POWER GENERATION QUESTION AND ANSWER

 THERMAL POWER PLANT QUESTION AND ANSWER

Q:List the factors to be considered while choosing a site for steam power station:
1.Supply of fuel
2.Availability of water
3.Transportation facilities
4.Cost and type of land
5.Nearness to load centres
6.Distance from populated area

Q: Explain the working of thermal power plant.

It uses coal as the primary fuel to boil the water available to superheated steam for driving the steam turbine. The steam turbine is then mechanically coupled to an alternator rotor, the rotation of which results in the generation of electric power.

Q.Why the preparation of coal is necessary?

The coal from coal nines cannot be directly fed into the furnace. Proper preparation of coal should be done before feeding the coal to the furnace. In the coal preparation, the coal passes through the different equipments like 1.Crushers 2. Sizers 3. Driers and Magnetic Separators.

Q:What is superheater?

A superheater is a device used to convert saturated steam or wet steam into dry steam 

Q: What is an Economizer?

An economizer is a mechanical device which is used as a heat exchanger by preheating water by recovering residual heat from the flue gases in thermal power plant.

Q: what is efficiency of thermal power plant?

Installed plant capacity	Average overall thermal efficiency
upto 1MW	4%
1MW to 10MW	12%
10MW to 50MW	16%
50MW to 100MW	24%
above 100MW	27%

Q: What is the function of Air preheater?

Air pre heater is used to transfer heat from the flue gases to the air before it passes into the furnace for combustion thereby increasing the thermal efficiency of the process. 

Q: Name the four major circuits in steam power plant.
•  Coal and ash circuit
•  Air and flue gas circuit
•  Feed water and steam circuit
•  Cooling water circuit

Q: What consists of air and flue gas circuit?
  Air  and  flue  gas  circuit  consists  of  forced  draught  fan,  air-pre-heater,  boiler,  furnace,
super heater, economizer, dust collector, induced draught fan and chimney.

Q: What consists of feed water and steam flow circuit in steam power?
The  feed  water  and  steam  flow  circuit  consists  of  feed  pump,  economizer  boiler  drum
super heater, turbine and condenser.

Q: What consists of cooling water circuit and coal & ash circuit in steam power plant?
 The cooling water circuit consists of a pump, condenser and cooling tower. The coal and
ash circuit consists of coal delivery, preparation  of coal, handling of coal to the boiler furnace,
ash handling and ash storage.

Q:What is meant by cooling Towers? 
It is a tower or building like device in which atmospheric air circulates in direct or 
indirect contact with warmer water and water is thereby cooled. Cooling towers may 
either use the evaporation of water to remove process heat and cool the working fluid


Q:List the types of super heaters: 
1. Radiant super heater- absorb heat by radiation 
2. Convention super heater-absorb heat via a fluid 
3. Separately fixed super heaters- it is totally separated from the boiler

Q.What are different types of Steam boilers used in Thermal Power Plants?
 Different type of boiler used in thermal power plants are:

• Fire tube boiler

• Water tube boiler

• Natural Circulation boiler

• Forced Circulation boiler

• Once through boiler

Q. What is the working principle of Cooling Towers?

The hot water is sprayed from the top of the tower, while the air is made to flow from the bottom of the tower to the top. This air cools the hot water in the cooling tower. Air vaporises a small percentage of water, there by cooling the remaining water. The air absorbs the heat and leaves at the top of the tower and cooled water leaves at the bottom and recirculated to the condenser.

Q.Define draught, what is the use of draught in thermal power plants?

 Draught is defined as a small pressure difference required between the fuel bed (furnace) and outside air to maintain constant flow of air and to discharge the gases through chimney to the atmosphere. Draught can be obtained by chimney, fan, steam jet (or) ‑air jet (or) combination of these.

The uses are

·         To supply required quantity of air to the furnace for combustion of fuel.

·         To draw the combustion products through the system.

·         To remove burnt products from the system

Q. Write about classification of draught?

 Draught is classified as

            1. Natural draught

            2. Artificial draught

HYDRO POWER PLANT QUESTION AND ANSWER

Q:List the types of hydro power plants based on availability of head; 
1. High head power plant(head>100m) 
2. Medium head power plant(30m-100m) 
3. Low head power plants(head<30m) 

Q:What are the essential elements of hydro power plant? 
1. Catchment area 
2. Reservoir
3. Dam 
4. Surge tanks 
5. Draft tubes 
6. Power house 
7. Switched for transmission of power

Q:What is meant by catchment area and explain its function: 
The whole area behind the dam is called the catchment area. The rain water in the area will be drained into the dam through a dam or river. 

Q:  What is the main purpose of the reservoir?
The main purpose of reservoir is to store water received from catchments areas during the
rainy seasons and supply the same during the dry season.

Q: What is the main purpose of the dam?
The main purpose of the dam is to increase the height of water level and also to increase
the working head of the hydraulic power plant.

