1. STEAM POWER PLANTS

2. SELECTION OF SITE FOR STEAM POWER PLANT
Availability of land
Availability of sufficient amount of good boiler feed water and cooling water
Availability of fuel.
Necessity for future expansion.
Availability of other power other power services
Away from urban areas
Initial cost of plant
Magnitude and nature of load to be handled

3. LAY OUT OF STEAM POWER PLANT

5. GENRAL LAYOUT Fuel handling unit Ash handling unit Boiler unit
Feed water unit
Cooling water unit
Generator unit
Turbine unit

6. MAIN FLOW CIRCUITS Fuel and ash circuit Air and gas circuit
Feed water and steam circuit
Cooling water circuit

7. FUEL AND ASH CIRCUIT
Fuel stored is fed to boiler through conveyer belt.
Coal – particular size for complete burning.
Coal is passed through crushers , sizers and magnetic separators before feeding to boiler.
As a result of combustion, ash is produced from coal fuel which is removed from boiler through ash handling equipments.

8. AIR AND GAS CIRCUIT
Air is required for complete combustion of the fuel – supplied through Forced draught(FD) and Induced draught(ID) fans.
Air which is fed to the boiler, is passed through preheater – to extract energy of flue gases from boiler.
Flue gas consist of several gases and ash – passed through precipitator and finally go to atmosphere via chimney .

9. FEED WATER AND STEAM CIRCUIT
Most power plants are condensing type – steam is converted to water by condenser.
For safety of turbine water is demineralized – better economic operation
Adding make up water in feed water system compensate leakages.
The boiler feed pump (BFP) feeds water to boiler drum – heated to form steam.
Wet steam heated in super heater passed to turbine and runs it

10. FEED WATER AND STEAM CIRCUIT
Stages of prime mover depending on size of power plant
High Pressure Turbine HP
Intermediate Pressure Turbine IP
Low Pressure turbine LP

11. FEED WATER AND STEAM CIRCUIT

12. COOLING WATER CIRCUIT
To condensate the steam in condenser and maintaining low pressure in it, large quantity of cooling water is required.
After passing it through condenser, it is fed back to river or pondage.
Cooling tower or cooling ponds are used in case of shortage.
Drawback- Excessive water loss

13. PARTS OF STEAM POWER PLANT
Boiler- Water tube boiler
Coal Mills
Boiler feed pump- high capacity IM
Air preheater- extract heat from flue gases
Draught system- supply air to the furnace and to take the flue gases from the boiler
Economizers- extract heat from flue gases

14. PARTS OF STEAM POWER PLANT
Superheaters and Reheaters
Turbines
Condenser
Cooling tower
Alternators- high speed synchronous generators

15. COOLING OF ALTERNATOR
Important due to damage of insulation at high temperature.
Closed circuit cooling widely used in modern alternators (Hydrogen as cooling medium).

16. ADVANTAGES OF HYDROGEN COOLING
More heat transfer and thermal conductivity is 7 times more than air.
Low ventilation losses
Life of insulation is more as no oxidation of insulating material .
Fire hazards minimized
Less noise
Size of frame reduced

17. DISADVANTAGES OF HYDROGEN COOLING
Chances of formation of explosive mixture.
Expensive than air
Special oil seals required
Problem of ensuring complete tightness of hydrogen