1. welcome
PRESENTATION BY
ASHISH MISHRA

2. THERMAL POWER PLANT

3. Introduction
A Thermal Power Plant converts the heat energy of coal into electrical energy. Coal is burnt in a boiler which converts water into steam. The expansion of steam in turbine produces mechanical power which drives the alternator coupled to the turbine.Thermal Power Plants contribute maximum to the generation of Power for any country
Thermal Power Plants constitute 75.43% of the total installed captive and non-captive power generation in India
In thermal generating stations coal, oil, natural gas etc. are employed as primary sources of energy.

4. General layout thermal power plant

5. Main and Auxiliary equipments
Coal handling plant
Pulverizing plant
Draft fans
Boiler
Ash handling plant
Turbine
Condenser
Cooling towers and ponds
Feed water heater
Economizer
Superheated and Reheated
Air preheated

6. Rejected- The stones and unwanted coal is rejected
Coal Handling Plant
Raw Coal Wagon- Coal is brought to the site through a Wagon as per requirement.
Wagon tippler-The coal is unloaded from the Wagon and is transported to crushers and for storage place through conveyor.
Rejected- The stones and unwanted coal is rejected
Junction tower- JT’s are used where the conveyor has any angular deviation.
Primary Crusher-The Raw coal is crushed into fine pieces to 45mm grit). Primary crusher is also called Rotary Breaker since the coal is crushed by a rotating plate.

7. Secondary Crusher-The fine pieces of coal is crushed to
Secondary Crusher-The fine pieces of coal is crushed to powder (to 25mm grit)
Two way conveyor
Junction Tower
Stacker & Reclaimer- It is used to store the powdered coal for emergency purpose
Mill Bunker-The 25mm grit coal is crushed into very fine powder for feeding the boiler. We will have a spare Bunker for each Boiler.
Atmospheric air (Through FD fan)
BOILER

8. Pulverizing plant Contact mill Ball mill Impact mill
In modern thermal power plant , coal is pulverized i.e. ground to dust like size and carried to the furnace in a stream of hot air. Pulverizing is a means of exposing a large surface area to the action of oxygen and consequently helping combustion.
Pulverizing mills are further classified as:
Contact mill
Ball mill
Impact mill

9. Draft system Natural draft Mechanical draft
The circulation of air is caused by a difference in pressure, known as Draft.
Draft is a differential pressure b/w atmosphere and inside the boiler.
It is necessary to cause the flow of gases through boiler setting
It may be –
Natural draft
Mechanical draft

10. Boiler
The boiler is fed with HFO and LDO initially to ignite the coal in the Boiler.
Types of boilers:
Water tube Boiler: A boiler in which water circulates in tubes heated externally by the fire.
Fire tube Boiler: Water is present in the drum inside the boiler and Hot air is circulated around maintain the temperature.
Fuel
HFO,LDO & Coal
Air
Boiler
Fuel
HFO,LDO & Coal
Air
Dryer
Air compressor
The fuel and air are feed from 2 directions to increase the efficiency
FD Fan
Atmospheric Air

11. Ash Handling Plant The Ash from the boiler is collected in two forms:
Flue Gases
The Ash from the boiler is collected in two forms:
Bottom Ash(Slurry):It’s a waste which is dumped into a Ash Pond
Fly ash: Fly ash is separated from Flue Gases in ESP(Electro static Precipitator).
Economizer : Reduces the temperature
Chimney
Fly Ash & Flue Gases
Economizer
ESP
Boiler
Flue Gases
Bottom ash(wet ash)
Fly ash
Ash Pond
Cylo
Cement Factory

12. Turbine Condenser HPT IPT LPT RH
In a Thermal Power Plant generally 3 turbines are used to increase the efficiency.
High Pressure Turbine(HPT): The superheated steam is directly fed to this turbine to rotate it.
Intermediate Pressure Turbine(IPT): The out put from the HPT is reheated in a reheated(RH) and used to rotate IPT .
Low Pressure Turbine(LPT): The Exhausted steam from the IPT is directly fed to rotate the shaft of LPT.
*All the turbines are connected to a single shaft which is connected
to the Generator.
Super Heater
Steam
Shaft
Generator
HPT
IPT
LPT RH
Steam
Condenser

13. CONDENSER
Steam after rotating steam turbine comes to condenser. Condenser refers here to the shell and tube heat exchanger (or surface condenser) installed at the outlet of every steam turbine in Thermal power stations of utility companies generally.

