The document discusses different types of power plants and steam boilers. It describes the key components and circuits of a steam power plant which uses coal as fuel. Various types of steam boilers are explained, including fire tube boilers, water tube boilers, high pressure boilers, supercritical boilers, and fluidized bed boilers. Fluidized bed boilers allow the combustion of low grade fuels and have lower emissions. They operate at lower temperatures than conventional boilers.

1. G.K.Manikandan
Professor, Department of Mechanical Engineering,
SSM College of Engineering
Komarapalayam, Namakkal District - 638183
Tamil Nadu

3. INTRODUCTION OF POWER
PLANTS & BOILERS
 POWER - Inevitable
 ELECTRICITY
EASY TO
GENERATE
TRANSPORT &
CONTROL

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

9. LAYOUT OF STEAM POWER PLANT

10. LAYOUT OF STEAM POWER PLANT

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

18. COCHRAN 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

21. TYPES OF BOILERS
1. High pressure boilers
2. Super critical boilers

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

24. LAMONT BOILER – 170 bar & 50 tonnes / hr

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

26. BENSON BOILER – 750 Tonnes / hr

27. LOEFFLER BOILER – 100 Tonnes / hr

28. VELOX BOILER

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

34. FLUIDIZED BED COMBUSTION - Principle

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.

38. BUBBLING FLUIDIZED BED BOILER

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

40. CIRCULATING FLUIDIZED BED BOILERS - CFB

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

43. PRESSURIZED FLUIDIZED BED BOILER

44. PRESSURIZED CIRCULATING FLUIDIZED
BED BOILER

45. ATMOSPHERIC BUBBLING FBB

46. ATMOSPHERIC CIRCULATING BUBBLING FBB