o X 10 -3 KW
= 9810 X 4.42 X 400 X 0.8 X 10 -6 MW
P = 13.875MW.
3. What would be the pondage factor for if hydropower plant is used for 10 hours?
a) P.F = 2.4
b) P.F = 1.2
c) P.F = 20
d) P.F = 0.4166
Answer: a
Explanation: Pondage factor = T1/T2 = /
P.F = 24/10 = 2.4.
4. Determine the capacity of hydro power plant to be used 10 hours peaking plant assuming daily flow in a river to be constant at 20m 3 /s. and overall efficiency is 80%?
a) 1.8835 MW
b) 5.5 MW
c) 3.25 MW
d) 1.0 MW
Answer: a
Explanation: Capacity of plant:
P = wQHn o X 10 -3 KW
P = 9810 X 20 X 12 X 0.80 X 10 -6
= 1.8835 MW.
5. Determine the flow rate of water, if the catchment area of hydroelectric power is 2500 km 2 , with an average rainfall of 160cm. the percolation and evaporation losses account for 19%?
a) 9639.8 M 3 /s
b) 42.8 M 3 /s
c) 859.63 M 3 /s
d) 2342 M 3 /s
Answer: a
Explanation: Amount of water available for power generation,
Q a = A X H X
= 2500 X 10 6 X 160/100
= 3.04 X 10 11 m 3
Flow rate of water,
Q = Q a /
= (3.04 X 10 -6 )/ = 9639.8 M 3 /s.
6. Determine the power developed, IF given data is H = 150m, n g = 0.91, n t = 0.86 and Q is 9639.8?
a) 74MW
b) 75MW
c) 76MW
d) 78MW
Answer: a
Explanation: Power developed = wQHn o X 10 -3 KW
= 9810 X 9639.8 X 0.86 X 0.91 X 10 -6 MW
= 74 MW.
7. Determine the pondage factor if the plant is working at peak time of 16 hrs?
a) 1.5
b) 0.75
c) 2.5
d) 0.3
Answer: a
Explanation: Pondage factor = T1/T2 = /
P.F = 24/16 = 1.5.
8. Find out the total flow volume in day sec meter for the average daily stream flow for 7 days?
Days Mean daily flow
1 100
2 300
3 200
4 120
5 50
6 30
7 20
a) 820 day sec meter
b) 95 day sec meter
c) 200 day sec meter
d) 524 day sec meter
Answer: a
Explanation: Total flow volume for 7 days:
= 24 X 3600 X
= 70848 X 10 3 m 3
= 70.848 million m 3
= 70848 X 10 3 /86400
= 820 day sec meter.
9. Determine the pondage factor if the plant is working at time of 8 hrs?
a) 2.5
b) 3.8
c) 1
d) 3
Answer: d
Explanation: Pondage factor = T1/T2
= /
P.F = 24/8 = 3.
10. What AEP stand for in hydrology?
a) Annual exceedance probability
b) Annual energy production
c) Annual exceedance period
d) Automatic engagement panel
Answer: a
Explanation: Annual exceedance probability refers to the probability of a flood event occurring in any year. The probability is expressed as a percentage. The probability that a given rainfall total accumulated over a given duration will be exceeded in any one year.
11. What is the volume of rainfall in day sec-meters if 6.5cm rainfall occurs over an area of 2400 sq.km?
a) 1805.56 day sec meter
b) 1225 day sec meter
c) 895 day sec meter
d) 1555.22 day sec meter
Answer: a
Explanation: Total rainfall
energy-engineering-questions-answers-hydrographs-2-q11
12. A lake behind a dam has a capacity of 30000km 2 -m approximately. For how many days would this water supply be sufficient to a city of 10 6 populations if daily requirement per person is 500 liters?
a) 60,000 days
b) 950 days
c) 25000 days
d) 8000 days
Answer: a
Explanation: Per day requirement: 500 X 10 3 liter = 500 X 10 3 m 3
Available water in the dam = 30000 X 10 6 m 3
No of days water supplied = 30000 X 10 6 /500 X 10 3 = 60000 days.
13. Determine the capacity of hydro power plant to be used 8 hours peaking plant assuming daily flow in a river to be constant at 65m 3 /s. and overall efficiency is 80% and head 12m?
a) 6.1214 MW
b) 5.5 MW
c) 31.25 MW
d) 22.0 MW
Answer: a
Explanation: Capacity of plant:
P = wQHn o X 10 -3 KW
P = 9810 X 65 X 12 X 0.80 X 10 -6
= 6.1214MW.
14. A hydel plant is supplied from a reservoir of 5 X 10 6 m 3 capacity at a head of 75m. Determine the number of electrical units produced during the year if the load factor is 0.6 and overall efficiency of generation is 72%?
a) 441.45MWh
b) 300.22MWh
c) 235MWh
d) 182MWh
Answer: a
Explanation: The power capacity of plant in KW is given as
P = mgH/1000 X n{overall}
= /
= 83.99Kw
Energy produced in kWh = P X Load factor X
= 83.99 X 0.6 X 365 X 24
= 4441451.44kwh
= 441.45 Mwh.
15. The graph of the cumulative values of water quantity against time is known as __________
a) Flow curve
b) Power curve
c) Mass curve
d) Load curve
Answer: c
Explanation: The graph of the cumulative values of water quantity against time is known as mass curve. A mass curve of the hydrograph which expresses the area under the hydrograph from one time to another.
This set of Energy Engineering Questions and Answers for Campus interviews focuses on “Site Selection for Hydro Electric Power Plants”.
1. Water gets polluted by submerged vegetation mineral.
a) True
b) False
Answer: a
Explanation: Water gets polluted by submerged vegetation mineral deposits, presence of algae, Leaves, twigs, logs under water decay and generates bad smelling gases. Thermal stratification and depletion of oxygen in lower strata generate harmful gases such CO 2 which pollute the water.
2. Water containing H 2 S, CO 2 and CH 2 are less corrosive to dam structure.
a) True
b) False
Answer: b
Explanation: Water containing H 2 S, CO 2 and CH 2 are highly corrosive to dam structure. H 2 SO 4 formed by oxidation of H 2 S attack the cement and disintegrate the concrete. These gases increase the solubility of soil and rocks. Structures, metallic piping and penstock are also affected.
3. Presence of Corrosive gases like H 2 S and SO 2 affect the voltage drop.
a) True
b) False
Answer: a
Explanation: Presence of Corrosive gases like H 2 S and SO 2 does affect the voltage drop at brush contacts in generator leading to poor commutation. Silver contacts of relays get blackened and lead to high contact resistance and failure of relay occurs.
4. Which among the following reduces the capacity of reservoir and causes rapid erosion of turbine blades?
a) Contamination of highly corrosive material
b) Sedimentation effect
c) Submerged vegetation
d) Solid contamination
Answer: b
Explanation: Sediments in the aquatic ecosystem are analogous to soil in the terrestrial ecosystem as they are the source of substrate nutrients, and micro- and macro flora and -fauna that are the basis of support to living aquatic resources.
5. What is the basic requirement of hydroelectric power station?
a) Reservoir
b) Turbine
c) Power house
d) Penstock
Answer: a
Explanation: The basic requirement of a hydroelectric power station is a reservoir where large quantity of water is stored during flood season and used during dry season. The reservoir is generally built of constructing dam across river.
6. The water from is drawn by the __________
a) Canal
b) Hose
c) Stream
d) Penstock
Answer: a
Explanation: The water from reservoir is drawn by the fore bay through an open canal or tunnel. The water from fore bay is supplied to water turbine through penstock which is located at much lower level than the height of water in reservoir.
7. What is used to prevent the entry of debris into turbine?
a) Wiper
b) Fore bay
c) Trash rack
d) Filter
Answer: c
Explanation: Trash rack is used to prevent the entry of debris which might damage the Wicket gate and turbine. It is a wooden or metal structure and is supported by masonry, that prevents waterborne debris from entering into penstock which than connects to turbine.
8. A pipe between surge tank and prime mover is known as?
a) Canal
b) Draft tube
c) Penstock
d) Hose
Answer: c
Explanation: A pipe between the surge tank and prime mover is known as penstock. It is made of steel through reinforced concrete. Cast iron is used for small plants. The intake of penstock at the dam or fore bay of canal should be positioned such that it always provides adequate water even at low level.
9. Which type of penstock is used in cold climates?
a) Buried penstock
b) Covered penstock
c) Open penstock
d) Exposed penstock
Answer: a
Explanation: Buried penstocks are used in cold climates where freezing is expected. types of penstocks have shorter life period. A buried penstock will not be subjected to the problem of harmonic vibrations sometimes associated with the traditional penstock.
10. Which type of penstocks is less expensive?
a) Buried penstock
b) Covered penstock
c) Open penstock
d) Exposed penstock
Answer: d
Explanation: Exposed penstocks are less expensive and have a longer life. Their inspection and maintenance is easier. Penstocks are not covered because exposed pipes are easily accessible. The water flow rate is 2, 4, and 7 m/s in low, medium and high head power plants respectively.
11. A safety valve for a dam to discharge major floods is called?
a) Spillway
b) Penstock
c) Fore bay
d) Canal
Answer: a
Explanation: Spillway is a safety valve for a dam to discharge major floods without damage to dam. It keeps the reservoir level below some predetermined maximum level. Spillway ensures that water does not overflow and damage or destroy the dam.
12. What is introduced between the dam and power house?
a) Penstock
b) Draft tube
c) Prime mover
d) Surge tank
Answer: d
Explanation: Surge tank is introduced between the dam and power house nearest to the power house and preferably on the high ground to reduce the height of tower to provide better regulation of water pressure in the system during variable load condition.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Classification of Hydro-Plant”.
1. What type of Hydro plant is it if the Plant head is above 100m?
a) High head hydro-plant
b) Medium head hydro-plant
c) Low head hydro-plant
d) Base load hydro-plant
Answer: a
Explanation: If the head of water available is above 100m, the plant is known as a high head plant. IN this head, water available for producing electricity is very high and it can extend to 1000 meters. These are most commonly constructed hydro plants.
2. Which type of hydro plant is it if the head of a hydro plant is 30 – 100m?
a) High head hydro-plant
b) Medium head hydro-plant
c) Low head hydro-plant
d) Base load hydro-plant
Answer: b
Explanation: If the water available is more than 30m but less than 100m, than this type of plant is known as medium head plant. Water stored in fore bay is conveyed to the turbine through penstocks. In these plants the river water is tapped off to a fore bay on one bank of rive.
3. Low head hydro plant is also known as ____________
a) Canal power plant
b) Medium head hydro-plant
c) Run-off river hydro-plant
d) Base load hydro plant
Answer: a
Explanation: Low head hydro electric power plant is also known as canal power plant. The dam in this type of power plant is of very small head may be even few meters only. The low head type of power plants cannot store water.
4. Which plants supply the peak load for the base power plants?
a) Mini hydel plants
b) Pump storage power plants
c) Low head plants
d) Run-off river power plants
Answer: b
Explanation: Pumped storage plants supply the peak load for the base power plants and pump all or a portion of their own water supply. The plant contains a tail water pond and a head water pond connected by a penstock.
5. Which plants are used with steam and IC engines?
a) Pumped storage plants
b) Mini hydel plants
c) Low head Hydel plant
d) Run-off river plants
Answer: a
Explanation: Pumped storage plants can be used with hydro, steam and IC engines. The generating pumping unit is at the lower end. During off peak hours some of the surplus electric energy generated by the base plant is utilized to pump water from tail water pond into the head water pond.
6. Which type of turbines does modern hydro power plant use?
a) Kaplan turbine
b) Francis turbine
c) Pelton wheel
d) Cross flow turbine
Answer: b
Explanation: Modern power plants use Francis turbine. Francis turbine is a water turbine developed by James Francis. It is an inward flow reaction turbine that combines radial and axial flow concepts. These are primarily used for electric production.
7. Which type of hydro power plant can be with or without pondage?
a) Mini hydel plants
b) Pump storage power plants
c) Low head plants
d) Run-off river power plants
Answer: d
Explanation: Run-off river power plants can be with or without pondage. A runoff river plant without pondage has no control over river flow and uses water as it comes. The runoff river plant with pondage may supply base load power.
8. The surge tank controls the water when the load on the turbine is ________
a) Equal
b) Decreased
c) Increased
d) Not present
Answer: b
Explanation: The surge tank controls the water when the load on the turbine decreases. The excess water is stored in the surge tank and hence the pressure variations in the penstock are taken care of preventing water hammer.
9. Which type of valves is preferred for moderate heads?
a) Butterfly valve
b) Tube valve
c) Needle vale
d) Globe valve
Answer: a
Explanation: For moderate heads butterfly valves are preferred. Gate valves are used to regulate the flow. This valve is used both as intake gate and as turbine valve. It helps inspection without dewatering the penstock line.
10. Which type of gate valves are used in high head installations?
a) Needle valves
b) Butterfly valves
c) Globe valve
d) Pinch valve
Answer: a
Explanation: Needle valves are used in high head installations. The needle valve consists of three water filled chambers A, B and C in which hydraulic pressures can be varied. The valves are opened and closed by varying the pressures in these chambers.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Atomic Structure”.
1. Why has nuclear energy become an inevitable option for the development of the country?
a) Because less pollution caused by nuclear plant
b) High efficiency of nuclear energy
c) Due to acute shortage of other sources of energy
d) High cost of energy production of other sources
Answer: c
Explanation: With the acute shortage of other sources of energy viz. fossil based fuels and hydel sources the use of nuclear energy has become an inevitable option for the both developed and developing country.
2. How much amount of nuclear energy burnt is equivalent to the energy produced by 3000 tonnes of coal?
a) 1kg
b) 5kg
c) 15kg
d) 20kg
Answer: a
Explanation: The amount of heat generated by burning one kg of nuclear fuel is equivalent to the energy generated by burning 3000 tonnes of coal or 1600 tonnes of oil. The production of Nuclear energy is carried out by two methods which are nuclear fission and nuclear fusion.
3. What is the most attractive part of nuclear energy?
a) Supports countries development
b) Causes no pollution
c) Has high efficiency of energy production
d) Is available in abundance
Answer: b
Explanation: Most attractive part of nuclear energy is that it has no combustion products and under safe working conditions contributes no pollutant to air. Site selection is completely independent of geographical area.
4. Nucleus consists of two sub-particles known as?
a) Nucleotides
b) Nucleons
c) Neutrons
d) Nucleosides
Answer: b
Explanation: Atom consists of a relatively heavy, positively charged nucleus and a number of much lighter negatively charged electrons. Electrons exist in various orbits around the nucleus. The nucleus consists of two sub-particles known as nucleons.
5. The atom as a whole is electrically charged.
a) True
b) False
Answer: b
Explanation: The atom as a whole is not electrically charged it is actually electrically neutral in its state. The electric charge on the proton is equal in magnitude but opposite in sign to that of electron, the number of protons is equal to the number of electrons in the orbit.
6. On which law is the nuclear energy explained?
a) Einstein’s law
b) Newton’s law
c) Rutherford law
d) Mendeleev law
Answer: a
Explanation: The nuclear energy is explained the basis of Einstein’s law, one atom may be transformed into another by losing or acquiring some of the above sub-particles. This results in mass change Δm and enormous amount of energy is released . According to Einstein’s law,
ΔE = Δmc 2
Where, c=light of speed.
7. Identify the element by its Atomic structure.
energy-engineering-questions-answers-atomic-structure-q7
a) Helium
b) Hydrogen
c) Carbon
d) Oxygen
Answer: b
Explanation:
Most of the mass of the atom is in nucleus. The red dot is a proton it has positive charge of 1 unit, and black one is an electron, which has a negative charge of -1. There is only one orbital for hydrogen.
8. Identify the element by its atomic structure?
energy-engineering-questions-answers-atomic-structure-q8
a) Hydrogen
b) Helium
c) Carbon
d) Oxygen
Answer: b
Explanation:
The masses of three atomic sub-particles are,
Neutron mass, m n = 1.008665 amu
Proton mass, m p = 1.007277 amu
Electron mass, m e = 0.0005486 amu.
9. Number of protons in the nucleus is called ___________
a) Atomic number
b) Mass number
c) Electric charge
d) Periodic number
Answer: a
Explanation: Number of protons in the nucleus is called atomic number Z. it is unique for each chemical element, and represents both the number of positive charges on the central massive nucleus of the atom and the number of electrons in orbits around the nucleus.
10. The total number of nucleons in the nucleus is called _________
a) Atomic number
b) Mass number
c) Electric charge
d) Periodic number
Answer: b
Explanation: The total number of nucleons in the nucleus is called the mass number A. Nuclear symbols are written as z X A Where X is chemical symbol. The masses of atoms are compared on a scale in which an isotope of 6 C 12 has a mass of exactly 12.
11. To disrupt a nucleus and separate in into its component nucleons, energy must be supplied from outside and this energy is called?
a) Bonding energy
b) Kinetic energy
c) Binding energy
d) Nuclear energy
Answer: c
Explanation: To disrupt a nucleus and separate in into its component nucleons, energy must be supplied from outside and this energy is called Binding energy. The nuclear force acts only when the nucleons are very close to each other and binds them into compact stable structure.
12. The net neutrons produced per initial neutron accounting for all possible losses is called?
a) Bombardment
b) Half life
c) Multiplication factors
d) Covalent bond
Answer: c
Explanation: The net neutrons produced per initial neutron accounting for all possible losses is called multiplication factor . If: K < 1 = system is subcritical.
K = 1 = System is critical.
K > 1 = system is super critical.
13. What is the time during which one half of a number of radioactive species decays or one half of their activity ceases?
a) Half Life
b) Super critical state
c) Semi life
d) Critical life
Answer: a
Explanation: Half life is the time during which one half of a number of radioactive species decays or one half of their activity ceases. It is also used to characterize any type of exponential and Non-exponential decay.
14. Electrons that orbit outermost shell of an atom are called?
a) Valence electrons
b) Electrons
c) Electron Coefficients
d) Neutrons
Answer: a
Explanation: Electrons that orbit outermost shell of an atom are called Valence electrons. The outermost shell is called valence shell. The presence of valence electron can determine the element’s chemical properties.
15. A covalent bond is also called as ____________
a) Atomic bond
b) Metal bond
c) Molecular bond
d) Metal bond
Answer: c
Explanation: A covalent bond is also called as molecular bond, which involves sharing of electron pairs between atoms. These electron pairs are known as shared pairs or bonding pairs, when these share an electron than it is called as covalent bonding.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Nuclear Fission & Nuclear Fusion”.
1. In which of the following process are Neutrons emitted?
a) Inverse beta Decay
b) Nuclear fission
c) Spontaneous Fission
d) Nuclear fusion
Answer: b
Explanation: Nuclear fission is the process in which a heavy nucleus is split into two or more lighter nuclei. This result in decrease in mass and consequent exothermic energy and emission of neutrons take place. Two to three neutrons are emitted per nucleuses which are known as fission elements.
2. Heavy nuclei must be such that they can be fissioned by neutrons of an energy such substance are called?
a) Fission fragments
b) Fission Neutrons
c) Fission species
d) Fission elements
Answer: c
Explanation: Heavy nuclei must be such that they can be fissioned by neutrons of energy such substance are called Fission species. All fission species should have long half lives so that the rate of decay is not so fast.
3. Why neutrons with lower energy should be capable of causing fission?
a) For faster reaction process
b) For sustained reaction process
c) For Safety purpose
d) In order to not waste the nuclear fuel
Answer: b
Explanation: Due to collisions with various nuclei, initial high kinetic energy of fission neutron decreases. Thus for a sustained reaction, eve neutrons with lower energy should be capable of causing fission. Only neutrons can result in sustained reaction as two or three neutrons are released for each one absorbed by fission.
4. What happens when a neutron is absorbed by a nucleus of an atom of U 235 ?
a) Mass number of atom increases
b) One electron is let out
c) U 236 isotope is formed
d) Nucleus becomes unstable
Answer: c
Explanation: When a neutron is absorbed by a nucleus of an atom U 235 , a U 236 isotope is formed. This isotope is highly unstable which lasts for one millionth of a second and splits into two equal parts releasing energy of 200MeV.
5. Who invented nuclear fission?
a) Rutherford
b) Hans Bethe
c) Otto Hahn
d) Marie Curie
Answer: c
Explanation: Nuclear fission of heavy metals was discovered by German Otto Hahn on December 17, 1938 and was explained theoretically by Lise Meitner and her nephew Otto Robert Frisch on 1939. Frisch named Frisch names the process by analogy with biological fission of living cells.