14. Cooling towers and ponds
A condenser needs huge quantity of water to condense the steam .
Typically a 2000MW plant needs about 1500MGallon of water.
Most plants use a closed cooling system where warm water coming from condenser is cooled and reused
Small plants use spray ponds and medium and large plants use cooling towers.
Cooling tower is a steel or concrete hyperbolic structure having a reservoir at the base for storage of cooled water
Height of the cooling tower may be 150 m or so and diameter at the

15. Feed water heater
Advantages of heating water before feeding back to the boiler:-
Feed water heating improves overall plant efficiency.
The dissolved oxygen and carbon dioxide which would otherwise cause boiler corrosion are removed in feed water heater
Thermal stresses due to cold water entering the boiler drum are avoided.
Quantity of steam produced by the boiler is increased.
Some other impurities carried by the steam and condensate, due to corrosion of boiler and condenser are precipitated outside the boiler

16. Economizer
Flue gases coming out of the boiler carry lot of heat. An economizer extracts a part of this heat from flue gases and uses it for heating feed water. This use of economizer results in saving coal consumption and higher boiler efficiency

17. Super heater and Reheaters
Super heater is a component of a steam- generating unit in which steam, after it has left the boiler drum, is heated above its saturation temperature
Reheater : Some of the heat of superheated steam is used to rotate the turbine where it loses some of its energy

18. Air preheaters
After flue gases leave economizer, some further heat can be extracted from them and used to heat incoming heat. Cooling of flue gases by 20 degree centigrade increases the plant efficiency by 1%.
Air preheaters may be of three types
Plate type
Tubular type
Regenerative type

19. Water Handling Plant(WHP)
Water in a Power Plant is used for
Production of Steam- for rotating turbine.
Cooling Purpose- For cooling of various equipment .
Water is recycled and used for various purpose:
Raw Water
Condenser
Purified DM water
Steam
For cooling purpose
3% of water is wasted during this process. Appx 4 cubic mt water is lost /day/MW

20. (Demineralized Plant)
Reservoir
Water Cycle
Water Clarification
DM Plant
(Demineralized Plant)
Chlorification
&
Filtration
DMCW Demineralized cooling Water
Auxiliary cooling
Water (ACW)
Various Equipment
Cooling Water
Various Equipment
Boiler
DMCWP
Steam
PHE
Condenser
Cooling Tower CT
25D  35D
Steam to Water
water
Hot water CT
25D  20D
Cool water from CWP
CWP
CWP
CWP
Cool water
D-Degrees
CWP-cooling water Pump
PHE-Pre heat Exchange
Dearator
Hot Well

21. Operation Mechanism
The coal is brought and crushed to powder. This is feed to Boiler for producing heat
In Boiler the water is converted to steam.
In Super heater the moisture content is removed from the steam and that steam is called super heated steam
The superheated steam rotates the shaft of the High pressure turbine
The Exhausted steam is sent to preheater and the steam then rotates the Intermediate pressure(IP) Turbine
The steam from the IP turbine is then feed to low pressure turbine.
The turbine shaft is connected to the Generator, which produces Electric Power.
The power generated is then Transmitted.

22. Generator
The Synchronous Generator is used to Generate power by connecting the shaft of the Turbine to the shaft of the generator which cuts the magnetic flux producing Emf.
The Generated Voltage will generally 11KV to 20 KV max.
The Generated Voltage is stepped up by connecting Step up transformer and is transmitted and is also used for Auxiliary purposes.
UAT
20Kv to 6.KV
Bus Duct
SYNCHRONOUS
GENERATOR
Generator Transformer
20KV to 400KV
Unit Auxiliary Transformer: This transformer is used to step down the produced voltage and use for Auxiliary purpose.

23. THANK YOU ! !