Thermal power plant

Submitted by= NIRBHAYA VIKASROLL.NO. =11EBKEE068

introduction Operation MECHANISM Plant layout Coal handling plant Boiler Turbine Turbo-generator transformer Ash Handling Plant

NTPC is the largest thermal power generating company of India.

ntpc is a public sector company, it was incorporated in the year1975 to accelerate power development in the country

NTPC has installed capacity of 43,128 MW. It plans to be a 75,000MW company by 2017.

The coal is brought and crushed to powder. This is feed to Boiler forproducing heat.

In Boiler the water is converted to steam.

In Super heater the moisture content is removed from the steam and thatsteam 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 theIntermediate 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 ElectricPower.

The power generated is then Transmitted.

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.

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.

Rejected- The stones and

unwanted coal is rejected

Secondary Crusher- The fine pieces of coal is crushed to powder (to 25mm grit)

Junction Tower

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.

BOILER

Stacker & Reclaimer-It is used to store the powdered coal for emergency purpose

Atmospheric air (Through FD fan)

Two way conveyor

Specification Wagon Tripler Coal feed to plant

H.P. 75 HP 150 HP

Speed 1480 rpm 1480 rpm

Voltage 415 V 415 V

Type Induction Induction

A boiler or steam generator is a closed vessel in which waterunder 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 inthe process of combustion.

Mainly two types of boilers used in thermal power plant.1. Fire tube boiler2. Water tube boiler

Super heater

Re-heater

Air Preheater

Economizer

Draft system & Fans

A super heater is a device used to convert saturated steam into drysteam

They are the same as the super-heaters but as their exittemperature is a little bite less than super-heaters and theirpressure is 20%-25% less than the super-heater.

The function of the air pre-heater is to increase thetemperature of air before it enters the furnace. It is generallyplaced after the economizer.

An economizer is a device in which the waste heat of the flue gasesis utilized for heating the feed water.

A steam turbine is a device that extracts thermal energy from pressurized steamand uses it to do mechanical work on a rotating shaft.

Steam Turbine is of two types:

1. Impulse Turbine

2. Reaction Turbine

In a Thermal Power Plant generally 3 turbines are used to increase the efficiency.

1. High Pressure Turbine(HPT): The superheated steam is directly fed to this turbineto rotate it.

2. Intermediate Pressure Turbine(IPT): The out put from the HPT is reheated in RHand used to rotate IPT .

3. Low Pressure Turbine(LPT): The Exhausted steam from the IPT is directly fed toIPT and rotate the shaft of LPT.

The transformation of mechanical energy into electrical energy iscarried out by the turbo-Generator in coal fired thermal power plant.

S. No. Parameter Values

1 KW ratings 210 MW 95 MW2 KVA Rating 2,47,000 KVA 1,17,500 KVA 3 Power Factor 0.85 0.854 Phase 3 35 Rated Speed 3000 rpm 3000 rpm6 Rated Frequency 50 Hz 50 Hz7 Stator Current 9050 A 6475 A 8 Stator Voltage 15.75 KV 10.50 KV9 Rotor Current 2600 A -

10 Rotor Voltage 310 KV -

Transformers used in thermal power plant are as follows:-

1. Generating Transformer(500 MVA)

2. Station Transformer(40 MVA)

3. Unit auxiliary transformer(16 MVA)

4. Excitation transformer (25 MVA)

5. Current transformer

6. Voltage transformer

In Thermal Power Plant’s coal is generally used as fuel and hencethe ash is produced as the byproduct of Combustion. Ash generatedin power plant is about 30-40% of total coal consumption andhence the system is required to handle Ash for its proper utilization

Fly Ash- Ash generated in the ESP which got carried out with theflue gas is generally called Fly ash. It also consists of Air preheater ash & Economizer ash. Around 80% is the value of fly ashgenerated.

Bottom ash- Ash generated below furnace of the steamgenerator is called the bottom ash. Bottom ash is 20% of the ashgenerated in coal based power stations.

Switch Yard

IsolatorThese are used to disconnection transmission line under

no-load condition for safety, isolation and maintenance

CURRENT TRANSFORMER

These are used to step-down currents for measurement, control & protection

These are used for automatic switching during normal or abnormal conditions . There are sf6 circuit breaker is used.

CIRCUIT BREAKER

LIGHTING ARRESTERSThese are used to discharge lightning over voltages and switching over voltages to earth.

CONCLUSION

In thermal power plant heat energy of coal is used to make steam and this steam generate mechanical energy and this mechanical energy convert in to electrical energy with help of generator.

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