NTPC- The Power Giant

It is the largest power generating company in INDIA. Established in NOV’ 1975. Has installed capacity of 29,394 MW. It has 15 Coal based, 7 Gas based and 4 Power

Stations in joint ventures. It plans to be a 75000 MW company by 2017. It has diversified into hydro power, coal mining,

power equipment manufacturing, power trading and distribution.

POWER GENERATION AT BADARPUR THERMAL POWER

PLANT• Coal is used to boil the water.• The steam produced is used to spin a turbine.• This turbine drives an electrical generator.

Sr. no. Capacity No. of generators

Total Capacity

1. 210 MW 2 420 MW

2. 95 MW 3 285 MW

Cont.

• There are three main units of the power plant.i. Steam generator or boilerii. Steam turbineiii. Electric generator• Thermal power plant works on the principle

that depend upon the above three units.

COAL HANDLING PLANT

WHAT IS C.H.P

• A coal handling plant is a facility that washes coal of soil and rock.

• Removes the impurities after passing the coal from different stages.

• It is the major part of thermal power plant.• Coal before entering the furnace follows

different stages such as coal handling, sampling, washability, crushing, screening, metal separation.

MAJOR COMPONENTS OF C.H.P

WAGON TIPPLER• Wagons from coal yard come to

the tipplers and are emptied here• The process is performed by slip-

ring motor of rating 55KW,415V,1480RPM.

• This motor turns the wagon by 135 degrees and the coal falls directly on the conveyer belt.

CONVEYER

• There are 14 conveyers in the plant.• They are 1m wide,3cm thick and made of chemically treated vulcanized

rubber and move with speed of 250-300m/min.• Motors employed for conveyers has a capacity of 150hp.• Have a capacity of carrying a coal at the rate of 400 tons per hour.• Few are double belt so that if a belt develops any problem then the

process is not stalled.• It also has a switch after every 25-30m to stop belt in case of emergency.• The max angular elevation of conveyer is designed such that its about 20

degrees.• ZERO SPEED SWITCH- It is a safety device for motors i.e. if belt is not

moving and motor is on then the switch checks the speed of the belt and switches off the motor when speed is zero.

COAL HANDLING

• Coal collected is then passed through the conveyer belt to the large field.

• The coal needs to be stored at these larger fields.

• The field consists of coal, rocks, minerals, contaminations etc.

• Coal handling is the larger part of bulk material handling and is a complex and vital part of CHP.

SAMPLING OF COAL

• It is one of the important part of the process.

• A routine sample is taken at a set frequency.

• A coal sampling consists of samplers, crushers, motors and

feeders.• During wash ability a liberation

process takes place in which physical breakage is required to separate material of different densities.

SCREENING AND SEPARATION

• Screens are used to group process particles into ranges by size.

• Dewatering screen is done which removes water from the product.

• It can be static or mechanically vibrated.

• Screen decks can be made from materials high tensile strength, stainless steel or polyethylene.

MAGNETIC SEPARATION

• It is used to separate any metal pieces from the coal.

• This process takes place before the coal is being sent through the conveyer belt for crushing.

• The capacity of this device is around 50kg.

COAL CRUSHER

• To ensure that the coal is of uniform size it is passed through crusher.

• The crusher is of ring type.• Has a motor rating of 400HP, 606KV.• It is designed to crush the pieces to 20mm size.

PULVERIZER

• Pulverization takes place in two stationary rollers and a power driven boul.

• Its main functions are Drying of coal Grinding Separation of particles of the

desired size• Coal is thus pulverized to

increase its surface exposure thus permitting rapid combustion.

ADVANTAGES OF PULVERIZATION

• It becomes easy to burn wide variety of coal.• Powdered coal has more heating surface area.• High rates of combustion.• Rate of combustion can be adjusted to meet

varying loads.• High temperature can be produced in the

furnace.

Diagram of Coal based thermal power plant•Coal is conveyed in a pulverized fuel mill.•This coal is mixed with pre heated air.•The hot air- fuel mixture is forced at high pressure into boiler where it ignites.•The water flows along the tube lined wall of the boiler.•This water is then turned into steam due to the ignited mixture.•The steam is superheated where its temperature and pressure rapidly increases.

Diagram of Coal based thermal power plant•This steam is then piped to the high pressure turbine.•The three phase turbine process starts.•The steam exhausted is returned to boiler reheater,it is then passed through intermediate and then low pressure turbine.•Now the exiting steam is brought in contact with cold water pumped in from cooling towers inside the condenser.

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