This document describes the key components and processes involved in a thermal power plant. Water is heated to produce steam, which spins turbines connected to generators to produce electricity. The main components are the boiler, turbines, condenser, cooling tower and auxiliary systems. Coal is pulverized and burned in the boiler to heat water and produce high pressure steam. The steam powers high, intermediate and low pressure turbines in succession to generate electricity before being condensed back into water in the condenser. The water is cooled in the cooling tower and recycled to the boiler to repeat the process.

1. THERMAL POWER PLANT
A thermal power plant is a power plant in which the prime mover is stream. Water
is heated, turns into steam and spins a turbine which drives an electrical generator.
After it passes through the turbine, the steam is condensed in a condenser and
recycled to where it was heated; this is known as a Rankine cycle.

2. A coal-fired thermal power station.
1. Cooling tower. 2. Cooling water pump. 3. Transmission line (3-phase). 4. Unit
transformer (3-phase). 5. Electric generator (3-phase). 6. Low pressure turbine. 7.
Condensate extraction pump. 8. Condenser. 9. Intermediate pressure turbine. 10.
Steam governor valve. 11. High pressure turbine. 12. Deaerator. 13. Feed heater. 14.
Coal conveyor. 15. Coal hopper. 16. Pulverised fuel mill. 17. Boiler drum. 18. Ash
hopper. 19. Superheater. 20. Forced draught fan. 21. Reheater. 22. Air intake. 23.
Economiser. 24. Air preheater. 25. Precipitator. 26. Induced draught fan. 27. Chimney
Stack.

3. WORKING SYSTEM
Coal is conveyed (14) from an external stack and ground to a very fine powder by large metal spheres in
the pulverised fuel mill (16). There it is mixed with preheated air (24) driven by the forced draught fan
(20). The hot air-fuel mixture is forced at high pressure into the boiler where it rapidly ignites. Water of a
high purity flows vertically up the tube-lined walls of the boiler, where it turns into steam, and is passed
to the boiler drum, where steam is separated from any remaining water. The steam passes through a
manifold in the roof of the drum into the pendant superheater (19) where its temperature and pressure
increase rapidly to around 200 bar and 570°C, sufficient to make the tube walls glow a dull red. The steam
is piped to the high pressure turbine (11), the first of a three-stage turbine process. A steam governor valve
(10) allows for both manual control of the turbine and automatic set-point following. The steam is
exhausted from the high pressure turbine, and reduced in both pressure and temperature, is returned to
the boiler reheater (21). The reheated steam is then passed to the intermediate pressure turbine (9), and
from there passed directly to the low pressure turbine set (6). The exiting steam, now a little above its
boiling point, is brought into thermal contact with cold water (pumped in from the cooling tower) in the
condensor (8), where it condenses rapidly back into water, creating near vacuum-like conditions inside
the condensor chest. The condensed water is then passed by a feed pump (7) through a deaerator (12),
and pre-warmed, first in a feed heater (13) powered by steam drawn from the high pressure set, and then
in the economiser (23), before being returned to the boiler drum. The cooling water from the condensor
is sprayed inside a cooling tower (1), creating a highly visible plume of water vapor, before being pumped
back to the condensor (8) in cooling water cycle.
The three turbine sets are sometimes coupled on the same shaft as the three-phase electrical generator
(5) which generates an intermediate level voltage (typically 20-25 kV). This is stepped up by the unit
transformer (4) to a voltage more suitable for transmission (typically 250-500 kV) and is sent out onto the
three-phase transmission system (3).
Exhaust gas from the boiler is drawn by the induced draft fan (26) through an electrostatic precipitator
(25) and is then vented through the chimney stack (27).

4. COAL FEEDING SYSTEM
Coal is conveyed through rail wagon from out side of
plant and through conveyor system collected in hopper
and ground to a very fine powder by large metal spheres
in the pulverised fuel mill.
Conveyor Coal Hopper
Pulverised Mill
Wagon Tippler

5. COAL FEEDING SYSTEM
Then it is mixed with preheated air driven by the forced draught fan. The hot air-
fuel mixture is forced at high pressure into the boiler.
Air Pre-heater Forced Draft Fan

6. Wagon Tippler 1 &
2
Wagon Tippler 3 &
4Sloping Conveyor
Tunnel
TP-3
Conveyor 3A/3B
CHP Retaining
Wall
Overview of Under construction BOP- Coal Feeding System