6. Atoms of different chemical elements that have the same number of nucleons are called as?
a) Isobars
b) Isotones
c) Isomers
d) Isotopes
Answer: a
Explanation: Atoms of different chemical elements that have the same number of nucleons are called as isobars. The term isobar was suggested by Alfred Walter Stewart in 1918. It is derived from Greek word ‘isos’ meaning EQUAL and ‘baros’ meaning WEIGHT.
7. Most of the energy released in fission process is in process of __________
a) Kinetic Energy
b) Thermal Energy
c) Light Energy
d) Heat Energy
Answer: a
Explanation: Most of the energy released is in the form of kinetic energy and is absorbed by fission products. The fission products formed are fission fragments, neutrons and electromagnetic or gamma radiation. As the fragments collide, the kinetic energy is converted into heat energy.
8. Combining of two light nuclei of low mass to produce a heavy nucleus is called ___________
a) Nuclear fusion
b) Nuclear fission
c) Spontaneous fission
d) Double beta decay
Answer: a
Explanation: Nuclear fusion is the process which involves fusion of two light nuclei of low mass to produce a heavy nucleus which results in decrease of mass and release of enormous amount of energy. All atomic bombs prefer nuclear fission process.
9. What type of Reaction takes place in sun?
a) Nuclear fusion
b) Nuclear fission
c) Spontaneous fission
d) Double beta decay
Answer: a
Explanation: Nuclear fusion reaction takes place in sun as well as stars. The process is carried by proton-proton chain. The sun starts with protons, and through a series of steps, turns them into helium. Every second 600 million tons of hydrogen is converted into helium. The reaction releases tremendous amount of heat and energy.
10. How many number of nuclei of hydrogen fuse in a series of reaction involving other particles that continually appear and disappear?
a) 1
b) 2
c) 3
d) 4
Answer: d
Explanation: Four nuclei of hydrogen fuse in a series of reaction involving other particles that continually appear and disappear such as He3, nitrogen, carbon and other nuclei.
4 1 H 1 → 2 He 4 + 2 +1 e 0
Mass decreases to about 0.0276amu releasing 25.7MeV. The heat liberated during this result in temperature of the order of the million degrees and sustains the succeeding reactions.
11. Why is it necessary to accelerate positively charged nuclei to high kinetic energies to cause fusion?
a) To overcome electrical repulsive forces
b) To result in high amount of energy in short period of time
c) To get the isobars and isotopes
d) To get a sustainable reaction
Answer: a
Explanation: To cause fusion, it is necessary to accelerate positively charged nuclei to high kinetic energies to overcome electrical repulsive forces. This is done by rising their temperatures to hundreds of millions of degree resulting in plasma.
12. Fusion reactions are called __________
a) Thermonuclear
b) Thermoduric
c) Thermo Uric
d) Compound reactions
Answer: a
Explanation: To eradicate repulsive forces temperature of positively charged nuclei is raised to millions of degree resulting in plasma. The plasma should be prevented from contacting the walls of the container confined for a period of time of the order of a second at a minimum density. Fusion reactions are called thermonuclear because of the higher temperature requirement to trigger and sustain the reaction.
13. Which of the following element is readily available in the ordinary water?
a) Cesium
b) Thorium
c) Deuterium
d) Astatine
Answer: c
Explanation: Deuterium used in fusion reaction is readily available in ordinary water . Deuterium is also known as heavy hydrogen. The nucleus of deuterium is called as deuteron, Contains one proton and one neutron.
14. How is tritium made from sea water?
a) By bombarding lithium
b) By bonding with carbon
c) By bombarding Beryllium
d) By reacting with oxygen
Answer: a
Explanation: Tritium is made by seawater by bombarding with lithium. Lithium is a chemical element with Atomic number: 3 and Mass number: 6.941 u ± 0.002 u. Because of its relative nuclear instability, lithium is less common in the solar system.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Nuclear Reactor Components”.
1. Which nuclear fuel is usually used in thermal nuclear reactor to create fission?
a) U 234
b) U 235
c) U 236
d) U 237
Answer: b
Explanation: In a thermal nuclear reactor the fission induced by neutrons using a fuel isotope U 235 is one of the several isotopes used in nuclear power generation. Fuel isotopes which are capable of being fissioned by thermal neutrons are called fissile’s.
2. 90 Th 232 is fertile isotope produced by fission.
a) True
b) False
Answer: a
Explanation: 90 Th 232 is a fertile isotope produced by nuclear fission. 90 Th has 6 naturally occurring isotopes, none of these isotopes are stable; however, one isotope, 232 Th is relatively stable, with a half life of 1.405× 10 10 years, considerably longer than the age of earth.
3. Which parts function is to reduce the energy of fast neutrons to thermal neutrons in nuclear power plant?
a) Moderator
b) Coolant circulator
c) Control rods
d) Shielding
Answer: a
Explanation: Function of moderator is to reduce the energy of fast neutrons to thermal neutrons. Due to high energy of fission neutrons relative to that required to trigger another fission event their probability of interacting with U 235 is small.
4. What makes the best moderators in nuclear power plant?
a) Material with low atomic number
b) Materials with low atomic mass
c) Materials with high atomic number
d) Materials with high mass number
Answer: a
Explanation: The moderator slows down the neutrons to thermal energies by collision with inert atoms . Speed of the neutrons is reduced within a small number of collisions as the moderator possesses a high scattering cross section. Materials with low atomic mass number make best moderators.
5. Select the desirable property of a moderator?
a) Moderator should absorb neutrons but slow down the neutrons as early as possible
b) It should have low thermal conductivity for better heat transfer
c) It shouldn’t be chemically unstable
d) It should have low resistance to corrosion
Answer: c
Explanation: It should be chemically stable and should not e decomposed due to nuclear radiation. It should not absorb neutrons but slow down the neutrons as early as possible. It should have high resistance to corrosion as it has to work under high pressure and temperature.
6. What is used in nuclear reactor as a cooling method/device?
a) Coolant
b) Water jackets
c) Air cooler
d) Air vents
Answer: a
Explanation: The coolant is used and its function is to remove the heat released by fission. The coolant should have high specific heat, high conductivity, good chemical stability, good pumping characteristics and low neutron absorption cross section. Coolant can either be liquid or gas.
7. Control rods are made of __________
a) Cesium
b) Cadmium
c) Tin
d) Gallium
Answer: b
Explanation: Control rods are made of cadmium or boron or Hafnium. They have huge neutron absorption cross sections. The control rods are lowered or raised in the reactor core. Control rods are used in control rod assemblies and inserted into the guide fuels within a fuel element.
8. Reactor power is directly proportional to neutron density.
a) True
b) False
Answer: a
Explanation: Reactor power is directly proportional to neutron density, lowering the control rods will remove neutron from the reactor core and will decrease the power and reaction rate and raising the control rods will increase the power and rate.
9. What types of rays are trapped by shielding?
a) Gamma rays
b) Beta rays
c) X-rays
d) IR rays
Answer: a
Explanation: Shielding prevents the passage of radiation to the outside of the reactor. The primary shield prevents the leakage of neutron and gamma radiation present in the cooling circuits due to activation of coolant as passes through the core.
10. Shield is made of _________
a) Iron Metal enclosure
b) Concrete and water
c) Ceramics walls
d) Copper metal
Answer: b
Explanation: Shield is frequently constructed in layers or heavy and light material like concrete and water. Shields for external circuit where only gamma radiation may be present is made up of steel, lead, polyethylene, concrete.
11. Which of the following part in a nuclear reactor minimizes the neutron leakage?
a) Shield
b) Control rods
c) Reflector
d) Moderator
Answer: c
Explanation: Function of the reflector is to minimize the neutron leakage by reflecting them back into the reactor. The material used for reflector is same as that used for moderator. It scatters the neutrons that leak from core and returns the neutrons back into core by reflecting them.
12. In which of the following reactor is fission caused by slow or thermal neutrons?
a) Thermal reactor
b) Burner reactor
c) Fast reactor
d) Breeder reactor
Answer: a
Explanation: A thermal reactor is a nuclear reactor that uses slow or thermal neutrons. Most nuclear power plants are thermal reactors and use neutron moderator to slow neutrons until they approach the average kinetic energy of the surrounding particles. Fission is caused by slow or thermal neutrons.
13. Which reactor has no moderator and its core size is less?
a) Fast reactor
b) Burner reactor
c) Thermal reactor
d) Breeder reactor
Answer: a
Explanation: A fast reactor is a category of nuclear reactor in which the fission chain reaction is sustained by fast neutrons, as opposed to thermal neutrons used in thermal neutron reactors. The fission process is caused by fast neutrons and the reactor has no moderator and the core size less.
14. In which reactor is fertile material converted into initial fissile material?
a) Breeder reactor
b) Fast reactor
c) Burner reactor
d) Thermal reactor
Answer: a
Explanation: A breeder reactor is a nuclear reactor that generates more fissile material than it consumes. In this reactor fertile material is converted into initial fissile material. For e.g. natural uranium is the fuel, thorium is converted into U 233 .
15. Which reactor produces only heat?
a) Burner reactor
b) Breeder reactor
c) Thermal reactor
d) Intermediate reactor
Answer: a
Explanation: Burner reactor is a type of reactor using U 235 as fuel. Enriched uranium is used to increase efficiency. To prolong the fission reaction, fast neutrons are slowed down with a moderator and the rate of reaction is adjusted by control rods which can absorb neutrons. Some neutrons react to form plutonium, but in smaller amounts than the original uranium, and produces only heat as a product.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Types of Nuclear Reactor & Nuclear Waste”.
1. PWR stands for ________
a) Power
b) Partially weathered rock
c) Pressurized water Reactor
d) Packaging waste regulations
Answer: c
Explanation: PWR stands for pressurized water reactor. A PWR power plant consists of two loops in series. One is the coolant loop called primary loop and other is the water steam or working fluid loop. Pressurized water reactor falls under the category of light water reactor.
2. What does the top of the pressurizer in pressurized water reactor consists of at primary system pressure?
a) Steam
b) Air
c) Water
d) Fluids
Answer: a
Explanation: The pressurizer is a pressure vessel with a heater at the bottom and water spray at the top. The top of the pressurizer is filled with steam at primary system pressure. If the primary loop pressure drops, the heater is energized to increase the steam content in the pressurizer and thus increases the pressure of primary cooling system.
3. Select the incorrect statement which supports PWR.
a) Water is used as coolant
b) PWR is stable in operation
c) Uses natural fuel
d) PWR has positive power demand coefficient
Answer: c
Explanation: PWR uses enriched fuel making the reactor more compact in size. And due to high negative temperature coefficient, a PWR is stable. Water is used as the coolant. It does have positive power demand coefficient and responds greatly to more power demand.
4. Select the incorrect statement about PWR.
a) High primary circuit pressure requires a strong pressure vessel
b) Corrosion is less in PWR
c) During fuel charging in PWR, the reactor has to be shut down at least for a month
d) PWR results in uneven heating
Answer: b
Explanation: Presence of high temperature and high pressure water, the corrosion is severe. This means use of stainless steel adds to further costing. When γ- radiations pass through the pressure vessel it results in uneven heating which induces thermal stresses on vessels.
5. LWR stands for _________
a) Lower water reactor
b) Line water reactor
c) Liquefied water reactor
d) Light water reactor
Answer: d
Explanation: The light water reactor is a type of thermal-neutron reactor that uses normal water, as opposed to heavy water, as both its coolant and neutron moderator – furthermore a solid fissile element is used as fuel. These are most common type of Thermal-neutron reactors.
6. In which reactor is the coolant in direct contact with the heat producing nuclear fuel?
a) Fast breeder reactor
b) Pressurized water reactor
c) Boiling water reactor
d) Heavy water reactor
Answer: c
Explanation: In boiling water reactor, the coolant is in direct contact with the heat producing nuclear fuel and boils in the same compartment in which the fuel is located. The reactor pressure is maintained at 70bar. The coolant thus serves the triple function of coolant, moderato and working fluid.
7. How many types of Boiling water reactor cycles are there?
a) 2
b) 3
c) 4
d) 5
Answer: b
Explanation: There are three different types of BWR cycles commonly used:
Single cycle internal circulation: This system uses internal recirculation system to generate power ranging from 50- 100 MW.
Single cycle forced circulation: This type uses a forced circulation system using a circulation system using a circulating pump. The heat in the reactor is used to generate steam.
Dual cycle forced circulation: this arrangement has two cycles, steam cycle and gas cycle.
8. Which country invented CANDU heavy water reactor?
a) Canada
b) Germany
c) Russia
d) Bolivia
Answer: a
Explanation: The CANDU is a Canadian pressurized heavy water reactor design used to generate electric power. Heavy water nuclear reactors and light water nuclear reactors differ in how they create and manage the complex physics of nuclear fission or atom-splitting which produces the energy and heat to create steam to drive generators.
9. In which of the Following reactor is heavy hydrogen isotope H-2 is used as moderator?
a) Boiling water reactor
b) Pressurized water reactor
c) Candu reactor
d) Thermal reactor
Answer: c
Explanation: Heavy water composed of heavy hydrogen isotope H-2 is used as a moderator and coolant in some power and research reactors. These reactors use heavy water as a moderator and primary coolant and light water as secondary coolant.
10. CANDU stands for ____________
a) Canadian Natural Darmstadtium Uranium
b) Canadian Natural Deuterium Uranium
c) Canadian Natural Dubnium Uranium
d) Canadian Natural Dysprosium Uranium
Answer: b
Explanation: The CANDU, for Canada Deuterium Uranium, is a Canadian pressurized heavy water reactor design used to generate electricity. The acronym refers to its deuterium oxide moderator and its use of Uranium fuel.
11. Which reactor consists of both fertile and fissile material?
a) Fast breeder reactor
b) Pressurize water reactor
c) Boiling Water reactor
d) Converter reactor
Answer: a
Explanation: If the reactor produces more fissionable material than it consumes, it is fast breeder reactor. The breeder fuel consists of both fertile and fissile material. The number of neutrons released is sufficient to propagate the fission reaction and to produce more fissionable material by conversion of fertile isotopes to fissile isotopes.
12. What is acronym of LMFBR?
a) Liquid molecular fast boiling reactor
b) Liquid metal fast breeder reactor
c) Liquefied metal fast boiling reactor
d) Liquid metal fast boiling reactor
Answer: b
Explanation: LMFBR stands for Liquid metal fast breeder reactor. The fuel consists of 80% by weight of UO 2 by weight of PuO 2 in small diameter stainless steel clad tubes operating at temperature of 670 o C – 700 o C.
13. GCFBR stands for ____________
a) Gas conditioned fast breeder reactor
b) Gas cooled fast breeder reactor
c) Gas conditioned fast boiling reactor
d) Gas cooled fast breeder reactor
Answer: b
Explanation: The GCFBR stands for Gas cooled fast breeder reactor; it is cooled by helium gas at 85bar. Also helium doesn’t become radioactive under neutron bombardment AND hence secondary coolant is not needed.
14. Using Helium gas in GCFBR has many advantages.
a) True
b) False
Answer: a
Explanation: Using helium as coolant posses less severe metallurgical and safety problems. Heat transfer coefficient of helium is much superior than sodium with artificial roughening of fuel rod surfaces. Low doubling time as compared to sodium cooled reactors.
15. Which reactor uses orthometaerhenyl and paratherphenyl as coolant and moderator?
a) Liquid metal fast breeder reactor
b) Gas cooled fast breeder reactor
c) Organic substance cooled reactor
d) CANDU Heavy water reactor
Answer: c
Explanation: Organic substance cooled reactor uses enriched uranium as fuel and a mixture of orthometaterhenyl and paratherphenyl as coolant and moderator, and boron control rods, generating 11.4 MW capacities with an overall efficiency of 25%.
16. Nuclear plant is located near the area where cooling water is available.
a) True
b) False
Answer: a
Explanation: Some of the major factors to locate a nuclear station considered are, Availability of cooling water, transportation facilities, Distance from load centre, safety, radioactive waste, disposal facility and foundation requirement.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Disposal of Nuclear Waste”.
1. What is the major problem in nuclear plants?
a) Drawing out energy
b) Fusion of particles
c) Disposal of nuclear waste
d) Handling of fuel
Answer: c
Explanation: One of the major problems in the nuclear power plant is the disposal of waste products which are highly radioactive. They emit large quantities of γrays and these high energy γ rays destroy all living matter through which pass.
2. A 400 MW nuclear power station would produce a equivalent radium of _____________
a) 100 tons daily
b) 1000 tons daily
c) 500 tons daily
d) 10 tons daily
Answer: a
Explanation: The radio-active products of a 400MW power station would be equivalent to 100 tons of radium daily and the radioactive effect of this plant product if exposed to atmosphere would kill all the living organisms within the area of about 100 sq miles.
3. How are moderate active solid wastes disposed?
a) Buried underground
b) Buried under sea
c) Sent to outer space
d) Left out in streams or rivers
Answer: a
Explanation: In a nuclear fuel cycle, the solid, liquid and gaseous radioactive wastes are produced at different stages. These radioactive wastes must be disposed off in such a manner that there is no hazard to the human and plant life. Moderate active solid wastes are buried in the ground.
4. Moderate liquid nuclear wastes are disposed into ___________
a) Deep pits
b) Buried underground
c) Left into rivers
d) Left into deep oceans
Answer: a
Explanation: Moderate liquid wastes after preliminary treatments are discharged in deep pits or day well from which they sweep out into the surrounding. Certainly liquid wastes are mixed with some kind of other chemical in order to lower their radioactivity.
5. Which type of disposal of nuclear waste is cheapest and easiest method of all?
a) Ground
b) Air
c) Space
d) Water
Answer: a
Explanation: This is one of the easy and cheapest methods of disposal because soil absorbs radioactive material easily. This disposal is suitable mostly in areas of low rainfall at points which are high above the ground water level.
6. How are active liquids of nuclear waste disposed?
a) Stored in concrete tanks and buried underground
b) Stored in concrete tanks and buried in sea
c) Mixed with other chemicals and left into free atmosphere
d) They are reused and burnt away in gaseous fumes
Answer: a
Explanation: Active liquids are kept in concrete tanks and these tanks are buried in the ground till their decay of radio activity. Many times the radio activity increases the temperature of the liquid waste or sometimes these liquids boil and the activity decreases with time.
7. What are the ways in which most of radio activeness is removed?
a) Infusing them with other metal
b) Neutralizing them by diluting in chemical solutions
c) Storing them
d) Segregating them into small packs
Answer: c
Explanation: Most of the radio activeness of waste is removed just by storage. The storage problem is simplified by separating cersium and strontium which are extremely radioactive. These are generally stored in tanks which are buried in ground and then disposed in to the sea after 13 years of storage.
8. Can vacated coal mines be used for waste disposal.
a) True
b) False
Answer: a
Explanation: Yes, vacated coal mines can be used for waste disposal. The wastes are disposed in the salt heaps provided in the mines, because salt is a powerful absorber of radioactive emissions. It will be easy and more economical method to dispose of liquid waste by freezing.
9. How is High Level solidified nuclear wastes stored?
a) Concrete tanks
b) Canisters
c) Packed rock salt
d) Soil bins
Answer: b
Explanation: The solidified waste is placed in canisters that are stored in holes formation for thousands of years. The solidified waste is placed in canisters that are stored in holes drilled in rock salt with a spacing of 10 m to allow efficient dissipation of energy without exceeding temperature limits of either canister or salt. Each canister requires 100 m 2 of salt for cooling.
energy-engineering-questions-answers-disposal-nuclear-waste-q9
10. What is the approx cost of disposing nuclear waste into sea per cubic meter?
a) 50 rs
b) 300 rs
c) 500 rs
d) 1000 rs
Answer: b
Explanation: In many places the liquid waste is disposed off to the sea through the pipes carried from the plant to the point of disposal. While disposing into the sea it should be seen that the activity level should not affect the marine life. The approximate cost of disposal by this method is 300 rs per cubic meter.
11. Absorption of radioactive element by human, affects their offspring’s.
a) True
b) False
Answer: a
Explanation: Absorption of neutron or radioactive element by a tissue nucleus leads to radioactive nucleus which results change in chemical nature, mal-functioning of cell. Due to this, cell damages leading to genetic modification. Inhale of radioactive material through air, food and water result radiation hazard.
12. For how many days is radioactive solid waste kept is kept under water at 6m deep for initial cooling?
a) 15 days
b) 50 days
c) 30 days
d) 100 days
Answer: d
Explanation: It is necessary to keep the radioactive solid waste first in the water of 6m depth nearly for 100 days. It was found that after 100 days cooling of radioactive waste of 28MW plant in water still has a radioactivity equal to million grams of radium. About 50% radioactive elements disappear during cooling.
