INDUSTRIAL TRAINING

AT

NATIONAL THERMAL POWER STATION

SINGRAULI , MADHYA PRADESH

Submitted By:

Rishikesh (11-1-6-002)

NIT, Silchar

In this Presentation

1. Introduction

2. Power plant layout

3. Coal to Electricity Basics

4. Main and Auxiliary Equipments .

5. Combustion Process

6. Power Plant Cycle

7. Boilers.

8. Burner Management System

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.

General Layout of Thermal Power

Station

Diagram of a typical coal-fired

thermal power station

1. Cooling tower 10. Steam Control valve 19. Superheater

2. Cooling water pump11. High pressure steam

turbine

20. Forced draught

(draft) fan

3. transmission line (3-

phase)12. Deaerator 21. Reheater

4. Step-

up transformer (3-

phase)

13. Feed water heater22. Combustion air

intake

5. Electrical

generator (3-phase)14. Coal conveyor 23. Economiser

6. Low pressure steam

turbine15. Coal hopper 24. Air preheater

7. Condensate pump 16. Coal pulveriser 25. Precipitator

8. Surface condenser 17. Boiler steam drum26. Induced draught

(draft) fan

9. Intermediate

pressure steam turbine18. Bottom ash hopper 27. Flue gas stack

Coal to Electricity ….. Basics

Coal

Chemical Energy

Super Heated Steam

Pollutants

Thermal Energy

Turbine Torque

Heat Loss

In

Condenser

Kinetic Energy

Electrical Energy

Alternating current in Stator

Mech. Energy

LossASHHeat

Loss

Elet. Energy

Loss

Main and Auxiliary e q u i p m e n t s

1. Coal handling plant

2. Pulverizing plant

3. Draft fans

4. Boiler

5. Ash handling plant

6. Turbine

7. Condenser

8. Cooling towers and ponds

9. Economiser

10. Superheater and Reheater

11. Air preheater

Coal handling plant and Pulverizing Plant

•The function of coal handling plant is automatic

feeding of coal to the boiler furnace.

• A thermal power plant burns enormous amounts

of coal.

•Coal is conveyed through rail wagon from out side

of plant

•Through conveyor system collected in hopper and

ground to a very fine powder by large metal

spheres in the pulverized fuel mill.

•Pulverizing is a means of exposing a large surface

area to the action of oxygen and consequently

helping combustion.

•A 200MW plant may require around 2000 tons of

coal daily

Draft system

The circulation of air is caused by a difference in

pressure, known as Draft.

Forced Draft fan use to feed pulverized coal to

boiler

Induced Draft fan use to maintain the flow of flue

gases in the boiler.

Forced Draft FanInduced Draft Fan

Boiler

• A boiler or steam generator is a closed

vessel in which water under pressure, is

converted into steam.

• It is one of the major components of a

thermal power plant

• Always designed to absorb maximum

amount of heat released in the process of

combustion

Boilers are of two types-

1. Fire tube boiler

2. Water tube boiler

Superheater and Reheater

Superheater is a device used to convert saturated steam or

wet steam into dry steam.

Output steam is called Superheated steam and the

temperature is 540 Celsius.

Superheated steam used to rotate HP turbine.

Some of the heat of superheated steam is used to rotate

the turbine where it loses some of its energy.

Reheated is added a heat to that steam.

The steam after reheating is used to rotate the second

steam turbine where the heat is converted to mechanical

energy.

BOILER FEED PUMP Feed deoxygenated water to the boiler drum through economizer.

SOLE PLATE

(BASE PLATE)

SLEEVE

DE BEARING

DE BEARING

DE AREATOR

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.

The condensed water is then passed by a feed pump through a deaerater.

Turbine

A steam turbine is a mechanical device that extracts thermal

energy from pressurized steam, and converts it into rotary motion.

Ash handling plant

The percentage of ash in coal varies from 5% in good quality

coal to about 40% in poor quality coal

Power plants generally use poor quality of coal , thus amount of

ash produced by it is pretty large

A modern 2000MW plant produces about 5000 tons of ash daily

CONDENSER

Water Cooled Condenser Air Cooled 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.

HPH 5

PSH

E

C

O

HPH6

FSHLTSHDRUM

F

U

R

N

A

C

E

IPT LPTHPT

R/H

LPH 1

GSC

LPH2LPH3DEA D/C

COND

CONDENSATE CYCLE

Cooling towers and pondso A condenser needs huge quantity of water to condense the steam .

o Typically a 2000MW plant needs about 1500MGallon of water.

o Most plants use a closed cooling system where warm water coming from condenser is cooled

and reused

o Small plants use spray ponds and medium and large plants use cooling towers.

o Cooling tower is a steel or concrete hyperbolic structure having a reservoir at the base for

storage of cooled water

o Height of the cooling tower may be 150 m or so and diameter at the base is 150 m

Economiser

Economizer are mechanical devices intended to reduce energy consumption, or to

perform another useful function like preheating a fluid.

Flue gases coming out of the boiler carry lot of heat. An economiser extracts a part of

this heat from flue gases and uses it for heating feed water.

This use of economiser results in saving coal consumption and higher boiler efficiency

Air preheater

After flue gases leave economiser, 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

Rankine Cycle

Adiabatic Expansion in

Turbine

Constant Pressure Heat

Rejection in Condenser

Pump Work

Sensible heat Addition in

Economizer

ENTROPY

T

E

M

P

E

R

A

T

U

R

E

Latent Heat Addition in

Evaporator (constt. Pressure) Super Heating

L + V

Boiler

Boiler Temperature Measurement

Expansion of Solids

Thermostats

Expansion of Liquids

Temperature Gauges

Expansion of gases

Temperature Gauges

Thermal Electricity Thermocouples

Type K Chromel Alumel etc.

Change of Electric Resistance (RTD)

Pt100

Cu53

Intensity of total radiation

Optical Pyrometer

Radiation Pyrometer

Burner management system

Burner management system is designed to ensure the execution of

a safe ,orderly operating sequence in the startup and shutdown of

fuel firing equipments and to prevent errors of omission safe

operating procedure.

Function of BMS TO PROVIDE SAFETY TO BOILER.

TO PROVIDE ORDERLY SEQUENCE IN THE S/U & S/D OF FUEL FIRING EQUIPMENTS.

CONTINUOUS FLAME MONITORING.

MAINTAIN THE APPROPRIATE TEMPERATION AND AIR PRESSURE INSIDE THE BURNER

Prevent firing unless a satisfactory furnace purge has first been completed.

THANK YOU