7. Crusher House
TP-4
TP-5
Conveyor
4A/4B Conveyor 5A/5B
Stacker Reclaimer
Coal Stock Yard
Overview of Under construction BOP- Coal Feeding System

8. BOILER
A boiler or steam generator is a device used to
create steam by applying heat energy to water.
The steam generator or boiler is an integral component of a steam engine when
considered as a prime mover; The boiler is a furnace on a side. Its walls are made of
a web of high pressure steel tubes.
Pulverized coal is air-blown into the furnace from fuel nozzles at the four corners
and it rapidly burns, forming a large fireball at the center. The thermal radiation of
the fireball heats the water that circulates through the boiler tubes near the boiler
perimeter. The water circulation rate in the boiler is three to four times the
throughput and is typically driven by pumps. As the water in the boiler circulates it
absorbs heat and changes into steam at 700 °F (371 °C) and 3,200 psi . It is separated
from the water inside a drum at the top of the furnace.

9. Overview of Under construction Boiler System

10. ASH HANDLING SYSTEM
At the bottom of the furnace, there is a hopper for collection of bottom ash. This
hopper is always filled with water to quench the ash and clinkers falling down from
the furnace. Some arrangement is included to crush the clinkers and for conveying
the crushed clinkers and bottom ash to a storage site.

11. SUPER HEATER
In a power plant, after the steam is conditioned by the drying equipment inside the
steam drum, it is piped from the upper drum area into tubes inside an area of the
furnace known as the super heater, which has an elaborate set up of tubing where
the steam vapor picks up more energy from hot flue gases outside the tubing and
its temperature is now superheated above the saturation temperature. The
superheated steam is then piped through the main steam lines to the valves before
the high pressure turbine.
Superheated steam is steam at a
temperature higher than water's boiling
point. If saturated stream is heated at
constant pressure, it increases toward
100% Dry Saturated Steam. Continued
heat input will then generate superheated
steam. This will occur if saturated steam
contacts a surface with a higher
temperature. The steam is then described
as superheated by the number of degrees
it has been heated above saturation
temperature

12. STEAM TURBINE
The hot reheat steam is conducted to the intermediate pressure turbine where it
falls in both temperature and pressure and exits directly to the long-bladed low
pressure turbines and finally exits to the condense
A steam turbine is a mechanical device
that extracts thermal energy from
pressurized steam, and converts it into
rotary motion.
The steam turbine is a form of heat engine
that derives much of its improvement in
thermodynamics efficiency through the
use of multiple stages in the expansion of
the steam.

13. CONDENSER
Condenser is a device or unit used to condense a substance from its gaseous to its
liquid state, typically by cooling it.
The exiting steam from steam turbine, now a little above its boiling point, is
brought into thermal contact with cold water (pumped in from the cooling tower)
in the condenser. where it condenses rapidly back into water, creating near vacuum-
like conditions inside the condenser chest.
Water Cooled Condenser Air Cooled Condenser

14. COOLING TOWER
Natural Draft Cooling
Tower
Induced Draft Cooling Tower
Cooling towers are heat removal devices used to transfer process waste heat to
the atmosphere. Cooling towers either use the evaporation of water to remove
process heat and cool the working fluid or in the case of closed circuit dry cooling
towers rely solely on air to cool the working fluid.

15. NDCT
Overview of Under construction NDCT

16. DE AREATOR
De Areator
The condensed water is then passed by a feed pump through a deaerater.
A deaerator is a device that is widely
used for the removal of air and other
dissolved gases from the feed water to
steam-generating boiler.

17. ECONOMISER
Economiser
Pre-warmed water first enter in a feed heater
powered by steam drawn from the high
pressure set, and then in the economiser
Economizer are mechanical devices intended
to reduce energy consumption, or to perform
another useful function like preheating a fluid.
Economizer is a flue gas to water heat exchanger. Usually it is located below the
LPSH in the boiler and above Air pre heater. Outside surface of the economizer tubes
are heated by flue gases leaving the superheater and reheater which subsequently
transfer heat to feed water flowing inside the tubes.
Advantages of Economizer include
1) Fuel economy: – used to save fuel and increase overall efficiency of boiler plant.
2) Reducing size of boiler: – as the feed water is preheated in the economizer and
enter boiler tube at elevated temperature. The heat transfer area required for
evaporation reduced considerably.