13. What are released into biosphere from nuclear power plants?
a) Gaseous effluents
b) Waste Product
c) Smoke
d) The obtained product
Answer: a
Explanation: Under normal operation, gaseous effluents are released slowly from the power plants into the biosphere and become diluted and dispersed harmlessly. Releasing at slow rates gives it time to blow of slowly.
14. Tailings forms are the residues from ____________
a) Uranium
b) Thorium
c) Cadmium
d) Boron
Answer: a
Explanation: Tailings are residues from uranium mining and milling operations. They contain low concentration of naturally occurring radioactive materials. They are generated in large volumes and are stored at the mine or mill sites.
15. LLW stands for ____________
a) Low Level Water
b) Low Laser width
c) Low Level Waste
d) Loss of Levels in water
Answer: c
Explanation: Low Level Waste contains less than 10 nCi per gram of transuranium contaminants containing low but potentially hazardous concentrations of radioactive materials. These are generated in almost all activities involving radioactive materials, require little or no shielding.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Solar Radiation”.
1. Which of the following energy has the greatest potential among all the sources of renewable energy?
a) Solar energy
b) Wind Energy
c) Thermal energy
d) Hydro-electrical energy
Answer: a
Explanation: Solar energy has the greatest potential of all the sources of renewable energy which comes to the earth from sun. This energy keeps the temperature of the earth above that in colder space, causes wind currents in the ocean and the atmosphere, causes water cycle and generates photosynthesis in plants.
2. What is the rate of solar energy reaching the earth surface?
a) 1016W
b) 865W
c) 2854W
d) 1912W
Answer: a
Explanation: The solar energy reaching the surface of the earth is about 1016W whereas the worldwide power demand is 1013W. That means solar energy gives us 1000 times more energy than our requirement.
3. What is total amount of solar energy received by earth and atmosphere?
a) 3.8 X 1024 J/year
b) 9.2 X 1024 J/year
c) 5.4 X 1024 J/year
d) 2.1 X 1024 J/year
Answer: a
Explanation: Even if we use 5% of this energy, it is more than 50 times our requirement. The total solar radiation absorbed by the earth and its atmosphere is 3.8 X 1024 Joules/year. Except that it is distributed over the area of earth.
4. Which is most common source of energy from which electricity is produced?
a) Hydroelectricity
b) Wind energy
c) Coal
d) Solar energy
Answer: c
Explanation: Coal is the most common source of energy that is being used since industrialization. Modern steam boilers can burn coal in any of its form as a primary fuel. Different ranks of coal available are peat, lignite, bituminous and anthracite.
5. Oil is estimated to last for ________ more.
a) 100 years
b) 500 years
c) A decade
d) 800 years
Answer: a
Explanation: Almost 40% of energy needs is met by oil alone. With present consumption and a resource of 250,000 million tonnes of oil, it is estimated to be last for only 100 years, unless more oil is discovered. Major chunk of oil comes from petroleum.
6. Complete the following reaction.
H 2 O + CO 2 → _______
a) CH 2 O + O 2
b) CO 2 + O 2
c) H + CO 2 + O 2
d) CH 2 O + H 2 O + O 2
Answer: a
Explanation: H 2 O + CO 2 → CH 2 O + O 2 ∵under solar energy CH 2 O is stable at low temperature but breaks at higher temperature releasing heat equal to 469 Kj/mole.
7. In what form is solar energy is radiated from the sun?
a) Ultraviolet Radiation
b) Infrared radiation
c) Electromagnetic waves
d) Transverse waves
Answer: c
Explanation: Solar energy is radiated from the sun in the form of electromagnetic waves of shorter wavelength of 0.2 to 0.4 micrometers. Out of all the solar energy radiations reaching the earth’s atmosphere, 8% is ultraviolet radiation, 40% is visible range light and 46% is by infrared radiation.
8. What does MHD stands for in the energy field?
a) Magneto Hydro Dynamic
b) Metal Hydrogen Detox
c) Micro Hybrid Drive
d) Metering Head Differential
Answer: a
Explanation: Magneto hydro dynamic is a generator which is used for direct conversion of thermal energy into electrical energy. They work on faraday principle. When an electric conductor moves across a magnetic field, electric current is produced.
9. Solar radiation which reaches the surface without scattering or absorbed is called _____________
a) Beam Radiation
b) Infrared radiation
c) Ultraviolet radiation
d) Diffuse radiation
Answer: a
Explanation: Solar radiation that has not been absorbed or scattered and reaches the ground from the sun is called direct radiation or beam radiation. It is the radiation which produces a shadow when interrupted by an opaque object.
10. The scattered solar radiation is called ____________
a) Direct Radiation
b) Beam Radiation
c) Diffuse radiation
d) Infrared Radiation
Answer: c
Explanation: Diffuse radiation received from the sun after its direction has been changed by reflection and scattering by the atmosphere. Since the solar radiation is scattered in all direction in the atmosphere, diffuse radiation comes to the earth from all parts of the sky.
11. Solar radiation received at any point of earth is called ______________
a) Insolation
b) Beam Radiation
c) Diffuse Radiation
d) Infrared rays
Answer: a
Explanation: Insolation is the total solar radiation received at any point on any point on the earth’s surface. In other words insolation is the sum of the direct and diffuse radiation. More specifically insolation is defined as the total solar radiation energy received on a horizontal surface of unit area on the ground in unit time.
12. Insolation is less ____________
a) when the sun is low
b) when the sun right above head
c) at night
d) at sun rise
Answer: a
Explanation: The insolation at a given point or location on the earth’s surface depends among other factors, on the altitude of the sun in the sky. As a result of absorption and scattering, the insolation is less when the sun is low in the sky than when it is higher.
13. HHW stands for ____________
a) High and Low water
b) High Level Waste
c) Heated Low Level water
d) High and Low Waste
Answer: b
Explanation: These are generated in reprocessing of spent fuel. They contain all fission products and contain of the transuranium elements not separated during reprocessing. Such wastes are to be disposed of carefully.
14. What is unit of nuclear radiation?
a) Reaumur
b) Roentgen
c) Rankine
d) Pascal
Answer: b
Explanation: Units of nuclear radiation is Roentgen- amount of radiation which will on passing through pure air under standard condition produce 1 electrostatic unit of ions/cm 3 of air -> 86.9 ergs of energy absorbed/gm of air.
15. Which type of fuel is removed from the reactor core after reaching end of core life service?
a) Burnt Fuel
b) Spent fuel
c) Engine oil
d) Radioactive fuel
Answer: b
Explanation: Spent fuel is the unprocessed fuel that is removed from the reactor core after reaching end of core life service. It is removed and then stored for 3 to 4 months under water in the plant site to give time for the most intense radioactive isotopes to decay.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Solar Constant”.
1. The amount of energy received in unit time on a unit area perpendicular to the sun’s direction at the mean distance of the earth from the sun is called ________
a) Solar radiation
b) Solar constant
c) Intensity of solar radiation
d) Air Mass
Answer: b
Explanation: The amount of energy received in unit time on a unit area perpendicular to the sun’s direction at the mean distance of the earth from the sun is called solar radiation. It is defined as the solar energy receiving at the top of the atmosphere, denoted by I sc .
2. What is ‘n’ in the following solar intensity formula?
I = I sc {1 + 0.033cos }
a) Day of the year
b) Month of the year
c) The year
d) Week of the year
Answer: a
Explanation: The following ‘n’ denotes day of the year in the formula. Since the distance between sun and earth varies, extra-terrestrial flux also varies. Earth is closest to the sun in the summer and farthest away in the winter.
3. When the sun is directly on the top of head, it as referred to _________
a) Zenith
b) Azimuth
c) Declination
d) Hour angle
Answer: a
Explanation: When the sun is directly on the top of the head, it is referred to as sun at zenith. The zenith is an imaginary point directly “above” a particular location, on the imaginary celestial sphere. The zenith is the “highest” point on the celestial sphere.
4. Path length of radiation through the atmosphere to the length of path when the sun is at zenith is called ___________
a) Declination
b) Air mass
c) Azimuth
d) Solar Constant
Answer: b
Explanation: Path length of radiation through the atmosphere to the length of path when the sun is at zenith is called Air mass.
Air mass, m = Cos , except for very low solar altitude angles.
m = 1; When the sun is at the zenith
m = 2; When zenith angle is 60 o
m = 3; sec (θ z ) for m>3.
5. Radiation intensity ‘I’ normal to the surface is given by __________
a) ICosθ
b) Itanθ
c) ICotθ
d) Isinθ
Answer: a
Explanation: I = ICosθ, Let θ = Angle between an incident beam radiation I and the normal to the plane surface. And the θ is referred to as incident angle. And further by this formula latitude angle, declination, hour angle, zenith angle and solar azimuth angles are found out.
6. Angle made by radial line joining the location to the centre of the earth with the projection of the line on the equatorial plane is called _________
a) Latitude
b) Zenith angle
c) Hour angle
d) Declination
Answer: a
Explanation: Angle made by radial line joining the location to the centre of the earth with the projection of the line on the equatorial plane is called latitude. And it is denoted by Φ l . It is also given by the angular distance north or south of the equator measured from the centre of the earth.
7. Angular distance of sun’s rays north or south of the equator is called _______
a) Declination
b) Hour angle
c) Latitude
d) Air mass
Answer: a
Explanation: Declination is the angular distance of sun’s rays north or south of the equator. It is the angle between the line extending from the centre of the sun to the centre of the earth and the projection of this line upon earth’s equatorial plane.
8. By which of the following symbol is solar Declination denoted by ____________
a) δ
b) ρ
c) Δ
d) γ
Answer: a
Explanation: Solar declination is denoted by Greek letter δ. Solar declination is the angle between the earth-sun line and the equatorial plane. Solar declination varies throughout the year. And is given by cooper equation,
δ = 23.45sin [ ] ∵n is day of the year.
9. The angle through which the earth must turn to bring the meridian of a point directly in sun’s rays is called __________
a) Hour angle
b) Declination
c) Latitude
d) Air mass
Answer: a
Explanation: The angle through which the earth must turn to bring the meridian of a point directly in sun’s rays is called Hour angle. And it is denoted by Greek letter ω . It is measured from noon based on the solar local time .
10. Solar Altitude is also called as ________
a) Declination
b) Altitude angle
c) Zenith angle
d) Azimuth angle
Answer: b
Explanation: The vertical angle between the projection of the sun’s rays on the horizontal plane and the direction of sun’s rays passing through the point s called solar altitude and is also referred to altitude angle and is denoted by Greek letter α .
11. The angle between the sun’s rays and a line perpendicular to the horizontal plane through angle the beam of the sun and vertical is called __________
a) Solar Azimuth angle
b) Zenith angle
c) Altitude angle
d) Declination
Answer: b
Explanation: The angle between the sun’s rays and a line perpendicular to the horizontal plane through angle measured from the north to the horizontal projection of rays is called zenith angle. And it is denoted by θ z .
12. The solar angle in degrees along the horizon east or west of north or it is the horizontal angle measured from north to the horizontal projection of sun’s rays is called ___________
a) Solar azimuth angle
b) Zenith angle
c) Altitude angle
d) Declination
Answer: a
Explanation: The solar angle in degrees along the horizon east or west of north or it is the horizontal angle measured from north to the horizontal projection of sun’s rays is called solar azimuth angle. And it is denoted by Greek letter γ s .
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Solar Radiation Measurement”.
1. Angle made by plane surface with horizontal is called ________
a) Slope
b) Altitude angle
c) Zenith angle
d) Hour Angle
Answer: a
Explanation: The slope is the angle made by the plane surfaces with the horizontal. It is considered positive for surfaces slopping towards the south and negative for surface slopping towards the north. Different types of measurements are calculated by slopes.
2. The angle of deviation of the normal to the surface from the local meridian is called as _________
a) Surface azimuth angle
b) Solar azimuth angle
c) Solar altitude
d) Hour angle
Answer: a
Explanation: Surface azimuth angle is the angle of deviation of the normal to the surface from the local meridian, the zero point being south, east positive and west negative. And surface azimuth is different where it is an angle on a horizontal plane between the normal to a vertical surface and the north-south direction line.
3. The angle being measured from a plane and which is equal to angle between the beam of rays and normal to the plane is called __________
a) Incident angle
b) Azimuth angle
c) Hour angle
d) Declination
Answer: a
Explanation: The angle being measured from a plane and which is equal to angle between the beam of rays and normal to the plane is called as incident angle. And it is denoted by Greek letter θ . The angle of incidence is the angle between the sun’s rays irradiated on a surface and the line normal to this surface.
4. The vector sum of the components along the line normal of the titled surface in a direction normal to the tilted surface is called as __________
a) Solar intensity
b) Declination
c) Incident angle
d) Hour angle
Answer: a
Explanation: The solar intensity at a direction normal to the tilted surface is the vector sum of the components along the line normal of the tilted surface. And is given by formula,
I Σ = I DN cosθ Σ
Where I DN = solar intensity irradiated on a surface normal to the sun’s rays.
5. The time from sunrise to sunset is termed as _______________
a) Slope
b) Day length
c) Local solar time
d) Solar intensity
Answer: b
Explanation: The time from sunrise to sunset is termed as day length. On earth, daytime is roughly the period of the day during which any given point in the world experiences natural illumination from especially direct sunlight. Daytime occurs when the sun appears above the local horizon, that is, anywhere on the globe’s hemisphere facing the Sun. During daytime, an observer sees indirect sunlight while in the shade, which includes cloud cover.
6. LST stands for __________
a) Local standard time
b) Local solar temperature
c) Low surface temperature
d) Land surface temperature
Answer: b
Explanation: Local solar time is also known as local apparent time which is the time used for calculating the hour angle. The local solar time is obtained from the standard time observed on a clock by making two corrections. First, is taking different longitudes between the locations and second is correction due to small perturbations of earth’s orbit and rate of rotation.
7. How much would be the angle of declination on DECEMBER 21 at 0900 h . The collector s located in New Delhi (28 o 35’N, 77 o 12’E) and is tilted at an angle of 36 o with the horizontal and is pointing south?
a) -44.28 o
b) -28.92 o
c) -23.45 o
d) -42.22 o
Answer: c
Explanation: In the case γ = 0 o , on December 21, n=355
energy-engineering-questions-answers-solar-radiation-measurement-q7
8. What is angle of declination on 305 th day of year and what day is it?
a) -23.26 o , November 2
b) -15.06 o , November 1
c) -18.96 o , November 2
d) -10.52 o , November 1
Answer: b
Explanation: Angle of declination on 305 th day of the year i.e. on NOVEMBER 1
energy-engineering-questions-answers-solar-radiation-measurement-q8
9. What is the angle of declination on May 12 considering it’s a leap year?
a) 20.34 o
b) 22.85 o
c) 29.42 o
d) 12.4 o
Answer: a
Explanation: Angle of declination on May 21 in leap year is 142 nd day of the year.
energy-engineering-questions-answers-solar-radiation-measurement-q9
10. What is the angle of declination on 60 th day of the leap year?
a) -8.29
b) 8.29
c) 4.82
d) 12.44
Answer: a
Explanation: The date is February 29 on leap year, which is considered as the 60 th day.
energy-engineering-questions-answers-solar-radiation-measurement-q10
11. Which type of device is used to measure solar irradiance on a planar surface?
a) Pyranometer
b) Net radiometer
c) Gardon gauge
d) Pyrheliometer
Answer: a
Explanation: A Pyranometer is a type of actinometer used for measuring solar irradiance on a planar surface and it is designed to measure the solar radiation flux density from the hemisphere above within a wavelength range 0.3μm to 3μm.
12. Instrument used to measure direct beam of solar irradiance is called ____________
a) Pyranometer
b) Net radiometer
c) Gardon gauge
d) Pyrheliometer
Answer: d
Explanation: A Pyrheliometer is the device used to measure direct beam solar irradiance. Sunlight enters the instrument through a window and is directed onto a thermopile which converts heat to an electrical signal that can be recorded.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Flat Plate Collectors”.
1. To how many types are flat plate collectors divided depending on type of heat transfer fluid?
a) 2
b) 3
c) 4
d) 5
Answer: a
Explanation: Based on the type of heat transfer fluid, flat plate collectors are divided into two types, they are Liquid Heating Collectors and Air or gas heating collectors. And also happens that all other types of collectors come under these two types.
2. For what purpose are Gas heating collectors used?
a) To trap solar radiance
b) To act as a medium to help in conversion of sunlight to electrical energy
c) Employed as solar air heaters
d) They act as alternate panels in case of failure
Answer: c
Explanation: Air or Gas heating collectors are employed as solar air heaters. Solar air heater is a type of system driving outdoor air through a sealed, sun heated collector mounted on an exterior wall or roof, returning the warmed air back to the living space.
3. Liquid heating collectors are mainly used for _________
a) heating water
b) generating electricity
c) cooking
d) trapping sunlight
Answer: a
Explanation: Liquid heating collectors are mainly used for heating water. A liquid based solar collector is a solar collector that uses sunlight to heat a liquid that is circulating in a solar loop. The fluid in the solar loop may be water, an anti freeze mixture or thermal oil.
4. _______ is a glazing which limits the radiation and convection heat losses.
a) Absorber plate
b) Selective surface
c) Insulation
d) Transparent cover
Answer: d
Explanation: A transparent cover is glazing which limits the radiation and heat convection losses. It includes one or more sheets of glass or radiation transmitting plastic film or sheet. The glass itself is always a single pane adding to adding the second reduces the collector efficiency.
5. What are provided to minimize heat loss?
a) Absorber plate
b) Surface plate
c) Insulation
d) Casing
Answer: c
Explanation: Insulation is provided at the back and sides to minimize heat losses. Fiber glass or styro-foam is used for this purpose. And also most modern collectors use standard insulators such as polyurethane or polyisocynurate.
6. Which part of flat plate collectors is coated in black?
a) Transparent cover
b) Absorber plate
c) Insulation
d) Fins
Answer: b
Explanation: Absorber plate is usually metallic or coated in black surface which is used for absorbing radiation energy. The absorber plate’s coating directly affects how efficient the collector is. Coatings always have two rating figures: how much they absorb and how much they emit.
7. The frame which contains all the parts is called __________
a) box
b) plate
c) enclose
d) container
Answer: d
Explanation: Container is used to enclose the other components to protect them from weather. These containers are made of extruded aluminum which can be quite heavy and thick for heavy duty collectors. There are some collectors which are enclosed by fiber glass too.
8. In which collector does air flow without any obstruction?
a) Porous absorber plate
b) Non-porous absorber plate
c) Over lapped glass absorber
d) Finned absorber
Answer: b
Explanation: In a simple flat plate air collector, commonly known as non-porous absorbers, the air stream flow through the absorber plate without any obstruction. An analysis of black painted solar air collectors in conventional design in which the air flows below the absorber plate has been made.
9. In which absorber matrix material is arranged and the back absorber plate is eliminated?
a) Porous absorber plate
b) Non-porous absorber plate
c) Over lapped glass absorber
d) Finned absorber
Answer: a
Explanation: In the porous bed air heater, the matrix material is arranged and the back absorber plate is eliminated. A single glazed porous bed collector with a reflecting honey comb, extending above the porous to just under the glass cover have theoretically examined.
10. Which type of absorber increases the heat transfer area over a simple flat plate absorber of the same capacity?
a) Porous absorber plate
b) Non-porous absorber plate
c) Over lapped glass absorber
d) Finned absorber
Answer: d
Explanation: The finned plate absorber increases the heat transfer area over a simple flat absorber of same capacity. A good design of a finned absorber can increase the heat transfer rate. The temperature difference between the absorber plate and air is very low.
11. In which type of absorber plate is the overall flow direction is along the absorber glass plate?
a) Overlapped glass absorber
b) Finned absorber
c) Non-porous absorber plate
d) Porous absorber plate
Answer: a
Explanation: In overlapped absorber plate, overall flow direction is along the absorber glass plate instead of being across the matrix. Plate and air stream temperature increase gradually along the collector length and across from top to bottom.
12. How is heat loss over come in liquid plate collectors?
a) By insulation
b) By casing
c) By the transparent cover
d) From provided tubes
Answer: a
Explanation: Heat is transferred from the absorber plate to a point of use by the circulating fluid via water across the solar heated surface. The heat loss from the surface is prevented by placing thermal insulation of 5 to 10cm thickness behind the absorber plate.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Generation of Wind Energy”.
