5. TYPES OF POWER PLANTS
THERMAL WIND
NUCLEAR TIDAL
HYDROELECTRIC PHOTO VOLTAIC
GAS TURBINE SOLAR
GEOTHERMAL BIO – GAS
6. SELECTION OF SITE FOR POWER PLANT
Depending on the load requirement.
Availability of fuel and water.
Availability of fuel storage facility.
Transportation facility.
Availability of land.
7. SELECTION OF SITE FOR POWER PLANT
Environmental condition.
Efficiency of the plant.
Capacity of the plant.
Distance from the load centre
Noise level
8. STEAM / THERMAL / COAL POWER PLANT
INTRODUCTION
Fossil fuels (Coal) are burnt
11. MAIN CIRCUITS OF STEAM POWER PLANT
Coal & Ash
Air & Flue gas
Water & Steam
Cooling water
12. COMPONENTS OF STEAM POWER PLANT
Coal supply
Coal Pulverizer
Boiler
Precipitators and stack
13. COMPONENTS OF STEAM POWER PLANT
Turbine and generator
Transformer and transmission lines
Water purification
Ash systems
Condensers and cooling water system
14. STEAM BOILERS
A Closed vessel in which steam is generated
from the water by using heat energy.
Classification
Fire tube (or) smoke tube boiler
Water tube boiler
15. FIRE TUBE:
Hot gas passes through the tubes and the water
circulates around the tubes
EXAMPLE:
Cochran, Lancashire & Locomotive boiler
16. FIRE TUBE:
Hot gas passes through the tubes and the water
circulates around the tubes
EXAMPLE:
Cochran, Lancashire & Locomotive boiler
17. FIRE TUBE:
Hot gas passes through the tubes and the water
circulates around the tubes
EXAMPLE:
Cochran, Lancashire & Locomotive boiler
19. WATER TUBE BOILER:
Water circulates through a large number of tubes
and the hot gases pass around the tubes
EXAMPLE:
Babcock , Wilcox boiler and Stirling boiler.
20. Comparison between Fire-tube & water-tube boilers
S no. Particulars Fire tube boilers Water tube boilers
1. Mode of firing Internally fired Externally fired
2. Rate of steam
production
lower Higher
3. Construction Difficult Simple
4. Treatment of water Not so necessary More necessary
5. Operating pressure Limited to 16 bar Under high pressure as
100 bar
22. High pressure boilers
Steam pressure greater than 80bar at 500 ˙C
Steam Generation 250 tonnes / hour
Low grade fuels can be burned easily.
These are water tube boilers and use
pulverized coal firing
23. TYPES OF HIGH PRESSURE BOILERS
Lamont boiler
Benson boiler
Loeffler boiler
Velox boiler
25. Economizer
To preheat the feed water using the exhaust gases.
This increases the efficiency of the boiler
Air preheater
To preheat the air by using exhaust gases flowing
29. SUPER CRITICAL BOILER:
Steam pressure ranges from 125bar and
510˙C to 300bar and 600˙C.
These are basically classified into Sub
critical and Super critical boilers.
30. The Sub –critical boiler consists of
Economiser
Evaporator
Superheater
31. The Super –critical boiler consists of
Economiser
Superheater
In recent times the super critical boilers
above 300MW capacity units are available.
32. ADVANTAGES OF SUPER CRITICAL BOILER:
High thermal efficiency.
Heat transfer rate is high.
The erosion and corrosion are minimised
It can be used as peak load boiler
33. FLUDIZED BED BOILER
Steam is raised by the combustion of fossil
& waste fuels in a bed
Pollution is less
35. FLUIDIZED BED COMBUSTION - Principle
Feed Material always remain in suspension due to
high velocity of inlet air
SO2 emission is controlled by the addition of lime
stone or dolomite in the bed
NOx production is reduced due to low excess air &
low temperatures of bed
36. TYPES OF FLUIDIZED BED BOILER
Bubbling fluidized bed boiler(BFB)
Circulating fluidized bed boiler(CFB)
37. BUBBLING FLUIDIZED BED BOILER
In this boiler , the crushed coal (about 6-20mm)
is injected into the fluidized bed of limestone at
the bottom of the bed.
39. BUBBLING FLUIDIZED BED BOILER
The cyclone separator feeds back the carbon particles
to the bed again
Formation of H2 SO4 is reduced since limestone
retains sulphur present in the coal
Low combustion temperatures ( 800 – 9000 C) results
in the usage of inferior grade coals
41. CIRCULATING FLUIDIZED BED BOILER
The circulating fluidized bed boiler is divided into
two sections.The first section consists of
Furnace or fast –fluidized bed
Cyclone separator
Solid recycle device
External heat exchanger
42. CIRCULATING FLUIDIZED BED BOILER
The second section is the back pass. Here
remaining heat from the flue gas is absorbed by
Reheater / Super heater
Economiser
Air preheater