Q: Why trash rack is used?
The  trash  rack  is  used  to  prevent  the  entry  of  debris,  which  might  damage  the  turbine runners and chock up the nozzle of impulse turbine.

Q: What is the use of surge tank?
The surge tank is used to provide better regulation of water pressure in the system. The
surge tank controls the water when the load on the turbine decreases and supplies water when the load on the turbine increases. Thus, surge tank controls the pressure variations resulting from the rapid changes in water flow in penstock and hence prevents water hammer.

Q:What is the function of Fore bay?
 Fore  bay  is  considered  as  naturally  provided  surge  tank.  It  is  temporary  water  storage when the load on the plant is reduced and provides water for initial increment on increasing load.

Q: Explain about penstock?
 The pipe between surge tank and prime mover is known as penstock.  It  is designed to
withstand high pressure. It is made up of reinforced concrete. In very cold areas, the penstock is buried to prevent ice formation and to reduce the expansion joints.

Q: What is the use of spill Ways?
Spillway is like a safety valve of the dam. It discharges major flood without damaging the
dam. It keeps the reservoir level below the maximum level allowed.

Q: Write about prime movers?
Prime  mover  converts  the  kinetic  energy  of  water  into  mechanical  energy  to  produce
electrical energy. Pelton wheel  turbine, Francis turbine, Kaplan turbine and Propeller turbine are prime movers used in hydraulic power plants.

Q:What is power house? 
A power house is a stable structure which houses the equipment in the power plant 

Q:What is meant by pumped storage power plant? 
The pumped storage plants are used for load balancing. During peak load water is 
used to work on turbines to produce electricity. Water after working in turbines is stored 
in the tail race reservoir. 

Q:Explain reaction turbine in terms of head: 
High head- Francis 
Medium head- Propeller 
Low head- Kaplan 

NUCLEAR POWER PLANT QUESTION AND ANSWER

Q: Name the different components of nuclear reactor?
  1. Nuclear fuel  2. Moderator   3. Control rods
  4. Reflectors   5. Reactor vessel  6. Biological shielding
  7. Coolant

Q.Which is the nuclear fuel used ?
The  commonly used fuels are Uranium, Plutonium or Thorium. It can be U-235, U-238, Pu-236 or Th-232. Uranium is mostly preferred as it has high melting point. 

Q.what is function of Moderator in nuclear reactor?

The moderator is a material which slows down the speed of the neutrons. The moderator is

usually made from water but some reactors use graphite also.Neutrons released from the chain reaction must be moving properly for other atoms of uranium to capture them.If the neutrons are moving too fast then they do not get captured by the nucleus of another uranium atom and the chain reaction stops. The moderator slows the neutrons down so that they can be captured and keep the chain reaction going.

Q:Define water as moderator. 
Neutrons from fission have very high speeds and must slowed greatly by water moderation to maintain the chain reaction.

Q. What is the function of control rod in nuclear reactor?
These rods absorb neutrons and stop the chain reaction to proceed further.. Some control rods are made from an alloy of silver and cadmium. Some are made from boron mixed with iron or carbon. The control rods are very good at absorbing neutrons. They reduce the number of neutrons available to continue the chain reaction. The control rods can be moved up and down inside the reactor core. As they are lifted up and out of the reactor, the less neutrons they absorb, the faster the chain reaction happens and the reactor gets hotter. The heat is then used to generate electricity. The further down
the control rods go, the more neutrons they absorb, the slower the chain reaction happens and the reactor gets colder.The control rods can used to shut the reactor down completely.


Q.What is the function of shielding?
Shielding prevents radiations to reach outside the reactor. Lead blocks and concrete enclosure that is strong enough of several meters thickness are used for shielding.

Q.What is the function of coolant?
Heat is absorbed by the coolant that is produced in the reactor. Typical coolants are water, carbon dioxide gas or liquid sodium. 

GAS AND DIESEL POWER PLANT QUESTION AND ANSWER

Q:What are the working fluids in gas turbine? 

1.Air 

2.Helium 

3.Argon 

4.Carbon dioxide

Q:List the various types of diesel plants. 

Based on number of strokes: 

(a) Two stroke diesel engine 

(b) Four srtoke diesel engine 

Based on orientation: 

(a) Horizontal diesel engine 

(b) Vertical diesel engine 

Based on number of cylinders: 

(a) single cylinder 

(b) Multi cylinder 

And other type like naturally aspirated, superheated etc., 

Q: List the components of diesel power plant. 

1.Diesel engine 

2. Air intake system 

3. Exhaust system 

4. Fuel system 

5. Cooling system 

6. Lubricating system 

7. Starting of engine

Q: List any four applications of diesel power plant. 

1. Used as peak load plants 

2. Suitable for mobile plants 

3. Used as standby units 

4. Used as emergency plant