1. What does Heating and cooling of the atmosphere generates?
a) Thermo line circulation
b) Radiation currents
c) Convection currents
d) Conduction currents
Answer: c
Explanation: Wind energy can be economically used for the generation of electrical energy. Heating and cooling of the atmosphere generates convection currents. Heating is caused by the absorption of solar energy on the earth surface.
2. How much is the energy available in the winds over the earth surface is estimated to be?
a) 2.9 X 120 MW
b) 1.6 X 107 MW
c) 1 MW
d) 5MW
Answer: b
Explanation: The energy available in the winds over the earth surface is estimated to be 1.6 X 107 MW which is almost the same as the present day energy consumption. Wind energy can be utilized to run wind mill which in turn, is used to drive the generators.
3. How much wind power does India hold?
a) 20,000 MW
b) 12,000 MW
c) 140,000 MW
d) 5000 MW
Answer: a
Explanation: India has a potential of 20,000 MW of wind power. Wind power accounts nearly 9.87% of India’s total installed power generation capacity. Generation of wind power in India mainly account from southern state of India.
4. What is the main source for the formation of wind?
a) Uneven land
b) Sun
c) Vegetation
d) Seasons
Answer: b
Explanation: Wind is free and renewable form of energy, which throughout history has been used to grind grain, power ships, and pump water. Wind is created when the sun unevenly heat the earth surface.
5. Which country created wind mills?
a) Egypt
b) Mongolia
c) Iran
d) Japan
Answer: c
Explanation: The earliest known wind mills were in Persia . These early wind mills looked like large paddle wheels. Centuries later, the people of Holland improved the basic design of wind mill. Holland is famous for its wind mills.
6. “During the day, the air above the land heats up more quickly than the air over water”.
a) True
b) False
Answer: a
Explanation: During the day, the air above the land heats up more quickly than the air over water. The warm air over the land expands and raises, and the heavier, cooler air rushes in to take its place, creating winds.
7. What happens when the land near the earth’s equator is heated?
a) All the oceans gets heated up
b) Small wind currents are formed
c) Rise in tides
d) Large atmospheric winds are created
Answer: d
Explanation: The large atmospheric winds that circle the earth are created because the land near the earth’s equator is heated more by the sun than the land near the north and south poles. Wind energy is mainly used to generate electricity.
8. What type of energy is wind energy?
a) Renewable energy
b) Non-renewable energy
c) Conventional energy
d) Commercial energy
Answer: a
Explanation: Wind is called a renewable energy source because the wind will blow as long as the shines. Wind power, as an alternative to burning fossil fuels, is plentiful, renewable, widely distributed, clean, produces no greenhouse gas emissions during operation, consumes no water, and uses little land.
9. What are used to turn wind energy into electrical energy?
a) Turbine
b) Generators
c) Yaw motor
d) Blades
Answer: a
Explanation: Wind turbine blades capture wind energy, a form of mechanical energy, and put it to work turning a drive shaft, gearbox, and generator to produce electrical energy. Many factors affects wind turbine efficiency including turbine blade aerodynamics.
10. What is the diameter of wind turbine blades?
a) 320 feet
b) 220 feet
c) 80 feet
d) 500 feet
Answer: b
Explanation: Large utility-scale wind turbines can now generate more than a MW of electrical power each and deliver electricity directly in to the electric grid, these turbines are placed at 200 feet height at the rotor hub and have blades which are 220 feet or more in diameter.
11. At what range of speed is the electricity from the wind turbine is generated?
a) 100 – 125 mph
b) 450 – 650 mph
c) 250 – 450 mph
d) 30-35 mph
Answer: d
Explanation: Wind turbines are designed with cut-in wind speeds and cut-out speeds i.e. the wind speeds when the turbines start turning or shut off to prevent drive train damage. Typically, maximum electric generations occurs at speeds of 30-35mph.
12. When did the development of wind power in India began?
a) 1965
b) 1954
c) 1990
d) 1985
Answer: c
Explanation: The development of wind power in India began in 1990s. Presently India is the world’s fourth largest wind power generator. The Indian energy sector has an installed capacity of 32.72 GW. Today India is a major player in the global wind energy market.
This set of Energy Engineering Questions and Answers for Aptitude test focuses on “Components of Wind Energy Conversion System”.
1. How much power does the small scale wind machine generate?
a) 18 KW
b) 2 KW
c) 12 KW
d) 30 KW
Answer: b
Explanation: These might be used on farms remote applications and other places requiring relatively low power. The generating capacity is up to 2kW. Small scale wind machines lower your electricity bills by 50% – 90%.
2. Which type of wind machines are used at several residence or local use?
a) Large size machines
b) Remote machines
c) Small size machines
d) Medium size machines
Answer: d
Explanation: These wind turbines may be used to supply less than 100 kW rated capacity, to several residences or local use. These do not require much space they can be installed on roof tops or on some high elevated areas.
3. Which type of wind turbines produce 100 kW or greater?
a) Large machines
b) Small machines
c) Medium machines
d) Remote Machines
Answer: a
Explanation: Large wind turbines are those of 100 kW rated capacity or greater. They are used to generate power for distribution in central power grids. They can have single generator at a single site or multiple generators sited at several places over an area.
4. Which part of the wind mill acts as a housing for the turbine?
a) Wind Vane
b) Shaft
c) Wind mill head
d) Turbine
Answer: c
Explanation: The wind mill head supports the rotor, housing, and rotor bearings. It also has control mechanism like changing the pitch of the blades for safety devices, tail vane to orient the rotor to face the wind. Its body is the size of the mini bus.
5. A rotor installed in a fixed orientation with the swept area perpendicular to the pre dominate wind direction is called ___________
a) Nacelle
b) Yaw fixed machines
c) Blades
d) Anemometer
Answer: b
Explanation: In the locations with the prevailing wind in one direction, the design of a turbine can be greatly simplified. The rotor can be installed in a fixed orientation with the swept area perpendicular to the pre dominate wind direction. This machine is called yaw fixed.
6. How is the action of yaw controlled in small turbines?
a) Tail vane
b) Blades
c) Shaft
d) Yaw motor
Answer: a
Explanation: In small turbines, yaw action is controlled by a tail vane while is larger machines a servomechanism operated by a wind-direction sensor controls the yaw motor keeping the turbine properly oriented.
7. Which part of the wind turbines senses wind speed, wind direction, shaft speed and torque?
a) Turbine blade
b) Shaft
c) Rotor
d) Controller
Answer: d
Explanation: The controller senses wind speed, wind direction, shafts speeds and torques, output power and generator temperature, Control signals are generated with the electrical output corresponding to the wind energy input.
8. Which type of wind turbine has low RPM?
a) Small wind turbine
b) Large wind turbine
c) Medium wind turbine
d) Remote wind turbine
Answer: b
Explanation: The rate of rotation of large wind turbine generators operating at rated capacity or below is controlled by varying the pitch of the rotor blades. It has low rpm, about 40 to 50. It is necessary to increase greatly the low rotor rate of turning using transmission mechanism.
9. Why recommendation of fixed ratio gears done for top mounted equipment?
a) Because they are easy install
b) Requires less space
c) Due to its low cost
d) Because of their high efficiency
Answer: d
Explanation: Fixed ratio gears are recommended for top mounted equipment because of their high efficiency, and minimum system risk. For bottom mounted equipment requiring a right angle drive transmission costs can be reduced on the hub by increasing rotor speed to generator.
10. Which type of generator are made use in wind turbines?
a) Recreational generators
b) Synchronous generator
c) Asynchronous generator
d) Alternator
Answer: b
Explanation: Generators may be either constant or variable speed type. Variable speed units are expensive and/or unproved. Constant speed generator in use are synchronous induction and permanent magnet types. Synchronous unit is used for large aero generator systems. It is very versatile and has an extensive data base.
11. In which part do we find sensors and actuators?
a) Fixed gears
b) Turbines
c) Control systems
d) Blades
Answer: c
Explanation: Control systems involves sensors and actuators. The modern large wind turbine generator requires a versatile and reliable control system. A control system is used for i) changing the orientation of the rotor into the wind. ii) Start up and cut-in of the equipment. iii) Power control of the rotor by varying the pitch of the blades.
12. How many types of supporting tower for wind mill are generally used?
a) 2
b) 4
c) 3
d) 5
Answer: b
Explanation: Four types of generating tower are used generally:
i) The reinforced concrete tower
ii) The pole tower
iii) The built up shell tube tower
iv) The truss tower.
13. On what does the selection of supporting structure depends?
a) Length of blades
b) Rotating capacity
c) Capacity of generator
d) Transmission systems
Answer: d
Explanation: The type of the supporting structure and its height is related to cost and the transmission system incorporated. Horizontal axis wind turbines are mounted on towers so as to be above the level of turbulence and other ground related effects.
14. At what type of location vibrations are more in the wind turbine?
a) Downwind location
b) Up wind location
c) Windward
d) Leeward
Answer: b
Explanation: In the upwind location , the wake of the passing rotor blades causes repeated changes in the wind forces on the wind forces on the tower. Due to this the tower may vibrate and may eventually be damaged.
15. At what type of location vibrations are less in the wind turbines?
a) Windward
b) Leeward
c) Downwind location
d) Upwind Location
Answer: c
Explanation: If the turbine is downwind from the tower, vibrations are less but the blades are subjected to severe alternating forces as they pass through the tower wake. Downwind rotors are generally preferred for large aero generators.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Velocity and Power from Wind”.
1. Select the formula for total power p t ?
a) P t = \(\frac{1}{2gc}\) ρAV i 3
b) P t = ρAV i 3 D 3
c) P t = \(\frac{1}{2gc}\) V i 3 D 3
d) P t = \(\frac{2gc}{Vi^3}\)
Answer: a
Explanation:
energy-engineering-questions-answers-velocity-power-wind-q1-exp
2. Why blade velocity of wind turbine varies?
a) Due to varying wind speeds
b) Long length of blades
c) Due to the height of mount
d) Because of hotness of Sun
Answer: b
Explanation: Wind turbine experiences change in velocity dependent upon the blade inlet angle and the blade velocity. Since the blades are long, the blade velocity varies with the radius to a greater degree than steam or gas-turbine blades and the blades are therefore twisted.
3. When was the Halladay wind mill introduced?
a) 1920
b) 1923
c) 1854
d) 1864
Answer: c
Explanation: Invented by Daniel Halladay in 1854, the Halladay Standard was the first commercially successful self-governing windmill in 1854 was the firms of Halladay, McCray & Co., Ellington, Conn. Partners in the company were inventor Daniel Halladay, John Burnham and Henry McCray.
4. How much ideal efficiency should practical turbine have?
a) 10 – 12%
b) 18 – 25%
c) 80 – 90%
d) 50 – 70%
Answer: d
Explanation: As wind turbine wheel cannot be completely closed, and because of spillage and other effects, practical turbines have 50 to 70% of the ideal efficiency. The real efficiency η is the product of this and ηmax and is the ratio of an actual to total power.
P = ηP tot .
5. How many types are acting on propeller type wind mill?
a) 2
b) 3
c) 4
d) 5
Answer: a
Explanation: There are two types of forces operating on the blades of a propeller type wind turbine. They are the circumferential forces in the direction of wheel rotation that provide the torque and the axial forces in the direction of the wind stream that provide an axial thrust that must be counteracted by proper mechanical design.
6. Calculate the air density, when 10m/s wind is at 1std atmospheric pressure and 15 o C?
a) 1.226 kg/m 3
b) 1.033 kg/m 3
c) 2.108 kg/m 3
d) 0.922 kg/m 3
Answer: a
Explanation: For air, gas constant R = 287 J/kgK, 1atm = 1.01325 X 10 5 Pa
Air density, ρ = P/RT = (1.01325 ×10 5 )/) = 1.226 kg/m 3 .
7. Calculate the air density when 18m/s wind is at 1std atmospheric pressure and 34 o C?
a) 1.149 kg/m 3
b) 1.9 kg/m 3
c) 2.88 kg/m 3
d) 5.89 kg/m 3
Answer: a
Explanation: For air, gas constant R = 287 J/kgK, 1atm = 1.01325 X 10 5 Pa
Air density, ρ = P/RT = (1.01325 × 10 5 )/) = 1.149 kg/m 3 .
8. What is the total power produced if the turbine diameter is 120m?
a) 0.277 KW
b) 1.224 KW
c) 4.28 KW
d) 0.89 KW
Answer: a
Explanation: Total power P,
P = 0.245 X (πD 2 /4)
= 0.245 X 2 /4)
= 0.277 KW.
9. What is the total power produced if the turbine diameter is 90m?
a) 0.155KW
b) 0.982 KW
c) 1.452 KW
d) 3.12 KW
Answer: a
Explanation: Total power P,
P = 0.245 X (πD 2 /4)
= 0.245 X 2 /4)
= 0.155KW.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Wind Turbine Operation”.
1. What is the inherent weakness of all wind machines?
a) Their efficiencies
b) Requires powerful winds to make fan rotate
c) Their dependency on the wind speed
d) Cannot be easily repaired
Answer: c
Explanation: An inherent weakness of all wind machines are the strong dependence of the power produced on wheel diameter and wind speed, being proportional to turbine wheel area, i.e. to the square of its diameter and to the cube of wind velocity.
2. Why severe fluctuations in power are always undesirable in windmill?
a) Because they pose power oscillations problems
b) Damage of parts due to fluctuations
c) The efficiency of the plant will be reduced
d) Results in damage to the whole plant
Answer: a
Explanation: Severe fluctuations in power are always undesirable, because they pose power oscillation problems on the grid and severe strains on the windmill hardware. From an economic point of view, a windmill is designed to produce a rated power output corresponding to maximum, or near maximum, prevailing wind velocity at a given site would generate low powers, with full capacity of the turbine and electric generator unused much of time.
3. Maintenance of constant output at all wind speeds above rating is called _________
a) Numeric rating scale
b) Tenancy
c) Flat Rating
d) TRP
Answer: c
Explanation: More cost-effective design to a wind mill to produce rated power at less than the maximum prevailing wind velocity, using a smaller turbine and generator and to maintain a constant output at all wind speeds above rating. This is called flat rating.
4. A wind turbine designed too to come into operation at a minimum wind speed is called _________
a) Cut in velocity
b) Windward
c) Cut out velocity
d) Upwind location
Answer: a
Explanation: Due to several loss in efficiency and power at low wind velocities, a wind turbine is designed to come into operation at a minimum wind speed called the cut in velocity. Thus the wind turbine operates with variable load over a narrow range between cut in.
5. Why is wind turbine designed to stop operation at cut out velocity?
a) To protect wheel against damage
b) To make a quick stop in emergencies
c) To improve the efficiency
d) In order to adjust the blades to wind direction
Answer: a
Explanation: To protect the turbine wheel against damage at very high wind velocities, it is designed to stop operation at cut out velocity. Thus the wind turbine operates at rated velocities and at constant power between the rated and cut out velocities and ceases the operation above the cut out velocity.
6. The fraction of time during a given period that the turbine is actually on line is called?
a) Availability factor
b) Flat rating
c) Cut in velocity
d) Cut out velocity
Answer: a
Explanation: The availability factor is defined as the fraction of time during a given period that the turbine is actually on line. The actual wind velocity at the propeller hub that determines the turbine power is usually higher.
7. Over load factor is also called as _____________
a) availability factor
b) plant operating factor
c) flat rating
d) cut out velocity
Answer: a
Explanation: The overall load factor, also called the plant operating factor and the plant capacity factor is the ratio of the total energy generated during a given period of time to the total rated generation capacity during the same period.
8. How many of windmills are there?
a) 2
b) 3
c) 4
d) 5
Answer: a
Explanation: There are two classes of windmill, horizontal axis and vertical axis. The vertical axis design was popular during the early development of the windmill. However, its inefficiency of operation let to the development of numerous horizontal axis designs.
9. Name the windmill which has four blades mounted on a central post.
a) Post mill
b) Smock mill
c) Tower mill
d) Fan mill
Answer: a
Explanation: The post mill has blades mounted on a central post. The horizontal shaft of the blade is connected to a large break wheel. The break wheel interacts with a gear system, called the wallower, which rotates a central, vertical shaft. This motion can then be used to power water pumping or grain grinding activities.
10. Name the type of windmill which consists of a sloping, horizontally weather boarded or thatched tower.
a) Post mill
b) Smock mill
c) Tower mill
d) Fan mill
Answer: b
Explanation: The smock mill is a type of windmill that consists of a sloping, horizontally weather boarded or thatched tower, usually with six or eight sides. It is topped with a roof or cap that rotates to bring the sails into the wind. It is similar to post mill. It is named so because of its appearance.
11. Which are further improvements on smock mill?
a) Post mill
b) Smock mill
c) Tower mill
d) Fan mill
Answer: c
Explanation: Tower mills are further improvements on smock mills. They have a rotating cap and permanent body, but this body is made of brick or stone. This fact makes it possible for the towers to be rounded. A round structure of it allows for large and taller towers.
12. Which type of windmills are been used for primary purposes?
a) Post mill
b) Smock mill
c) Tower mill
d) Fan mill
Answer: d
Explanation: The fan type windmill is specifically made for individuals. It is much smaller and used primarily for pumping water. It consists of a fixed tower , a wheel and tail assembly , a head assembly, and a pump.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Horizontal Axis Wind Mill”.
1. In which of the following, does machine rotor drives through a step up gear box?
a) Horizontal axis with two aerodynamic blades
b) Horizontal axis propeller type wind mill
c) Horizontal axis multi bladed type wind mill
d) Sail type wind mill
Answer: a
Explanation: In horizontal axis with two aerodynamic type windmill the machine rotor drives through a step up gear box. The blade rotor is designed to orient downwind of the tower. The components are mounted on bed plate which is attached on a pintle at the top of the tower.
2. The rotor blades are continuously flexed by unsteady aerodynamic gravitational and inertia loads.
a) True
b) False
Answer: a
Explanation: The rotor blades are continuously flexed by unsteady aerodynamic gravitational and inertia loads, when the machine is in operation. If the blades are made using metal, flexing reduces their fatigue life.
3. Which type of the following consists of single blade?
a) Horizontal axis with two aerodynamic blades
b) Horizontal axis propeller type wind mill
c) Horizontal axis multi bladed type wind mill
d) Sail type wind mill
Answer: b
Explanation: Horizontal axis propeller type wind mill consists of a long blade mounted on a rigid hub, induction generator and gear box. If extremely long blades are mounted on rigid hub, large blade root bending moments occur due to tower shadow, gravity and sudden shifts in wind directions.
4. Which windmill blades are made by an array of wooden slats?
a) Horizontal axis with two aerodynamic blades
b) Horizontal axis propeller type wind mill
c) Horizontal axis multi bladed type wind mill
d) Horizontal axis wind mill Dutch type
Answer: d
Explanation: Dutch type wind mill is one of the oldest wind mills in designs. The blade surfaces are made from an array of wooden slats which rotates at high wind speeds. These types of wind mill are cheap to build since the wood is made use of to build.
5. Which type of windmill blades are made out of sheet metal or aluminum?
a) Horizontal axis with two aerodynamic blades
b) Horizontal axis propeller type wind mill
c) Horizontal axis multi bladed type wind mill
d) Sail type wind mill
Answer: c
Explanation: Horizontal axis multi blade windmill is made from sheet metal or aluminum. The rotors have high strength to weight ratios. They have good power coefficient, high starting torque and added advantages of simplicity and low cost.
6. Which type of wind mills blade are made out of cloth?
a) Horizontal axis with two aerodynamic blades
b) Horizontal axis propeller type wind mill
c) Horizontal axis multi bladed type wind mill
d) Sail type wind mill
Answer: d
Explanation: The blade surface of sail type wind mill is made of cloth, nylon or plastics arranged as mast and pole or sail wings. There is also variation in the number of sails used. Sails are found in different designs, from primitive common sails to the advances patent sails.
7. Which type of windmill has better performance?
a) Vertical type wind mills
b) Darrieus type machines
c) Magnus effect rotor
d) Horizontal type windmills
Answer: d
Explanation: The horizontal axis mills generally have netter performance. They have been used for various applications including electric power generation, and pumping water. The latter introduces some complexity into the design as the mechanical energy has to be transmitted over a distance.
8. What does TSR stand for in design consideration of wind mills?
a) Tip speed ratio
b) Torque-synchronous ratio
c) Tip suspension ratio
d) Temporary speed restriction
Answer: a
Explanation: The tip speed ratio, X, or TSR for wind turbines is the ratio between the tangential speed of the tip of a blade and the actual speed of the wind. The tip speed ratio is related to efficiency, with the optimum varying with blade design.