18. Electrostatic Precipitator
Exhaust gas from the boiler is drawn by the induced draft fan through an
electrostatic precipitator
Electrostatic precipitators are mandatory installation in modern power plants to
control stack emission. Each boiler has electrostatic precipitators which contain
high voltage electrodes, these attract the pulverized fuel ash (PFA) from the flue
gases. At regular intervals the electrodes are rapped with motor-driven hammers
and the PFA falls into hoppers below.
Electrostatic precipitator is a collection
device that removes particles from a flowing
gas (such as air) using the force of an induced
electrostatic charge. Electrostatic
precipitators are highly efficient filtration
devices that minimally impede the flow of
gases through the device, and can easily
remove fine particulate matter such as dust
and smoke from the air stream.

19. Under Errection : Electrostatic Precipitator

20. CHIMNEY
Exhaust gas from electrostatic precipitator vented through the chimney tack.
A chimney is a structure for venting hot
gases or smoke from a boiler, furnace or
fireplace to the outside atmosphere.
A chimney is a vertical structure for venting
hot flue gases or smoke from a boiler to the
outside atmosphere by means of the stack
effect. The space inside a chimney is called
aflue. The height of chimneys plays a role in
their ability to transfer flue gases using stack
effect. The dispersion of pollutants at higher
altitude helps to ease down its influence on
surroundings and reduces their
concentrations in compliance with regulatory
limits.

21. AUXILIARY SYSTEMS
Boiler make-up water treatment plant and
storage
Fuel Oil System
Generator Cooling
Other Structure

22. BOILER MAKE-UP WATER TREATMENT PLANT & STORAGE
Boiler make-up water treatment plant and storage
Since there is continuous withdrawal of steam and
continuous return of condensate to the boiler, losses
due to blowdown and leakages have to be made up to
maintain a desired water level in the boiler steam
drum. For this, continuous make-up water is added to
the boiler water system. Impurities in the raw water
input to the plant generally consist of calcium and
magnesium salts which impart hardness to the water.
Hardness in the make-up water to the boiler will form
deposits on the tube water surfaces which will lead to
overheating and failure of the tubes. Thus, the salts
have to be removed from the water, and that is done by
a water demineralising treatment plant

23. FUEL OIL SYSTEM
An auxiliary oil system pump is used to supply oil
at the start-up of the steam turbine generator. It
supplies the hydraulic oil system required for
steam turbine's main inlet steam stop valve, the
governing control valves, the bearing and seal oil
systems, the relevant hydraulic relays and other
mechanisms.
Light oil used as the fuel for igniters. Light oil is also required for warming up oil
guns to start the boiler from cold conditions.

24. TURBO GENERATOR
Turbo Generator - Generator consisting of a steam turbine coupled to an electric
generator for the production of electric power. They are usually preferred, since
they offer much better fuel efficiency and are also more reliable, but on the other
hand they are much heavier and need more space.

25. GENERATOR COOLING
Hydrogen gas is used for generator cooling. So
supply of pure hydrogen is essential for generator
filling and maintaining of hydrogen gas pressure
inside the generator casing.
Hydrogen Plant
Direct current passes through caustic potash and DM water for hydrogen gas
production .

26. OTHER STRUCTURE – AERATOR & CLARIFLOCCULATOR
Aeration is the process of bringing water and
air into close contact in order to remove
dissolved gases, such as carbon dioxide, and to
oxidize dissolved metals such as iron. It can
also be used to remove volatile organic
chemicals (VOC) in the water.
As lot of water used in thermal plant for various purpose. Structure to clear it from
undesirable gases & dirt are required. Raw water generally supplied from pond are
first pass through aerators which remove gases by mixing water with air.

27. OTHER STRUCTURE – AERATOR & CLARIFLOCCULATOR
Aeration is the process of bringing water
and air into close contact in order to
remove dissolved gases, such as carbon
dioxide, and to oxidize dissolved metals
such as iron. It can also be used to remove
volatile organic chemicals (VOC) in the
water.

28. Raw Water Pump House
Raw Water Reservoir
Chemical
House
Pipe Rack PR-
32
Cascade
Aerator
Sludge Pit
HRSCC -1B
Back Wash
Pit
HRSCC – 1A
Rapid Gravity Sand
Filter Filter Water Tank & Pump
House
Overview of Under construction BOP- Raw Water System

29. DM Plant
DM Tanks
Neutralization Pit
DM Regeneration
Area
Overview of Under construction BOP- De-mineralization System