9. With upto how many propellers can windmills are built?
a) 4
b) 2
c) 7
d) 6
Answer: d
Explanation: Wind turbines have been built with upto six propellers type blades but two and three bladed propellers are most common. A one bladed rotor with a balancing counter weight has some advantages, including lower weight and cost and simpler controls, over the multi-bladed type.
10. Turbines with how many propellers are used in order to avoid vibrations?
a) 1
b) 2
c) 3
d) 4
Answer: c
Explanation: Turbines with three blades are used to avoid vibrations that occur due to the turning or yawing of the rotor in order to face in into the wind. However, this problem can be overcome by controlling the yaw rate.
11. What type of cross sections does wind turbine blades have?
a) Penta hedral cross section
b) Air foiled type cross section
c) Radar cross section
d) Turbo cross section
Answer: b
Explanation: Wind turbine blades have an air foiled type of cross section and a variable pitch. They are slightly twisted from the outer tip to the root in order to reduce the tendency for the rotor to stall. The blades can also have constant chord length.
12. What does WECS stands for?
a) Wind energy conversion system
b) Wind engine control system
c) Wind energy combined system
d) Wind engine comparison system
Answer: a
Explanation: A wind energy conversion system , or wind energy harvester is a machine that, powered by the energy of the wind, generates mechanical energy that can be used to directly power machinery or to power an electrical generator for making electricity.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Vertical Axis Wind Mill”.
1. In which wind measuring device a tubular piece of thin flexible fabric hanged vertically to determine direction?
a) Wind socks
b) Weather vane
c) Pin wheels
d) Anemometers
Answer: a
Explanation: Wind sock is a very basic device that measure wind direction and provide a rough idea of the wind’s intensity. A wind sock is a tubular piece of fabric or thin, flexible fabric attached to a pole. When there is no wind, the fabric hangs vertically from the attached pole.
2. A device which is used as device for showing direction wind as well used as a decorative purpose?
a) Wind socks
b) Weather vane
c) Pin wheels
d) Anemometers
Answer: b
Explanation: A weather vane works similarly to wind sock. Instead of a tubular sock, the weather vane is made by placing a horizontal pole at the top of vertical pole. The poles are joined together so that the horizontal pole has a flattened, vertical end that reacts to wind.
3. Which is the wind direction showing device that spins perpendicularly?
a) Wind socks
b) Weather vane
c) Pin wheels
d) Anemometers
Answer: c
Explanation: A pinwheel is a windmill-style turbine that spins perpendicularly to the wind affecting it. Like wind socks and weather vanes, a pinwheel can be attached to a rotating base. This allows the pinwheel to change direction with the wind, and it will spin facing into the oncoming wind.
4. Which is the device that measures wind direction and its intensity?
a) Wind socks
b) Weather vane
c) Pin wheels
d) Anemometers
Answer: d
Explanation: An anemometer is any device that measures wind direction and intensity. It may be simple, such as the devices described above, or it may be a complex, computer-aided machine that measures and records wind patterns over time. More advanced anemometer machines are used to aid in professional weather reporting and air traffic control.
5. What units does the anemometer measure in?
a) Feet per minute
b) Liters per minute
c) Centimeters per minute
d) Meter per seconds
Answer: a
Explanation: The anemometer measures in feet per minute, or FPM. The rotation is sensed by a magnetic or optical sensor that converts the signal to FPM measurement. An arrow on the vane head identifies the direction the airflow must travel through the vane to obtain proper measurements.
6. Which of the following type of turbine or the rotor requires relatively low velocity winds for operation?
a) Cup anemometer
b) Savonius rotor
c) Darrieus type rotor
d) Magnus effect rotor
Answer: b
Explanation: Savonius rotor is a simple WEC system which woks like a cup anemometer. This type was invented by S.J. Savonius in the year 1920. It requires relatively low velocity winds for operation. It consists of two half cylinders facing opposite directions forming as S-shaped cross section.
7. Which type of axis does a Savonius Rotor has?
a) Horizontal axis
b) Mediolateral axis
c) Vertical axis
d) Lateral Axis
Answer: c
Explanation: A Savonius wind energy conversion system has a vertical axis and hence eliminates the expensive power transmission system from the rotor to the axis. Since it is a vertical axis machine it does not matter much about the wind direction.
8. Why is Savonius rotor not suitable for installation?
a) Because of long drive shaft
b) Because of its low capacity motor
c) Because of its typical blade design
d) Due to the light material it is made of
Answer: a
Explanation: Savonius rotor is not useful for very high installation because of long drive shaft problems. Bracing of the topmost bearing above the rotor of a very tall vertical axis machine is difficult requiring very long guy wires.
9. When was the Darrieus type machine invented?
a) 1925
b) 1932
c) 1929
d) 1948
Answer: a
Explanation: Darrieus type machine was invented originally and patented in 1925 by G.J.M > Darrieus, a French engineer. The Darrieus wind mill is a vertical axis machine that has the same advantage of a modern rapidly rotating propeller type windmill, by use of an efficient airfoil, effectively intercepts large area of wind with a small blade area.
10. What form of force acts on the blades of Darrieus machine?
a) Pure tension
b) Compression
c) Shear force
d) Air resistance force
Answer: a
Explanation: Darrieus wind mill has two or three thin, curved blades with airfoil cross section and constant chord length. Both ends of blades are attached to a vertical shaft. Thus the force in the blade due to rotation is pure tension.
11. Which type of vertical wind machine has relatively low solidity and low starting torques?
a) Cup anemometer
b) Savonius rotor
c) Darrieus type rotor
d) Magnus effect rotor
Answer: c
Explanation: Darrieus type rotors are lift devices characterized by curved blades with air foil cross sections. They have relatively low solidity and low starting torques, but high tip to wind speeds and therefore relatively high power outputs per given rotor weight and cost.
12. Which type of vertical wind machine consists of spinning cylinders?
a) Cup anemometer
b) Savonius rotor
c) Darrieus type rotor
d) Magnus effect rotor
Answer: d
Explanation: Magnus effect rotor concept was first demonstrated by Magnus in 1912. It consists of spinning cylinders. When cylinders spun in wind stream, translational forces are produced perpendicular to the wind stream by the Magnus effect. Such a device can be used to propel ships or land vehicles.
13. Aero turbine is the fraction of power in the wind through the swept area which is converted into useful mechanical shaft power is called _____________
a) Coefficient of performance
b) Coefficient of variation
c) Coefficient of lift
d) Coefficient of spin
Answer: a
Explanation: The coefficient of performance of an aero turbine is the fraction of power in the wind through the swept area which is converted into useful mechanical shaft power. C p for horizontal axis wind machine has theoretical maximum value = 0.593.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Tidal Power”.
1. How many basins does a single pool tidal system have?
a) 1
b) 2
c) 3
d) 4
Answer: a
Explanation: The simple single pool tidal system has one pool or basin behind a dam that is filled from the ocean at high tide and emptied to it at low tide. Both filling and emptying processes take place during short periods of time.
2. How much energy is estimated as total tidal power that is generated throughout the world?
a) 2.4 X 10 6 MW
b) 8.3 X 10 6 MW
c) 4.9 X 10 6 MW
d) 12 X 10 6 MW
Answer: a
Explanation: The total tidal power that is dissipated throughout the world is estimated at 2.4 X 10 6 MW of these some 10 6 MW are dissipated in shallow seas and coastal areas and are not recoverable. Because of very high cost of dams and other structures associated with tide energy conversion system, only a small amount of the rest can be satisfied by tidal energy.
3. What is time period for one tide to occur in a day?
a) 6h, 12.5 min
b) 6h, 40.5 min
c) 6h, 0 min
d) 6h, 25.6 min
Answer: a
Explanation: The flow of water in both directions is used to drive a number of reversible water turbines, each driving an electrical generator. Electric power would thus be generated during two short periods each tidal period of 12h, 25min or once every 6h, 12.5 min.
4. How many high peaks occur in a single pool tidal system?
a) 1
b) 2
c) 3
d) 4
Answer: b
Explanation: In the simple single pool system two high peaks, short duration power outputs occur every tidal period. Such peaks require large turbine-generators that remain idle much of the time. The power peaks also occur at different times every day , at times of high and low tides.
5. What happens if the turbine generators are smaller and operate much longer?
a) Resulting work is reduced
b) High power generation
c) Less power loss
d) Less sound is created
Answer: a
Explanation: Because the average head h is lower and work and power are proportional to h 2, turbine generators are much smaller and operate over a much longer period. The resulting total work is reduced.
6. On what is two-pool tidal system is less dependent?
a) Barrage
b) Tidal fluctuation
c) Reservoir
d) Gravitational force
Answer: b
Explanation: The two pool tidal system is less dependent on tidal fluctuation but is more complex and involves more costly dam construction. An inland basin is enclosed by dam A and is divided into a high pool and a low pool by dam B.
7. How much must be the tidal range over barrage to be feasible?
a) 7 meters
b) 25 meters
c) 10 meters
d) 20 meters
Answer: a
Explanation: The tidal range must be at least 7 meters for a barrage to be feasible. There are only three commercial-size barrage systems operating: one in France , one in Nova Scotia , and one in Russia .
8. Any location where the fresh water meets salty water is called _________
a) Dredging
b) River
c) Delta
d) Estuary
Answer: d
Explanation: Any location where fresh river water meets salty ocean water. The word “estuary” is derived from the Latin word aestuarium meaning tidal inlet of the sea, which in itself is derived from the term aestus, meaning tide. Estuaries are critical habitat for spawning and early life cycle stages of many ocean organisms as well as birds.
9. What tide of tide is it called when two high tides and two low tides of approximately equal size occur?
a) Diurnal tide
b) Spring tide
c) Neap tide
d) Semi-Diurnal tide
Answer: d
Explanation: An area has a semidiurnal tidal cycle if it experiences two high and two low tides of approximately equal size every lunar day. Semidiurnal tides may have daily inequity, where successive high tides have different heights.
10. Difference between water height at high tide and water height at low tide is called _______
a) Tidal Variation
b) Tidal volume
c) Tidal Range
d) Tidal Current
Answer: c
Explanation: The tidal range is the vertical difference between the high tide and the succeeding low tide. Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon and the Sun and the rotation of the Earth.
11. What is the movement of water generated by or associated with the change in mean sea level called?
a) Tidal Variation
b) Tidal volume
c) Tidal Range
d) Tidal Current
Answer: d
Explanation: Movement of water generated by or associated with the change in mean sea level is called tidal currents. Tidal currents occur in conjunction with the rise and fall of the tide. The vertical motion of the tides near the shore causes the water to move horizontally, creating currents.
12. What is the movement of water away from the shore called?
a) Flood tide
b) Spring tide
c) Ebb tide
d) Neap tide
Answer: c
Explanation: Movement of water away from the shore is called ebb tide. Ebb tide means the period between high tide and low tide during which water flows away from the shore, the receding or outgoing tide. The period between high water and the succeeding low water.
13. What is the term used for transport of non-cohesive sediments?
a) Dirt drop
b) Flick
c) Littoral drift
d) Droplet drifts
Answer: c
Explanation: Littoral transport is the term used for the transport of non-cohesive sediments, i.e. mainly sand, along the foreshore and the shore face due to the action of the breaking waves and the long shore currents.
14. Name the process of excavation activity usually carried underwater of purpose of gathering up bottom sediments.
a) Police drag
b) Dredging
c) Auger suction
d) Anti-eutrophication
Answer: b
Explanation: Dredging is an excavation activity usually carried out underwater, in shallow seas or freshwater areas with the purpose of gathering up bottom sediments and widening. This technique is often used to keep waterways navigable and creates an anti sludge pathway.
15. One Terra-watt is equal ______________
a) 1 trillion-watts
b) 100 trillion-watts
c) 5 trillion-watts
d) 10 trillion-watts
Answer: a
Explanation: One terra-watt is equal to 1 trillion watts. One terawatt hour of energy is equal to a sustained power delivery of approximately 114 megawatts for a period of one year. The watt second is a unit of energy, equal to the joule. One kilowatt hour is 3,600,000 watt seconds.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Tidal Energy”.
1. How is OTEC caused?
a) By wind energy
b) By geothermal energy
c) By solar energy
d) By gravitational force
Answer: c
Explanation: OTEC is caused by solar energy indirectly. Of late harnessing tidal and wave energy has gained momentum. While OTEC has its own limitations, wave and tidal energy conversion systems can generate more energy when compared to solar energy.
2. What does OTEC stand for?
a) Ocean thermal energy cultivation
b) Ocean thermal energy conversion
c) Ocean techno energy conservation
d) Ocean thermal energy consumption
Answer: b
Explanation: Ocean thermal energy conversion uses the temperature difference between cooler deep and warmer shallow or surface sea water to run a heat engine and produce useful work, usually in the form of electricity. OTEC can operate with a very high capacity factor and so can operate in base mode.
3. Which country has world’s largest tidal power plant?
a) Netherlands
b) South Korea
c) Laos
d) Bolivia
Answer: b
Explanation: Sihwa Lake Tidal Power Station is the world’s largest tidal power installation, with a total power output capacity of 254 MW. When completed in 2011, it surpassed the 240 MW Rance Tidal Power Station which was the world’s largest for 45 years. It is operated by the Korea Water Resources Corporation.
4. Which type of turbine is commonly used in tidal energy?
a) Francis turbine
b) Kaplan turbine
c) Pelton wheel
d) Gorlov turbine
Answer: b
Explanation: The Kaplan turbine is a propeller type reaction turbine that is usually immersed completely in the fluid it derives energy from. A Kaplan turbine is beneficial in that it is able to operate in lower pressure situations where Pelton or Francis turbines cannot.
5. How is water trapped from coastal waters?
a) By building canals
b) By building dams
c) By digging wells
d) By storing in tanks
Answer: b
Explanation: The tides are one of the sources of energy from the oceans. This energy can be tapped from coastal waters by building dams. Dams entrap the water at high tide and release it at low tide back to the sea.
6. Water to the turbine is allowed through the __________
a) Pipes
b) Sluice gates
c) Canals
d) Pumps
Answer: b
Explanation: A sluice is a water channel controlled at its head by a gate. A sluice gate is traditionally a wood or metal barrier sliding in grooves that are set in the sides of the waterway. Sluice gates commonly control water levels and flow rates in rivers and canals.
7. The tides are rhythmic and constant.
a) True
b) False
Answer: b
Explanation: The tides are rhythmic but not constant. They do not occur on a regular daily schedule. Their occurrence is due to balance of forces, mainly the gravitational force of the moon but also that of the sun, both acting together with that of earth to balance the centrifugal force on the water to the earth’s rotation.
8. For exactly how much time does it take for one tidal cycle?
a) 22h, 20min
b) 24h, 50min
c) 20h, 10min
d) 22h, 50min
Answer: b
Explanation: It takes the Earth an extra 50 minutes to catch up to the moon. Since the Earth rotates through two tidal bulges every lunar day, we experience two high and two low tides every 24 hours and 50 minutes. Here, we see the relationship between the tidal cycle and the lunar day.
9. What type of tide is it if the difference between high and low tide is greatest?
a) Diurnal tide
b) Neap tide
c) Spring tide
d) Ebb tide
Answer: c
Explanation: The tide that occurs when the difference between high and low tides is greatest. It occurs when the moon is new or full. Spring tides result when the gravitation forces of the sun and moon are parallel to one another.
10. A tide whose difference between high and low tides is least is called as __________
a) Diurnal tide
b) Neap tide
c) Spring tide
d) Ebb tide
Answer: b
Explanation: A tide that occurs when the difference between high tide and low tide is the least. Neap tides occur when gravitational forces from the sun and moon are at right angles to one another.
11. Which of the turbine can be mounted vertically and horizontally?
a) Pelton wheel
b) Kaplan turbine
c) Gorlov turbine
d) Francis turbine
Answer: c
Explanation: The Gorlov helical turbine is a water turbine evolved from Darrieus turbine design by altering it to have helical blades/foils. Gorlov turbine can be mounted both vertically and horizontally because it is not directional.
12. What types of tides occur when there is so much interference with continents?
a) Diurnal tide
b) Neap tide
c) Spring tide
d) Ebb tide
Answer: a
Explanation: Diurnal tides occur when there is so much interference by continents, only one high tide and one low tide occur per day. This diurnal tide has a period of 24 hrs and 50 min. An area has a diurnal tidal cycle if it experiences one high and one low tide every lunar day.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Wave Energy”.
1. Kinetic energy that results from the oscillation of water is called ________
a) Wave energy
b) Tidal energy
c) Ocean thermal energy
d) Hydro energy
Answer: a
Explanation: Kinetic energy that results from the oscillation of water is called wave energy. Wave energy is derived from wind energy, which derives in turn from solar energy. Wave energy can be much more concentrated than the solar energy.
2. How is height of wave determined?
a) By wind speed
b) By force of wave
c) By a immersion scale
d) By a floating device
Answer: a
Explanation: Wave height is determined by wind speed, the duration of time the wind has been blowing, fetch and by the depth and topography of the seafloor. A given wind speed has a matching practical limit over which time or distance will not produce larger waves.
3. What does oscillatory motion at ocean produce?
a) Microseisms
b) Froth
c) Disturbance of currents
d) Currents
Answer: a
Explanation: Oscillatory motion is highest at the surface and diminishes exponentially with depth. However, for near a reflecting coast, wave energy is also present as pressure oscillations at great depth, producing microseisms.
4. Waves are caused indirectly by ______
a) Wind energy
b) Solar energy
c) Geo-thermal energy
d) Wave energy
Answer: b
Explanation: Like the wind and OTEC, ocean and sea waves are caused indirectly by solar energy. Waves are caused by the wind, which in turn is caused by the uneven solar heating and subsequent cooling of the earth’s crust and the rotation of the earth.
5. Select the correct formula of potential energy in wave energy?
a) \
PE = \
\
\(\frac{PE}{A} = \frac{1}{4}\)ρa 2 × g
Answer: a
Explanation: \(\frac{PE}{A} = \frac{1}{4}ρa^2 × \frac{g}{g_c}\) is the correct formula for the potential energy of a wave.
g = gravitational acceleration, m/s 2
g c = conversion factor
ρ = water density
a = amplitude
A = λL in J/m 2 .
6. Select the correct formula of kinetic energy of a wave?
a) \
KE = \
KE = \
\(\frac{KE}{A} = \frac{1}{4}ρa^2\)
Answer: a
Explanation: The correct formula for kinetic energy of a wave is \(\frac{KE}{A} = \frac{1}{4}ρa^2 × \frac{g}{g_c}\).
g = gravitational acceleration, m/s 2
g c = conversion factor
ρ = water density
a = amplitude
A = λL in J/m 2 .
7. What are used to reduce to reduce the motion of floats?
a) Back pressure
b) Tubes
c) Damping fins
d) Anchor
Answer: c
Explanation: Damping fins are used to reduce the motion of the floats. The platform is stabilized within the water by four large underwater floatation tanks so that it is supported by the buoyancy forces. The floatation tank’s surfaces are wider in appearance and are flat.
8. From what material is the float made of _____________
a) Molded plastic
b) Thermocole
c) Stainless steel
d) Tubes
Answer: a
Explanation: The platform is made of molded plastic with s foamed plastic core to arrive at the required density and strength. It is also called float since it floats on the water. And it is in shape of cylinder with wide and flat bottom surface.
9. A _______ attached to the float moves up and down inside a cylinder.
a) chain
b) barrel
c) piston
d) load
Answer: c
Explanation: A piston attached to the float moves up and down inside a cylinder, fixed to the platform and is therefore relatively stationary. This piston cylinder arrangement is used as a reciprocating air compressor.
10. What type of energy is wave energy?
a) Non – conventional
b) Commercial
c) Non – renewable
d) Exhaustible
Answer: a
Explanation: Wave energy is free and non-conventional source of energy. Harnessing of energy by this method is relatively pollution free and because they remove energy from the waves, leaves the water in a relatively placid state in their wakes.
11. What is major disadvantage of wave energy?
a) It is not efficient enough
b) It is available only in ocean
c) The harnessing cost is more
d) Unstable during high wind pressures
Answer: b
Explanation: The major disadvantage of wave energy is that the energy is available on the ocean. The extraction equipment must be operated in a marine environment with all that implies in terms of maintenance, construction cost, life time and reliability.
12. Motion of water in a wave is primarily ________
a) Vertical
b) Horizontal
c) Linear
d) Opposite
Answer: a
Explanation: Wave motion is primarily horizontal but the motion of the water is vertical. Mechanical power is obtained by floats making use of the motion of water. The concept visualizes a large force that is driven up and down by the water within relatively stationary guides.
13. How many number of manifolds are part of a platform of floating device?
a) 1
b) 2
c) 3
d) 4
Answer: d
Explanation: There are four manifolds that are part of a platform. There are four large under water floatation tanks which stabilize the platform. Platform is supported by buoyancy forces and no vertical or horizontal displacement occurs due to wave action.
14. Which device uses the float which has two motions?
a) High level reservoir wave machine
b) Dolphin type wave generator
c) Hydraulic accumulator
d) Float wave power conversion device
Answer: b
Explanation: Dolphin type uses the float which has two motions. The first is a rolling motion about its own fulcrum with the connecting rod. Revolving movements are caused between the float and the connecting road. The other is nearly vertical or heaving motion about the connecting rod fulcrum.
15. In which wave machine instead of compressing air, the water itself is pressurized?
a) High level reservoir wave machine
b) Dolphin type wave generator
c) Hydraulic accumulator
d) Float wave power conversion device
Answer: c
Explanation: Hydraulic accumulator wave machines, instead of compressing air, the water itself is pressurized and stored in a high pressure accumulator or pumped to a high level reservoir, from which it flows through a water turbine electric generator.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Ocean Thermal Energy Conversion”.
1. Which is the type of energy where the energy is harnessed by the heat accumulated on the surface of water?
a) Wind energy
b) Wave energy
c) Ocean thermal energy conversion
d) Solar energy
Answer: c
Explanation: Absorption of heat from the sun by the seas and oceans, solar radiation causes ocean currents and moderate temperature gradients from the water surface downward especially in tropical waters.
2. Water _________ decreases with an increase in temperature.
a) volume
b) density
c) pressure
d) force
Answer: b
Explanation: Water density decreases with an increase in temperature. Thus, there will be no thermal convection currents between the warmer, lighter water at the top and the deep cooler, heavier water. Thermal conduction heat transfer between them, across the large depths, is too low and thus mixing is retarded, so the warm water stays at the top and cool water stays at the bottom.
3. How many essentially infinite heat reservoirs are present in tropical waters?
a) 1
b) 2
c) 3
d) 4
Answer: b
Explanation: In tropical waters, there are two essentially infinite heat reservoirs, a heat source at the surface at about 27 o C and heat sink some 1 Km directly below, at about 4 o C, both reservoirs are maintained by solar incidence.
4. Who first recognized the OTEC?
a) d’Arsonval
b) Alexander Edmond Becquerel
c) James Prescott joule
d) LA Rance
Answer: a
Explanation: The concept of ocean temperature energy conversion is based on the utilization of temperature difference in a heat engine to generate power. It was first recognized by Frenchman d’Arsonval in the year 1881.
5. From which cycle does maximum possible efficiency of a heat engine operating between two temperature limits cannot exceed?
a) Carnot cycle
b) Otto cycle
c) Open cycle
d) Anderson cycle
Answer: a
Explanation: The maximum possible efficiency of a heat engine operating between two temperature limits cannot exceed that of a Carnot cycle operating between the same temperature limits. The Carnot efficiency is given by
η c = (T 1 -T 2 )/T 1 .
6. Which of the following has the lowest efficiency?
a) Solar energy
b) Wind energy
c) Wave energy
d) OTEC
Answer: d
Explanation: OTEC power generation gives less efficiency. However, because of the OTEC requirement for parasitic power and other losses, the achievable net conversion efficiencies of 30 to 40% associated with conventional power plants.
7. The Claude cycle is also called as __________
a) Open cycle
b) Anderson cycle
c) Closed cycle
d) Otto cycle
Answer: a
Explanation: A Claude cycle is also called as open cycle in which sea water itself plays, the multiple role of heat source, working fluid and heat sink. In this cycle warm water at 27°C is admitted into an evaporator in which the pressure is maintained at a value slightly below the saturation pressure corresponding to that of water temperature.
8. Anderson cycle is also known as _________
a) Open cycle
b) Claude cycle
c) Closed cycle
d) Otto cycle
Answer: c
Explanation: Anderson cycle is also called as closed cycle. Closed cycle utilizes the oceans warm surface and cool deep waters heat source and sink respectively, but requires a separate working fluid that receives and rejects heat to the source and sink via heat exchanges.
9. Who proposed closed cycle approach?
a) Barjot
b) Alexander Edmond Becquerel
c) James Prescott joule
d) LA Rance
Answer: a
Explanation: The closed cycle approach was first proposed by Bajrot in 1926, but the most recent design was by Anderson in 1960s. The closed cycle is sometimes referred to as Anderson cycle. The Anderson cycle chose Propane as working fluid.
10. The working fluid chosen by Anderson OTEC cycle is ______
a) Propane
b) Water
c) Engine oil
d) ISO-butane
Answer: a
Explanation: The working fluid chosen by Anderson OTEC cycle is propane. The operating pressures of such fluid at the boiler condenser temperatures are much higher than those of water being roughly 10 bars at the boiler, and their specific volumes are much lower, being comparable to those of steam in conventional power plants.
11. Which is the working fluid in open cycle?
a) Propane
b) Water
c) Engine oil
d) ISO-butane
Answer: b
Explanation: In the open/Claude cycle, water is the working fluid. The warm water surface water is caused to boil by lowering the pressure, without supplying any additional heat. The low pressure steam produced then, drive’s the turbine and the exhaust steam is condensed by the deep colder water is discarded.
12. A continuous movement of water in specific direction is called as _________
a) float
b) waves
c) current
d) tides
Answer: d
Explanation: Water currents can be found in streams, rivers and oceans throughout the world. Water current is the rate of movement in the water, and ways to describe water current include its speed and direction. There are different types of water currents which behave in different ways because they are affected by separate variables.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Geothermal Energy”.
1. The process of producing energy by utilizing heat trapped inside the earth surface is called _________
a) Hydrothermal energy
b) Geo-Thermal energy
c) Solar energy
d) Wave energy
Answer: b
Explanation: The process of producing energy by utilizing heat trapped inside the earth surface is called Geo thermal energy. Energy present as heat in the earth’s crust. The more readily accessible heat in the upper most or so, of the crust constitutes a potentially useful and almost inexhaustible source of energy.
2. How much is the average temperature at depth of 10 km of earth surface?
a) 200 o C
b) 900 o C
c) 650 o C
d) 20 o C
Answer: a
Explanation: The heat is apparent from the increase in temperature of the earth with increasing depth below the surface. Although higher and lower temperature occurs, the average temperature at depth of 10 km is about 200 o C.
3. What is hot molten rock called?
a) Lava
b) Magma
c) Igneous rocks
d) Volcano
Answer: b
Explanation: Magma is a mixture of molten or semi-molten rock, volatiles and solid that is found beneath the surface of the Earth, and is expected to exist on other terrestrial planets and some natural satellites. Besides molten rock, magma may also contain suspended crystals, dissolved gas and sometimes gas bubbles.
4. How many kinds of Geo thermal steams are there?
a) 2
b) 3
c) 4
d) 5
Answer: a
Explanation: There are two kinds of geo thermal steams, the one that originates from the magma is called magmatic steam and that from ground water heated by magma is called meteoritic steam. The latter is the largest source of geothermal steam.
5. What does EGS stand for in geothermal energy?
a) Engraved Geothermal systems
b) Enhanced geothermal system
c) Exhaust gas system
d) Engineered geo physical system
Answer: b
Explanation: The development of a geothermal system where hydraulic fracturing of the system can allow the production at a commercial level. EGS’s are engineered reservoirs created where there is geothermal energy but a lack of permeability. Fluid is injected into the earth‘s surface which causes pre-existing fractures to open again, creating permeability. Nationwide potential with engineered reservoirs 6-km to 8-km deep.
6. Who invented first geothermal plant?
a) Michael Faraday
b) Piero Ginori Conti
c) Enrico Fermi
d) Guglielmo Marconi
Answer: b
Explanation: In 1904, Italian scientist Piero Ginori Conti invented the first geothermal electric power plant in which steam was used to generate the power. On 4 July 1904, at Larderello, Piero Ginori Conti powered five bulbs from a dynamo driven by a reciprocating steam engine using geothermal energy.
7. A geothermal solution containing appreciable amounts of sodium chloride or other salts is called as __________
a) Fluids
b) Brine
c) Solvent
d) Magma
Answer: b
Explanation: Brine is a high-concentration solution of salt in water. In different contexts, brine may refer to salt solutions ranging from about 3.5% up to about 26% .
8. Earth’s outer layer rock is called as __________
a) Mantle
b) Crust
c) Outer core
d) Asthenosphere
Answer: b
Explanation: Earth’s crust is Earth’s hard outer layer. It is less than 1% of Earth’s volume. The crust is made up of different types of rocks: igneous, metamorphic, and sedimentary rocks. Crust is also called as lithosphere.
9. The hole on earth’s surface from where the steam from the earth comes out is called as ________
a) Gash
b) Mud pot
c) Void
d) Fumarole
Answer: d
Explanation: A fumarole is an opening in a planet’s crust, often in areas surrounding volcanoes, which emits steam and gases such as carbon dioxide, sulfur dioxide, hydrogen chloride, and hydrogen sulfide. The steam forms when superheated water condenses as its pressure drops when it emerges from the ground.
10. A spring that shoots jets of hot water and steam into the air is called as _______
a) Mine hole
b) Geyser
c) Hot spring
d) Mud pot
Answer: b
Explanation: Geysers are temporary geological features. Geysers are generally associated with volcanic areas. As the water boils, the resulting pressure forces a superheated column of steam and water to the surface through the geyser’s internal plumbing.
11. Which kind geothermal plant is most common type?
a) Dry steam
b) Flash
c) Binary
d) Wet steam
Answer: b
Explanation: Flash Steam Power Plants are the most common form of geothermal power plant. The hot water is pumped under great pressure to the surface. When it reaches the surface the pressure is reduced and as a result some of the water changes to steam. This produces a ‘blast’ of steam. The cooled water is returned to the reservoir to be heated by geothermal rocks again.
12. How much is the efficiency of geothermal plant?
a) 28%
b) 15%
c) 42%
d) 30%
Answer: b
Explanation: Geothermal power plants have lower efficiency relative to other thermal power plants, such as coal, natural gas, oil, and nuclear power stations. It is commonly assumed that only 15% of the energy from the produced geothermal fluid can be converted to electricity.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Hydrothermal Systems”.
1. What is range of temperature at Hydro thermal reservoirs?
a) 350 o C
b) 210 o C
c) 50 o C
d) 1900 o C
Answer: a
Explanation: Hydrothermal resources are wet reservoirs at moderate depths containing steam and hot water under pressure at temperatures upto about 350 o C. These systems are further subdivided depending upon whether steam or hot water is dominant product.
2. When do hydrothermal resources arise?
a) When the movement of tectonic plates occurs
b) When the area is prone to volcanic eruptions
c) When water has access to high temperature
d) When temperature on earth surface is very high
Answer: c
Explanation: Hydrothermal resources arise when water has access to high temperature rocks, this account for the description as HYDROTHERMAL. The heat is transported from the hot rocks by circulating movement.
3. How does the hot water or steam escape through earth surface?
a) Through fissures
b) Through Pot holes
c) From Wells
d) Through water bodies
Answer: a
Explanation: Hot water or steam often escapes through fissures in the rock, thus forming hot springs, geysers fumaroles etc. in order to utilize the hydrothermal energy, wells are drilled either to intercept a fissure or more commonly into the formation containing the water.
4. What is the range of depth of most Hydro thermal wells?
a) 600 – 2100m
b) 50 – 60 m
c) 8 – 10 km
d) 1200 – 5400m
Answer: a
Explanation: Most hydrothermal wells range in the depth from about 600 to 2100 m, although there are some shallower and deeper production wells. As already mentioned for practical purposes hydrothermal resources are further subdivided into vapor dominated and liquid dominated types.
5. How the steam after passing turbine is cooled down in the geo thermal energy plant?
a) Water cooled
b) Cooling towers
c) Air cooled
d) Chemically cooled
Answer: b
Explanation: A direct system is used at the geysers in which the turbine exhaust steam is condensed by direct contact with cooling water. The resulting warm water is circulated through a mechanical draft cooling tower and returned to the condenser.
6. How much percent of Non-condensable gases are contained in steam?
a) 0.5 – 5%
b) 10 – 25%
c) 75 – 85%
d) 50%
Answer: a
Explanation: The steam contains 0.5 – 5% by weight of non-condensable gases which appear in the turbine exhaust. These gases consist mainly of carbon dioxide with small amounts of methane and ammonia, which are largely harmless in the quantities present.
7. The withdrawal of large amounts of steam from a hydrothermal reservoir may result in ____________
a) landslides
b) surface subsidence
c) light surface
d) loss of land fertility
Answer: b
Explanation: The withdrawal of large amounts of steam from a hydrothermal reservoir may result in surface subsidence. Such subsidences have sometimes occurred in oil fields and are dealt with injecting water into the ground.
8. What is the range of range of the water, which comes from degrees of salinity?
a) 300 – 8000 ppm
b) 4500 – 50,000 ppm
c) 70000 – 85000 ppm
d) 3000 – 280,000 ppm
Answer: d
Explanation: The water comes with various degrees of salinity, ranging from 3000 to 280,000 ppm of dissolved solids, and at various temperatures. There are, therefore, various systems for converting liquid dominated system into useful work that depend upon these variables.
9. Which among the following systems is used for water in high temperature range?
a) Vapor dominated systems
b) Flashed steam system
c) Liquid dominated total flow concept
d) Petro thermal systems
Answer: b
Explanation: Flashed steam system is used for water in the higher temperature range. Flash steam is low-pressure steam created when hot water is released from a high pressure to a lower pressure within a steam system.
10. Which geothermal systems are composed of hot dry rock but no underground water?
a) Hybrid geothermal Fossil system
b) Flashed steam system
c) Liquid dominated total flow concept
d) Petro thermal systems
Answer: d
Explanation: Petro thermal systems are composed of hot dry rock but no underground water. They are largest geothermal resource available. The rock occurring at moderate depths has very low permeability and needs to be increasing its heat transfer surface.
11. Which geothermal system utilizes relatively low temperature heat of geothermal sources?
a) Hybrid geothermal Fossil system
b) Flashed steam system
c) Liquid dominated total flow concept
d) Petro thermal systems
Answer: a
Explanation: The hybrid geothermal fossil fuel systems utilizes the relatively low temperature heat of geothermal sources in the low temperature end of a conventional cycle and the high temperature heat from fossil fuel combustion in the high temperature cycle with a natural source of heat for part of heat addition, thus reducing the consumption if the expensive and non renewable fossil fuels.
12. How many possible arrangements are there for Hybrid geothermal plants?
a) 2
b) 3
c) 4
d) 5
Answer: a
Explanation: There are two possible arrangements for hybrid plants. These are geothermal preheat suitable for low temperature liquid dominated systems, and fossil superheat, suitable for vapor dominated and high temperature liquid dominated systems.
This set of Energy Engineering Assessment Questions and Answers focuses on “Problems Associated with Geothermal Conversion”.
1. How are solids present in steam and water of geothermal energy removed?
a) Flocculation
b) De-sanding Hydro clones
c) Centrifugal separators
d) Gravity setting
Answer: c
Explanation: Steam and water from both hydrothermal systems contain along with the dissolved solids in the water, entrained solid particles and non-condensable gases. The entrained solids must be removed as much as possible, usually by centrifugal separators at the well head, before they enter plant equipment and strainers.
2. How do Non-condensable gases escape from geothermal plant?
a) Air vents
b) Trap holes
c) Condenser ejectors
d) Centrifugal Filters
Answer: c
Explanation: The non condensable gas content varies from 0.2 – 0.4 percent depending upon the particular well and its age. The non condensable themselves are mostly CO 2 plus varying amount of methane CH 4 , hydrogen H 2 , nitrogen, ammonia and hydrogen sulfide. Besides finding way with the fluid into the plant equipment the non condensable partly escape to atmosphere via condenser ejectors.
3. Non condensable are environmentally undesirable because __________
a) tare not soluble
b) they contain Solid particles
c) they partly escape into atmosphere
d) they damage the machineries
Answer: c
Explanation: Non condensable are environmentally undesirable because they partly escape into the atmosphere. Most are corrosive in the normal damp atmosphere of the plant and are noxious and toxic and hence major pollutants.
4. Which is the environmental problem caused by geothermal energy?
a) Landslide
b) Loose soil
c) Land surface subsidence
d) Loss of fertility of land
Answer: c
Explanation: Environmental problem caused by geothermal plants is land surface subsidence because of the extraction of large quantities of underground fluids. Large extractions and re-injections also pose possibility of seismic disturbances.
5. What is the material used for building turbines in geothermal plant?
a) Chrome steel
b) Bronze alloys
c) Cast iron
d) Copper alloys
Answer: a
Explanation: In the turbine, steam nozzles and blades are subjected to dry or high quality steam is usually made of 11 to 13 percent chrome steel. The nozzles are usually designed with large throat areas o a wide pitch to minimize scaling.
6. Which material is recommended for condensate pipes?
a) Cast iron
b) Aluminum
c) Copper
d) Steel
Answer: b
Explanation: Aluminum is recommended for condensate pipes and valves that are made large enough to allow low velocities and hence erosion. Aluminum is also recommended for switchyard structures that are in the open but in a generally corrosive atmosphere.
7. Which gas is always present in geothermal fields?
a) CO 2
b) H 2 S
c) N 2 O
d) H 2 O
Answer: b
Explanation: H 2 S is always present in geothermal field. If this gas is present in excess quantities may cause harmful effects on the bearings. This also attacks electrical equipments and it may have adverse effects on corps and on river life.
8. Which process could avoid discharging large quantities into the river?
a) Filtration
b) Centrifuge distillation
c) Re-injection
d) Condensation
Answer: c
Explanation: Re-injection could avoid discharging large quantities of heat into rivers, with consequent hazards to fisheries, and would also avoid infecting rivers and stream with toxic substances emitted from the bores which would endanger downstream with toxic substances, water supplies and farming activities.
9. Which among the following is problem caused by geothermal plant?
a) Land usage
b) Noise pollution
c) Global warming
d) Greenhouse effect
Answer: b
Explanation: Noise pollution is another problem. Exhausts, blow downs and centrifugal separation are some sources off noise pollution that necessitate the installation of silencers on some equipment. The noise causes a serious health hazards.
10. Which of the following can affect the fisheries in river?
a) Heat pollution
b) Noise pollution
c) Land erosion
d) Air borne poisons
Answer: a
Explanation: Heat pollution in river water can damage fisheries and encourage growth of unwanted water weeds. Possible remedies include re-injection of surplus cooling tower water and unwanted bore water, the generation of additional power by means of binary fluid cycles etc.
11. Does harnessing of geothermal energy cause earthquakes.
a) True
b) False
Answer: a
Explanation: Some fears have been expressed that prolonged geothermal exploitation could trigger off earth quakes especially if reinjection is practiced in zones of higher shear stresses where fairly large temperature differentiation occurs.
12. How many known geothermal areas are there in India?
a) 200
b) 340
c) 147
d) 60
Answer: b
Explanation: There are about 340 known geothermal areas in India, each represented by hot or warm springs. Many more areas are being discovered and reported, in the 12 well defined geothermal provinces.
This set of Basic Energy Engineering Questions and Answers focuses on “Energy from Biomass”.
1. Which is an organic matter produced by plants in direct or indirect forms?
a) Solar energy
b) Biomass
c) Wind energy
d) Bio-fuel
Answer: b
Explanation: Biomass is an organic matte produced by plants in direct or indirect forms. Energy from biomass has got very large potential which can substitute the conventional energy sources. Biomass with conversion systems can be used for variety of applications including power generation.
2. What type of energy is biomass energy?
a) Conventional energy
b) Non renewable
c) Commercial energy
d) Sustainable energy
Answer: d
Explanation: Biogas is renewable energy source. Biomass energy from plants and plant derived materials. Wood is still the largest biomass energy resource today, but other sources of biomass can also be used.
3. The use of biomass energy has the potential to greatly reduce greenhouse gas emissions.
a) True
b) False
Answer: a
Explanation: The use of biomass energy has the potential to greatly reduce greenhouse gas emissions. Burning biomass releases about the same amount of carbon dioxide as burning fossil fuels. However, fossil fuels release carbon dioxide captured by photosynthesis millions of years ago an essentially “new” greenhouse gas.
4. __________ is made by combining alcohol with vegetable oil, animal fat or recycled cooking grease.
a) Biodiesel
b) Biomass
c) Bioelectricity
d) Syngas
Answer: a
Explanation: Biodiesel is made by combining alcohol with vegetable oil, animal fat or recycled cooking grease. It can be used as an additive to reduce vehicle emissions or in its pure form as a renewable alternative fuel for diesel engines.
5. What type of fire system is used in Bio power?
a) Hand firing
b) Mechanical stoke firing
c) Direct firing
d) Indirect firing
Answer: c
Explanation: Most of the bio power plants are direct fired systems. They burn bio energy feed stocks directly to produce steam. This steam drives a turbine, which in turns a generator that converts the power into electricity.
6. Mixing biomass with fossil fuels in conventional power plants is referred to as ___________
a) Agitation
b) Infuse
c) Co-firing
d) Interbreed
Answer: c
Explanation: Co-firing refers to mixing biomass with fossil fuels in conventional power plants. Coal fired power plants can use co-firing systems to significantly reduce emissions, especially sulfur dioxide emissions.
7. Which gas can be chemically converted into other fuels or products, burned in a conventional boiler, or used instead of natural gas in gas turbine?
a) Freon
b) Natural gas
c) Syngas
d) Noble gas
Answer: c
Explanation: The synthesis gas or Syngas can be chemically converted into other fuels or products, burned in a conventional boiler, or used instead of natural gas in gas turbine. Gas turbines are very much like jet engines, only they turn electric generators instead of propelling a jet.
8. What does natural decay of biomass produces?
a) Ozone
b) Methane
c) Ethane
d) Hydrogen
Answer: b
Explanation: The natural decay of biomass produces methane, which can be captures and used for power production. In landfills, wells can be drilled to release the methane from decaying organic matter. Then pipes from each well’s carry the methane to a central point, where it is filtered and cleaned before burning.
9. What is used to decompose organic matter in absence of oxygen in closed reactors?
a) Slugs
b) Fungi
c) Natural consortia
d) Methane
Answer: c
Explanation: Methane can also be produced from biomass through a process called anaerobic digestion. Natural consortia of bacteria are used to decompose organic matter in the absence of oxygen in closed reactors.
10. What is Ethanol called?
a) Phenol
b) Alcohol
c) Amino acid
d) Butanol
Answer: b
Explanation: Ethanol is also called as an alcohol. In biomass, it is made by fermenting any biomass high in carbohydrates through a process similar to beer brewing. Ethanol is also made from starches and sugars.
11. Which type of bio products include Antifreeze, plastics, glues, artificial sweeteners, and gel for toothpaste?
a) Bio products made from sugars
b) Bio products made by waste products
c) Bio products made from decomposition
d) Bio products made from catalytic cracking
Answer: a
Explanation: Bio products that can be made from sugars include antifreeze, plastics, glues, artificial sweeteners, and gel for toothpaste. Bio products that can be made from carbon monoxide and hydrogen of Syngas include plastics and acids, which can be used to make photographic films, textiles, and synthetic fabrics.
12. What is BTU used to measure?
a) Heat content
b) Area
c) Density
d) Volume
Answer: a
Explanation: The British thermal unit is a traditional unit of heat; it is defined as the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit. Its counterpart in the metric system is the calorie, which is defined as the amount of heat required to raise the temperature of one gram of water by one degree Celsius.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Photosynthesis”.
1. The process by which plants, some bacteria and some protistans use the energy from sunlight to produce sugar?
a) Taxonomy
b) Metabolism
c) Photosynthesis
d) Osmosis
Answer: c
Explanation: Photosynthesis is the process, by which plants, some bacteria and some protistans use the energy from sunlight to produce sugar, which cellular respiration converts into ATP, the fuel used by all living things.
2. What is used in conversion of sunlight energy into usable chemical energy in plants?
a) Anthocyanin
b) Cythochrome
c) Chlorophyll
d) Chitin
Answer: c
Explanation: The conversion of usable sunlight energy into usable chemical energy is associated with the actions of the green pigment chlorophyll. Most of the time, photosynthetic process use water and releases the oxygen that we absolutely must have to stay alive.
3. Complete the following reaction.
H 2 O + CO 2 → ________
a) 6H 2 O + 6CO 2 → C 6 H 12 O 6 + 6O 2
b) 6H 2 O + 3CO 2 → C 6 H 6 O 6 + 4O 2
c) 6H 2 O + 6CO 2 → C 6 H 12 O 12 + 12O 2
d) 6H 2 O + 4CO 2 → C+ HO 3
Answer: a
Explanation: 6H 2 O + 6CO 2 → C 6 H 12 O 6 + 6O 2 is the proper form of equation.
Six molecules of water + six molecules of carbon dioxide &raar; one molecule of sugar + six molecules of oxygen.
4. Photosynthesis is carried in how many stages?
a) 1
b) 2
c) 3
d) 4
Answer: b
Explanation: Photosynthesis is a two stage process. The first process is light dependent process which requires the direct energy of light to make energy carrier molecules that are used in the second process. And the second stage is termed as Dark reaction.
5. Photosynthetic organisms which convert light energy into the chemical energy they need to develop grow, and reproduce are called as?
a) Rubisco
b) Pigment
c) Autotrophs
d) Glucose
Answer: c
Explanation: An autotroph or producer, is an organism that produces complex organic compounds from simple substances present in its surroundings, generally using energy from light or inorganic chemical reactions.
6. What is the full form of ATP?
a) Adenosine Tetra-phosphate
b) Adenosine tri-phosphate
c) Adenosine Terra-phosphate
d) Ambient temperature and pressure
Answer: b
Explanation: Adenosine tri-phosphate is a complex organic chemical that participates in many processes. Found in all forms of life, ATP is often referred to as the “molecular unit of currency” of intracellular energy transfer.
7. What does NADPH?
a) Nicotinamide adenosine deca-nucleotide phosphate
b) Nicotinamide adenine dinucleotide phosphate
c) Nicotinamide adenine deca-nucleotide phosphate
d) Nicotinamide adenosine dinucleo phosphor
Answer: b
Explanation: In photosynthetic organisms, NADPH is produced by ferredoxin-NADP+ reeducates in the last step of the electron chain of the light reactions of photosynthesis. It is used as reducing power for the biosynthetic reactions in the Calvin cycle to assimilate carbon dioxide.
8. Which cycle is preferred for production of carbohydrates?
a) Nutrient cycle
b) Bio geo chemical cycle
c) Calvin – Benson Cycle
d) Sonnet cycle
Answer: c
Explanation: The Calvin cycle is the set of chemical reactions that take place in chloroplasts during photosynthesis. The cycle is light-independent because it takes place after the energy has been captured from sunlight. This cycle is used for the production of carbohydrate.
9. Which is the region within thylakoid where water is split into oxygen?
a) Foramen
b) Serosa
c) Lumen
d) Mucosa
Answer: c
Explanation: The lumen is the region within the thylakoid membrane where water is split to obtain oxygen. The oxygen diffuses out of the cell, while the protons remain inside to build positive electrical charge inside the thylakoid.
10. Choose the general formula of carbohydrates?
a) [C 2 H 2 O 2 ] n
b) [CHO] n
c) [CH 2 O] n
d) [C 2 O 2 ] n
Answer: c
Explanation: [CH 2 O] n is the correct form for representing carbohydrates. Green plants make food in the form of carbohydrates by combining carbon dioxide and water using energy from sunlight. The simplest useful form of carbohydrate produced by photosynthesis is glucose sugar. Glucose may be used as an energy source.
11. Energy plantation does not have any impact on Bio-energy.
a) True
b) False
Answer: b
Explanation: Energy plantation means growing select species of trees and shrubs which are harvestable in a comparably shorter time and are specifically meant for fuel. The fuel wood may be used either directly in wood burning stoves and boilers or processed into methanol, ethanol and producer gas.
12.”ATP and NADPH are used to fix CO 2 into carbohydrates” this process is termed as ________
a) Carbon fixation
b) Reduction
c) Carbon dating
d) Oxidation
Answer: a
Explanation: Carbon fixation or Carbon assimilation is the conversion process of inorganic carbon to organic compounds by living organisms. The most prominent example is photosynthesis, although chemosynthesis is another form of carbon fixation that can take place in the absence of sunlight.
13. The organelle in a plant cell where photosynthesis occurs is called _________
a) Rubisco
b) Chloroplast
c) Thylakoid
d) Pigment
Answer: b
Explanation: The main role of chloroplasts is to conduct photosynthesis, where the photosynthetic pigment chlorophyll captures the energy from sunlight and converts it and stores it in the energy-storage molecules ATP and NADPH while freeing oxygen from water.
14. A colored molecule is called ________
a) Epoxy
b) Pigment
c) Gouache
d) Plaster
Answer: b
Explanation: Chlorophyll-‘a’ is the primary pigment for photosynthesis in plants, but the range of light absorption is extended by chlorophyll-‘b’, beta-carotene and other accessory pigments. These are present inside a chloroplast.
15. C 6 H 12 O 6 is a _________
a) Osmophile
b) Trapiche
c) Sugar
d) Butanol fuel
Answer: c
Explanation: Glucose is a simple sugar with the molecular formula C 6 H 12 O 6 , which means that it is a molecule that is made of six carbon atoms, twelve hydrogen atoms, and six oxygen atoms. Plants form sugar on photosynthesis.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Anaerobic Fermentation – 1”.
1. How many types of basic organic decomposition occur in Biomass energy conversion?
a) 2
b) 3
c) 4
d) 5
Answer: a
Explanation: There are two basic types of organic decomposition that can occur: aerobic decomposition and anaerobic decomposition . All organic material, both animal and vegetable can be broken down by these processes.
2. Which decomposition process produces carbon dioxide and ammonia?
a) Aerobic decomposition
b) Anaerobic decomposition
c) Thermolysis
d) Thermal decomposition
Answer: a
Explanation: Aerobic decomposition process produces carbon dioxide, ammonia and other small amounts of gases, heat in large quantities and a final product that can be used as a fertilizer. Aerobic decomposition is process of decomposition in presence of oxygen.
3. Which decomposition process produces Carbon dioxide and methane?
a) Aerobic decomposition
b) Anaerobic decomposition
c) Thermolysis
d) Thermal decomposition
Answer: b
Explanation: Anaerobic decomposition will produce methane, carbon dioxide, some hydrogen and other gases in trace, very little heat and a final product with a higher nitrogen content than is produced by anaerobic fermentation process.
4. Anaerobic fermentation is how many staged process?
a) Single stage
b) Two – stage
c) 3-stage
d) 4 – stage
Answer: b
Explanation: Anaerobic decomposition is a two stage process as specific bacteria feed on certain organic materials. In the first stage, acidic bacteria dismantle the complex organic molecules into peptides, glycerol, alcohol and other sugars. Than the second type of bacteria starts to convert these simpler compounds into methane.
5. In what PH range does anaerobic digestion occurs at best?
a) 6.8 – 8.0
b) 0 – 5.0
c) 2.3 – 4.5
d) 3.5 – 7.2
Answer: a
Explanation: Anaerobic digestion will occur best within a PH range of 6.8 – 8.0. More acidic or basic mixtures will ferment at a lower speed. The introduction of raw material will often lower the PH .
6. Which amount is the ideal carbon-nitrogen ratio for the raw material into a biogas plant?
a) 30: 1
b) 20: 10
c) 5: 15
d) 1: 8
Answer: a
Explanation: The bacteria responsible for anaerobic process require both elements, as do all living organisms, but they consume carbon roughly 30 times faster than nitrogen. Assuming all other conditions are favorable for biogas production, a carbon – nitrogen ratio of about 30: 1 is ideal for the raw material fed into a biogas plant.
7. Below which temperature the action off digesting bacteria decreases?
a) 16 o C
b) 35 o C
c) 28 o C
d) 0 o C
Answer: a
Explanation: Anaerobic breakdown of waste occurs at temperatures lying between 0 o C and 69 o C, but the action of digesting bacteria will decrease sharply below 16°C. Production of gas is most rapid between 29 o C and 41 o C.
8. Which is the most suitable temperature for the production of methane in anaerobic fermentation?
a) 32 – 35 o C
b) 18 – 26 o C
c) 40 – 48 o C
d) 10 – 15 o C
Answer: a
Explanation: A temperature between 32 – 35 o C has proven most efficient for stable and continuous production of methane. Biogas produced outside this range will have a higher percentage of carbon dioxide and other gases than within this range.
9. Too nitrogen will cause ____________
a) Poisonous gases
b) Reduction in fertility of mixture
c) Reduction in quantity of mixture
d) Mixture to harden
Answer: b
Explanation: Too much nitrogen will cause this to be left over at the end of digestion and reduce the quality of the fertilizer produced by biogas plant. The correct ratio of carbon to nitrogen will prevent loss of either fertilizer quality or methane content.
10. How much percentage of solid content is present in anaerobic digestion?
a) 8%
b) 2%
c) 32%
d) 50%
Answer: a
Explanation: Anaerobic digestion of organics will proceed best if the input material consists of roughly 8% solids. In the case of fresh cow manure, this is the equivalent of dilution with roughly an equal quantity of water.
11. The central part of an anaerobic plant in an enclosed tank is known as ____________
a) Pit
b) Digester
c) Mixer
d) Feeder
Answer: b
Explanation: The central part of an anaerobic plant in an enclosed tank is known as digester. This is an airtight filled with the organic waste, and which can be emptied of digested slurry with some means of catching the produced gas.
12. What is ADP stand for?
a) Adenosine terra phosphate
b) NADPH
c) Adenosine pyrophosphate
d) Adenosine tri-phosphate
Answer: c
Explanation: Adenosine di-phosphate , also known as adenosine pyrophosphate , is an important organic compound in metabolism and is essential to the flow of energy in living cells. ADP consists of three important structural components: a sugar backbone attached to adenine and two phosphate groups bonded to the 5 carbon atom of ribose.
13. What is C 3 H 7 O 6 P?
a) Glyceraldehydes’ 3-phosphate
b) 3-bisphosphoglycerate
c) NADPH
d) Tryptophan
Answer: a
Explanation: Glyceraldehydes’ 3-phosphate, also known as trio-phosphate and abbreviated as G3P, GALP or PGAL, is a chemical compound that occurs as an intermediate in several central metabolic pathways of all organisms. It is a phosphate ester of the 3-carbon sugar glyceraldehydes and has chemical formula C 3 H 7 O 6 P.
14. Product of anaerobic decomposition involves ___________
a) Methane
b) Lactic acid
c) Oxygen
d) Alcohol
Answer: a
Explanation: A second type of bacteria in secondary stage of anaerobic fermentation starts to form methane. These methane producing bacteria are particularly influenced by the ambient conditions, which can slow or halt the process completely if they do not lie within a fairly narrow band.
15. Solid remnants of the original input material to the digesters are called ________
a) Ordure
b) Egests
c) Digestate
d) Manure
Answer: c
Explanation: Digestate is the solid remnants of the original input material to the digesters that the microbes cannot use. It also consists of the mineralized remains of the dead bacteria from within the digesters. Digestate can come in three forms: fibrous, liquor, or a sludge-based combination of the two fractions.
This set of Tricky Energy Engineering Questions and Answers focuses on “Anaerobic Fermentation – 2”.
1. How are systems intended for the digestions are filled and emptied?
a) Manually
b) By evaporation
c) By pumps and pipes
d) By channels and pits
Answer: c
Explanation: Systems intended for the digestion of liquid or suspended solid waste are mostly filled or emptied using pumps and pipe work. A simple version is simply to gravity feed the tank allow the digested slurry to overflow the tank.
2. Cow manure is rich in __________
a) Hydrogen
b) Phosphorus
c) Nitrogen
d) Potassium
Answer: c
Explanation: Cow dung is the undigested residue of plant matter which has passed through the animal’s gut. The resultant fecal matter is rich in minerals. Color ranges from greenish to blackish, often darkening soon after exposure to air. And it is very rich in nitrogen.
3. How many weeks does complete digestion of cow manure takes about?
a) 1
b) 2
c) 4
d) 8
Answer: d
Explanation: The complete anaerobic digestion of cow manure takes about 8 weeks at normally warm temperatures. One third of the total biogas will be produced in the first week, another quarter in the second week and the remainder of the biogas production will be spread over the remaining 6 weeks.
4. How many weeks does a batch digester need to produce biogas?
a) 1 week
b) 2 – 4 week
c) 12 week
d) 4 – 8 week
Answer: b
Explanation: Depending on the waste material and operating temperature, a batch digester will start producing biogas after 2 – 4 weeks, slowly increase in production then drop off after three or 4 months. Batch digesters are therefore best operated in groups.
5. Which of the following matter has a much higher carbon – nitrogen ratio?
a) Vegetable matter
b) Cow dung
c) Plant waste
d) Organic waste from industry
Answer: a
Explanation: Most vegetable matte has a much higher carbon – nitrogen ratio than dung has, so some nitrogen producers must generally be added to vegetable matter, especially when batch digestion is used.
6. Which of the following waste produces more gases comparatively?
a) Vegetable matter
b) Cow dung
c) Plant waste
d) Organic waste from industry
Answer: a
Explanation: Vegetable matter produces about 8 times more gas, so the quantity required is much smaller in batch production for the same gas production from any other wastes. A mixture of dung and vegetable matter is hence ideal in most ways, with a majority of vegetable matter to provide the biogas and the valuable methane contained in it.
7. How much thick layer of insulation is done inside of digester?
a) 10 cm
b) 15 – 25 mm
c) 8 mm
d) 50 – 100 cm
Answer: d
Explanation: In hot regions it is relatively easy to simply shade the digester to keep it in the ideal range of temperature, but cold climates present more of a challenge. The first action is, naturally, to insulate the digester with straw or wood shavings. A layer about 50 – 100 cm thick, coated with a waterproof covering is a good start.
8. What happens if the organic matter is not stirred while in process of digestion?
a) It will evaporate
b) It solidifies
c) It will form hard scum on layer
d) It gets struck to digester walls
Answer: c
Explanation: Some method of stirring the slurry in a digester is always advantageous, if not essential. If not stirred, the slurry will tend to settle out and form a hard scum on the surface, which will prevent release of biogas.
9. How is biogas from an anaerobic digester collected?
a) In a compressor
b) In the pipelines
c) In inverted drum
d) In a storage tank
Answer: c
Explanation: The biogas in an anaerobic digester is collected in an inverted drum. The walls of the drum extended down into the slurry to provide a seal. The drum is free to move to accommodate more or less gas needed.
10. Which type of valve is used to prevent air being drawn into the digester?
a) Non return valve
b) Poppet vale
c) Return valve
d) Check valve
Answer: a
Explanation: A non return valve is a valuable investment to prevent air being drawn into digester, which would destroy the activity of bacteria and provided a potentially explosive mixture inside the drum. Larger plants may need counterweights of some sort to ensure that the explosive mixture inside the drum.
11. Which types of plants are filled and then emptied completely after fixed retention time?
a) Batch plants
b) Continuous plants
c) Floating gas holder plants
d) Flexible bag biogas plant
Answer: a
Explanation: Batch plants are filled and then emptied completely after a fixed retention time. Each design and each fermentation material is suitable for batch filling, but batch plants require high labor input.
12. What is the major disadvantage of batch plants?
a) Their output is not steady
b) Comes to frequent breakdown
c) They are not efficient
d) They are very costly
Answer: a
Explanation: Batch biogas plants are loaded with substrate completely and after some determined digestion time are fully unloaded. For this loading method any design of biogas plant and any design of biogas plant any substrate can be used, but such plants are distinguished by unstable biogas production. The major disadvantage of batch plant is the output is not steady.
13. Which among the following best suitable treatment of waste products?
a) Aerobic fermentation
b) Anaerobic fermentation
c) Autolysis
d) Thermal reaction
Answer: b
Explanation: Anaerobic process is especially considered as a suitable treatment option due to low-energy requirements and little quantities of sludge production. Therefore, anaerobic process has become increasingly demanding in the treatment of complex industrial wastes.
14. What does PSD stand for?
a) Post source decay
b) Particle size distribution
c) Polystyrene deuterated
d) Post synaptic density
Answer: b
Explanation: The particle-size distribution of a powder, granular material, or particles dispersed in fluid is a list of values or a mathematical function that defines the relative amount, typically by mass, of particles present according to size.
15. Which is the third stage of anaerobic digestion?
a) Acetogenesis
b) Methanogenesis
c) Acidogenesis
d) Hydrolysis
Answer: a
Explanation: The third stage of anaerobic digestion is acetogenesis. Here, simple molecules created through the acidogenesis phase are further digested by acetogens to produce largely acetic acid, as well as carbon dioxide and hydrogen.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Types of Biogas Plants – 1”.
1. Which types of plant are fed and emptied regularly?
a) Batch type plants
b) Continuous type plants
c) Dome type plants
d) Drum type plants
Answer: b
Explanation: Continuous plants are fed and emptied continuously. They empty automatically through the overflow whenever new material is filled in. therefore, the substance must be fluid and homogeneous.
2. Gas production of continuous plant is higher than which of the following plant?
a) Batch plant
b) Dome plant
c) Drum plant
d) Flexible gas biogas plant
Answer: a
Explanation: Continuous plants are suitable for rural households as the necessary work fits well into daily routine. Gas production is constant and higher than in batch plants. Today, nearly all biogas plants are operating on a continuous mode.
3. What type of plant is a floating gas holder plant?
a) Batch plant
b) Continuous plant
c) Semi-batch plant
d) Semi-continuous plant
Answer: d
Explanation: This is one of the common designs in India, coming under category of semi-continuous feed plant. It has a cylindrical floating biogas holder on top of the well shaped digester. This digester is vividly used in rural sides.
4. For how much percent is biogas normally designed to hold?
a) 35%
b) 20%
c) 50%
d) 80%
Answer: c
Explanation: As the biogas is produced in the digester, it rises vertically and gets accumulated and stored in the biogas holder at a constant pressure of 8-10 cm of water column. The biogas holder is normally designed to store 50% of the daily gas production.
5. Where was fixed dome concept plant developed?
a) China
b) America
c) India
d) Japan
Answer: c
Explanation: The plant based on fixed dome concept was developed in India in the middle 1970s. The Chinese fixed plants use a seasonal crop wastes as the major feed stock for feeding, therefore, their design is based on principle of semi-batch-feed digester.
6. Indian fixed dome digesters are designed for holding what pressure capacity?
a) 0 – 90 cm of water column
b) 70 – 90 cm of water column
c) 50 – 65 cm of water column
d) 10 – 25 cm of water column
Answer: a
Explanation: The Indian fixed dome plant design use the principle of displacement of slurry inside the digester for storage of biogas in the fixed gas storage chamber. Indian fixed dome biogas digesters are designed for pressure inside the plant varying from 0 to 90 cm of water column.
7. Fixed dome biogas plant is best suitable for which type of plant?
a) Continuous type
b) Batch type
c) Semi-batch type
d) Semi continuous type
Answer: b
Explanation: The discharge opening is located on water wall surface of the outlet displacement chamber and it spontaneously controls the maximum pressure. It is best suited for batch process especially when daily feeding is adopted in small quantities.
8. Which plants digester is fabricated by using rubber?
a) Flexible Bag biogas plant
b) Fixed dome biogas plant
c) Floating drum biogas plant
d) Khadi and village industries type biogas plant
Answer: a
Explanation: Main unit of the plant including the digester is fabricated by using rubber, high strength plastic, neoprene or red mud plastic. The inlet and outlet are made of heavy duty PVC tube. A small pipe of same PVC tube is fixed on top of the plant as gas outlet pipe.
9. Which type of plant is portable?
a) Flexible Bag biogas plant
b) Fixed dome biogas plant
c) Floating drum biogas plant
d) Khadi and village industries type biogas plant
Answer: a
Explanation: Flexible bag biogas plant is portable and can easily be erected. It requires support from outside, upto the slurry level, to maintain the shape as per its design configuration, which is done by placing the bag inside a pit dug on site.
10. In which type of plant the weight needs to be added on top to build the desired pressure?
a) Flexible Bag biogas plant
b) Fixed dome biogas plant
c) Floating drum biogas plant
d) Khadi and village industries type biogas plant
Answer: a
Explanation: The depth of the pit should be in proportion to height of the digester so that the mark of initial slurry level is in line with the ground level. The outlet pipe is fixed in such a way that its outlet opening is also in line with the ground level. Some weight has to be added on the top of the bag to build the desired pressure to convey the generated gas to the point of utilization.
11. What is the main advantage of flexible bag plant?
a) The fabrication can be centralized for mass production
b) It has highest gas storage capacity
c) It is portable from place to place
d) Easy to understand and work on it
Answer: a
Explanation: Advantage of flexible bag plant is that the fabrication can be centralized for mass production. Individuals or agencies having land and basic infrastructure can take up fabrication of the biogas plant with small investment.
12. Khadi village industries type biogas plant is example of _________
a) flexible Bag biogas plant
b) fixed dome biogas plant
c) floating drum biogas plant
d) semi-batch type
Answer: c
Explanation: Khadi and village industries type biogas plant is an example of Floating drum biogas plant. It is a semi continuous plant. It is one of the most common types of biogas plant used in rural area of India.
13. Vertical type KVIC is more commonly used than horizontal type.
a) True
b) False
Answer: a
Explanation: The KVIC model is a floating holder semi continuous fed bio gas plant and has two types, Vertical and Horizontal. The vertical type is more commonly used and the horizontal type is used only in the high water table region.
14. Which part of the KVIC is made of mixture of cement concrete and brick ballast?
a) Foundation
b) Digester
c) Gas holder
d) Inlet and outlet pipe
Answer: a
Explanation: Foundation of a KVIC is compact base made of a mixture of cement concrete and brick ballast. The foundation is well compacted using wooden ram and then top surface is cemented to prevent any percolation & seepage.
This set of Tough Energy Engineering Questions and Answers focuses on “Types of Biogas Plants – 2”.
1. The ____________ is made of bricks and cement mortar and it’s inside wall are plastered with a mixture of cement and sand.
a) Foundation
b) Digester
c) Gas holder
d) Inlet and outlet pipe
Answer: b
Explanation: Digester of KVIC is a cylindrical shaped well like structure, constructed using the foundation as its base. The digester is made of bricks and cement mortar and it inside walls are plastered with a mixture of cement and sand.
2. From what material is biogas holder drum made?
a) Mild steel
b) Cast iron
c) Aluminum alloys
d) Rot iron
Answer: a
Explanation: The biogas holder drum of KVIC model is normally made of mild steel sheets. The biogas holder rests on a ledge constructed inside the walls of the digester well. If the KVIC model is made with water jacket on top of the digester wall, no ledge is made and the drum of the biogas holder is placed inside the water jacket.
3. What is the weight of biogas holder?
a) 8-10 kg/m 2
b) 10-15 kg/m 2
c) 8-18 kg/m 2
d) 25-30 kg/m 2
Answer: a
Explanation: The weight of the biogas holder is 8-10 kg/m 2 . The biogas holder of KVIC is also fabricated out of fiber glass reinforced plastic , high density polyethylene or Ferroconcrete .
4. What type of movement does a biogas holder of KVIC has?
a) Linear Movement
b) Transverse movement
c) Rotary movement
d) Circular movement
Answer: c
Explanation: The biogas holder of a KVIC moves up and down on a guide pipe situated in the centre of the digester. The biogas holder has a rotary movement that helps in breaking the scum-mat formed on the top surface of the slurry. The weight of the biogas holder is 8-10 kg/m 2 . So that it can store biogas at a constant pressure of 8-10 cm of water column.
5. How is the inlet pipe of KVIC made?
a) Cement mortar
b) Asbestos cement concrete
c) White cement
d) PVC
Answer: b
Explanation: The inlet pipe is made out of cement concrete or Asbestos cement concrete or pipe. The one end of the inlet pipe is concrete to the mixing tank and the other end goes inside the digester on the inlet side of the partition wall and rests on a support made of bricks of about 1 feet height.
6. How is the outlet pipe of KVIC made?
a) Cement mortar
b) Asbestos cement concrete
c) White cement
d) PVC
Answer: b
Explanation: The outlet pipe is made out of cement concrete or asbestos cement concrete or pipe. The one end of the outlet pipe is connected to the outlet tank and the other end goes inside the digester, on the outlet side of the partition wall and rests on a support made of about bricks of about 1 feet height.
7. How is the Biogas outlet pipe of KVIC made?
a) Cement
b) PVC
c) Asbestos
d) GI pipe
Answer: d
Explanation: The biogas outlet pipe is fixed on the top middle portion of the biogas holder, which is made of a small of GI pipe fitted with socket and a gat valve. The biogas generated in the plant and stored in the biogas holder is taken through the gas outlet pipe via pipeline to the place of utilization.
8. What is the life time of Floating drum plant?
a) Short
b) Large
c) Life time
d) Average
Answer: a
Explanation: Even though the floating drum plant is built with all reinforced constituents and hard materials the life of floating drum plant is short which is upto 15 years; And in tropical coastal regions its just about 5 years.
9. Which plant has no movable parts?
a) KVIC
b) JANATA model
c) Pragati design plant
d) Ferro – cement plant
Answer: b
Explanation: The janata model consists of a digester and fixed biogas holder as gas storage chamber covered by a dome shaped enclosed roof structure. The entire plant is made of bricks and cement masonry and constructed underground. Unlike the KVIC, the janata model has no movable part.
10. Which part of the janata bio gas plant comprises of the fermentation chamber and the gas storage chamber?
a) Foundation
b) Digester
c) Inlet chamber
d) Outlet chamber
Answer: b
Explanation: The digester is a cylindrical tank resting on the foundation. The top surface of the foundation serves as the bottom of the digester. The digester of janata biogas plant comprises of the fermentation chamber and the gas storage chamber.
11. The Gas storage chamber of the digester of janata model is designed to store what percentage og daily gas?
a) 5%
b) 19%
c) 33%
d) 58%
Answer: c
Explanation: The gas storage chamber is also cylindrical in shape and is the integral part of the digester and located just above the fermentation chamber. The GSC is designed to store 33% of the daily gas production from the plant.
12. Which plant has fixed hemi-spherical roof?
a) Fixed dome plant
b) Floating drum plant
c) Chinese plant
d) Flexible bag biogas plant
Answer: a
Explanation: Fixed dome plant has a fixed hemi-spherical roof which forms the cover of the digester and constructed with brick and cement concrete mixture, after which it is plastered with cement mortar. The dome is only an enclosed roof designed in such a way to avoid steel reinforcement.
13. The upper portion of the ______________ is in the shape of bell mouth and constructed using bricks and cements mortar in fixed dome plant.
a) gas storage chamber
b) inlet chamber
c) outlet chamber
d) digester
Answer: b
Explanation: The upper portion of the inlet chamber is in the shape of bell mouth and constructed using bricks and cements mortar in fixed dome plant. It s outer wall is kept inclined to the cylindrical wall of the digester so that the feed material can flow easily into the digester by gravity.
14. The outer chamber upper is called as ___________
a) outlet displacement chamber
b) outlet discharge chamber
c) outlet density chamber
d) outlet dwell chamber
Answer: a
Explanation: Outer chamber is a rectangular shaped located just on the opposite side of the inlet chamber. The bottom opening of the outlet chamber is connected to the gate and the upper portion is much wider and is known as Outlet displacement chamber .
This set of Energy Engineering Problems focuses on “Problem involved in Biogas Production”.
1. For minimum of how many days within starting of fermentation, initiates anaerobic bacterial action?
a) 2
b) 10
c) 14
d) 20
Answer: b
Explanation: The storage of raw materials in a damp, confined space for over ten days initiates anaerobic bacterial action that, though causing some gas loss, reduces the time for the digester to become operational.
2. What should be the ratio of raw material to water?
a) 1:1
b) 4:1
c) 5:2
d) 3:6
Answer: a
Explanation: Experience has shown the raw material ratio to water should be 1:1, i.e., 100kg of excrete to 100 kg of water. In the slurry, this corresponds to a total solids concentration of 8-11 per cent by weight.
3. Higher loading rates have been used when the ambient temperature is ____________
a) High
b) Low
c) At 0 o
d) At medium temperature
Answer: a
Explanation: The size of the digester depends upon the loading, which is determined by the influent solids content, retention time and the digester temperature. Optimum loading rates vary with their different digesters and sites of location. Higher loading rates have been used when the ambient temperature is high.
4. What is the full form of TVS?
a) Tempered volatile solid
b) Total variant solid
c) Total volatile solid
d) Termed variant solid
Answer: c
Explanation: In general, the literature is filled with a variety of conflicting loading rates. In practice, the loading rate should be an expression of either Weight of total volatile solids added per day per unit volume of digest, or the weight of TVS added per day per unit weight of TVS in the digester.
5. ______________ is a major factor in determining the methane yield and methane production rates from the digestion of biomass.
a) Seeding
b) Contamination
c) Substrate composition
d) Moisture content
Answer: c
Explanation: Substrate composition is a major factor in determining the methane yield and methane production rates from the digestion of biomass. Techniques to determine the compositional characteristics of the feedstock are available, while parameters such as solids, elemental, and organic analyses are important for digester design and operation.
6. What is anaerobic digestion PH range?
a) 6.0 – 8.0
b) 1.3 – 4.2
c) 2.5 – 6.5
d) 7.2 – 10.0
Answer: a
Explanation: Low pH inhibits the growth of the methanogenic bacteria and gas generation and is often the result of overloading. A successful pH range for anaerobic digestion is 6.0 – 8.0; efficient digestion occurs at a pH near neutrality.
7. With a mesophilic flora digestion precedes best at what temperature?
a) 30 – 40 o C
b) 65 – 75 o C
c) 10 – 30 o C
d) 10 -15 o C
Answer: a
Explanation: With a mesophilic flora, digestion precedes best at 30 – 40 o C; with thermophiles, the optimum range is 50 – 60 o C. The choice of the temperature to be used is influenced by climatic considerations.
8. Which of the following two are most important nutrients?
a) Carbon and nitrogen
b) Methane and carbon
c) Methane and oxygen
d) Methane and nitrogen
Answer: a
Explanation: The maintenance of optimum microbiology activity in the digester is crucial to gas generation and consequently is related to nutrient availability. Two of the most important nutrients are carbon and nitrogen.
9. What does excess availability of nitrogen lead?
a) NO 3
b) NO 2
c) NH 3
d) NH 4
Answer: c
Explanation: Excess availability of nitrogen leads to the formation of NH 3 , the concentration of which inhibits further growth. Ammonia toxicity can be remedied by low loading or by dilution. So in practice it is necessary to maintain the levels of nitrogen.
10. How is potential toxicity, due to ammonia is corrected?
a) By dilution
b) By adding urea
c) By adjusting the temperature
d) By adding extra carbon rich content
Answer: a
Explanation: Wastes and biodegradable residue are often accompanied by a variety of pollutants that could inhibit anaerobic digestion. Potential toxicity can be corrected by remedying the C/N ratio of manure by dilution.
11. Which of the following salt group is stimulatory or toxic in action?
a) Sodium, potassium, calcium and magnesium
b) Copper, zinc, sodium and magnesium
c) Copper, calcium, magnesium and potassium
d) Sodium, magnesium, zinc, and potassium
Answer: a
Explanation: Salts of sodium, potassium, calcium and magnesium may be stimulatory or toxic in action, both manifestations being associated with the cat-ion rather than the anionic portion of the salt. Pesticides and synthetic detergents may also be troublesome to the process.
12. Agitation is performed ___________
a) Mechanically
b) Manually
c) By help of cattle
d) Feedstock
Answer: a
Explanation: Agitation can be done either mechanically or with a plunger or by means of rotational spraying of fresh influent. Agitation is normally required for both digesters, ensures exposure of new surfaces to bacterial action prevents viscid satisfaction and slow down of bacterial activity.
13. Which is the initial issue of the biogas plant?
a) Feedstock
b) Contaminants
c) Moisture contents
d) Nutrients
Answer: a
Explanation: The most important initial issue when considering the application of anaerobic digestion systems is the feedstock to the process. Almost any organic material can be processed with anaerobic digestion; however, if biogas production is the aim, the level of digestion is the key factor in its successful application.
14. The anaerobic digestion can be inhibited.
a) True
b) False
Answer: a
Explanation: The anaerobic digestion process can be inhibited by several compounds, affecting one or more of the bacterial groups responsible for the different organic matter degradation steps. The degree of the inhibition depends, among other factors, on the concentration of the inhibitor in the digester. Potential inhibitors are ammonia, sulfide, light metal ions and some organics.
This set of Energy Engineering Multiple Choice Questions & Answers focuses on “Applications of Biogas & Gasifier”.
1. What is the percentage at which rated power from biogas in petrol engine can be developed?
a) 45%
b) 65%
c) 75%
d) 85%
Answer: d
Explanation: Petrol engine can be operated on biogas after initially starting with petrol. Petrol replacement of 1005 is possible and petrol engines can develop about 85% of rated power where as diesel engine can develop full power.
2. Which engine can run on dual fuel with little engine modification?
a) Diesel engine
b) Petrol engine
c) IC engine
d) External combustion engine
Answer: a
Explanation: Diesel engine can run on dual fuel with little engine modifications. Advancing the injection timing and entry of biogas with intake air, it can be achieved by providing a mixing chamber below the air cleaner which facilitates mixing of biogas with air before entering into the cylinder.
3. Which of the SI engine can be run on biogas?
a) Diesel engine
b) Petrol engine
c) IC engine
d) External combustion engine
Answer: b
Explanation: Petrol engine can run on biogas, but it is required to be started with petrol in the beginning. Petrol engine can be modified for operation on biogas including provision for entry of biogas, throttling of intake air and advancing ignition timing.
4. What does CNG stands?
a) Converted natural gas
b) Compressed natural gas
c) Compressed Non-soluble gas
d) Compressed natural gasoline
Answer: b
Explanation: Compressed natural gas is a fuel which can be used in place of gasoline , Diesel fuel and propane/LPG. CNG combustion produces fewer undesirable gases than the fuels mentioned above.
5. What is the full form of VRA?
a) Vibration resistant appliance
b) Vehicle Refueling Appliances
c) Volatile removal assembly
d) Validated requirement authority
Answer: b
Explanation: Vehicle refueling appliance is abbreviated as VRAs. Certified natural gas compressors for refueling the vehicles are commercially available. These allow refueling at home and work. After upgrading with the above-mentioned technologies, the biogas can be used as vehicle fuel in adapted vehicles.
6. A device for converting substances into gas is called ______
a) Gasifies
b) Biogas plants
c) Draughts
d) Gas chambers
Answer: a
Explanation: The word Gasification implies converting a solid or liquid into a gaseous fuel without leaving any solid carbonaceous residue. Gasifier is a equipment which can gasify a variety of biomass such as wood waste, agricultural waste like stalks, and roots of various crops. The gasifier is essentially a chemical reactor where various complex physical and chemical processes take place.
7. How many types of gasifiers are there?
a) 2
b) 3
c) 4
d) 5
Answer: c
Explanation: There are four types of gasifiers namely:
i. Up draught or counter current gasifier.
ii. Down draught or co-current gasifier.
iii. Cross draught gasifier.
iv. Fluidized bed gasifier.
8. Which is the oldest and simplest type of gasifier?
a) Counter current gasifier
b) Cross draught gasifier
c) Co-current gasifier
d) Fluidized bed gasifier
Answer: a
Explanation: The oldest and simplest type of gasifier is the counter current or up draught gasifier. The major advantage of this type of gasifier are its simplicity, high charcoal burnout and internal heat exchange leading to low gas exit temperatures and high equipment efficiency.
9. Which is the gasifier that can be operated in small scale/amounts?
a) Counter current gasifier
b) Cross draught gasifier
c) Co-current gasifier
d) Fluidized bed gasifier
Answer: b
Explanation: It is actually the advantage of this system that it is capable of handling very small amounts for operation. Installations below 10 KW can under certain conditions be economically feasible. The reason is the very simple gas cleaning train which can be employed when using this type of gasifier.
10. Which gasifier has better tar converting capacity?
a) Counter current gasifier
b) Cross draught gasifier
c) Co-current gasifier
d) Fluidized bed gasifier
Answer: c
Explanation: A solution to the problem of tar entrainment in the gas stream has been found by designing co-current or down draught gasifiers, in which primary gasification air is introduced at or above the oxidation zone in the gasifier.
11. Which gasifier has a minimum tar converting capability?
a) Counter current gasifier
b) Cross draught gasifier
c) Co-current gasifier
d) Fluidized bed gasifier
Answer: b
Explanation: A disadvantage of cross draught gasifiers is their minimal tar converting capacity and the consequent needs for the high quality charcoal. It is because of the uncertainty of charcoal quality that a number of charcoal gasifiers employ down draught principle, in order to maintain at least a minimal tar cracking capability.
12. Which gasifier equipment has inability to operate on a number of unprocessed fuels?
a) Counter current gasifier
b) Cross draught gasifier
c) Co-current gasifier
d) Fluidized bed gasifier
Answer: c
Explanation: Down draught gasifier or co-current gasifiers equipment lies in its inability to operate on a number of unprocessed fuels. In particular, fluffy, low density materials give rise to flow problems and excessive pressure drop and the solid fuel must be pelletized before use.
