Post 04 - Power Plant Equipments and its Functions

FUNCTIONAL DESCRIPTION

Power Plant 

In Thermal Power Station fuel burns & use the resultant to make the steam, which derives the turbo generator. The Fuel i.e. coal is burnt in pulverized from. The pressure energy of the steam produce is converted into mechanical energy with the help of turbine. The mechanical energy is fed to the generator where the magnet rotate inside a set of stator winding & thus electricity is produced in India 65% of total power is generated by thermal power stations. To understand the working of the Thermal Power Station plant, we can divide the whole process into following parts.

1.         COAL FLOW

In coal fired plants, raw material are air & water in PTPS, coal is transported through Railway wagons from M/s Coal India & is kept reserved on a buffer stock. The brought out to the station is unloaded with the help of wagon tippler. After unloading, the coal is sent to crusher house with the help of conveyor belts. The coal which is now reduced to very small pieces is sent to the coal bunkers with the help of conveyor belt.  The raw coal is fed to coal mills through raw coal feeders raw coal feeders basically regulate raw coal to pulverized coal pipes. A position of the primary air is heated utilizing the heat of the fuel gases & then mixed with the cold air as per requirement by the pulverized coal. Normally the temperature is maintained at 60 to 70 degrees. The coal is now burnt in the furnace using oil in the beginning showered through the nozzles at different elevations in the furnace. To provide air for combustion, the heat of the flue gases also heat it the heat produced due to combustion is utilized for the conversion of water into steam. This water is stored in the boiler drum. There are two sets of pipes attached to the drum, one called riser & other known as down corner through which the water comes to the ring header & steam moves up due to the density difference of water & steam. Its steam is super heated using super heaters & meanwhile the flue gases are through out in the atmosphere through chimney.

              

2.         STEAM FLOW

The super heated steam is sent to the turbine through pipelines there are three turbines in the units, using this steam at different temperature & pressures. After passing through high pressure turbine the steam is send to the reheater for risingthe temperature of the steam. After reheating the steam is sent to the intermediate pressure turbine through reheated line. Here it losses most of its temperature & pressure & finally sent to low pressure turbine. The uses of three different turbines help in increasing the efficiency of the plant. The turbine in turn connecting with a generator produces electricity. Then this electricity is stepped up to grid voltage  with the help of step up transformer & supplied to various sub-stations grids.

Meanwhile, the steam through low pressure (L.P.) Turbine is condensed and the condensed water is stored in hot well.

3.         WATER FLOW

The condensed water is extracted from the hot well through condensate extraction pumps & sent to the boiler drum with the help of BOILER FEED PUMP (B.F.P.) before passing through low pressure heater and dearater. While loss in water is make up from C.S. Tank, which have D.M. Moor in it. The C.S. Tank is directly connected to hot well.

The water used in condenser is sent to cooling tower for cooling. After cooling this water is again sent to condenser with the help of circulating water pump. The loss is making from raw water pump house through clarifier pump house.

RO PLANT

COMPONENTS DESCRIPTION

1.         WAGON TIPPLER:

It is the machine which is used to tip the coal from the wagon. The coal tipped is directly feed to conveyor belt. Its capacity is 12 wagon per hour.

2.         CRUSHER:

            It crushes the coal into small pieces.

3.         COAL MILLS:

In it small pieces of coal are converted into pulverized from. They are 6 in number.

4.         FURNACE:

            It is the chamber in which fuel burns & fire blows.

5.         BOILER DRUM:

            It contains water for boiling.

6.         ELECTROSTATIC PRECIPITATOR:

In this we have electrodes which attract fly ash and extract it from flue gases so that it cannot enter atmosphere.

7.         CHIMENY:

            It is used to release flue gases into the atmosphere.

8.         TURBINE:

Turbine is the part which revolves due to steam pressure. It is of three types.

            a)   High pressure turbine.

            b)  Intermediate pressure turbine.

            c)   Low pressure turbine.

9.         TURBO GENERATOR:

It is the main machine which produces electricity .It is (H₂O) water and H₂ (Hydrogen) gas cooled therefore it is contained in cylindrical chamber.

10.      CONDENSER:

It condenses steam coming from low pressure turbine (L.P.T.) to hot water. By removing air and other non-condensable gases from steam while passing through them.

11.      COOLING WATER (C.W.) PUMP:

            This pump send water from cooling tower to condenser.

12.      COOLING TOWER:

It is used to coal the water its height is near about 143.5 mtrs. The hot water is led to the tower top and falls down through the tower and is broken into small particles while passing over the baffing devices. Air  enters the tower from the bottom and flow upwards. The air vaporizes a small percentage of water, thereby cooling water falls down into tank below the tower from where it is pumped to the condenser and cycle is repeated.

13.      RAW WATER PUMP HOUSE:

            It supplies raw water to the boiler.

14.      CLARIFIER PUMP HOUSE:

The water from raw is clear at clarifier by putting alum in it & filtering it & then supplied to the condenser.

15.      CONDENSATE EXTRACTION PUMP:

C.E.P. pump is used to extract the condense water from the hot well and supply to the deaerator after passing through L.P. heater & Economizer, so that high pressure steam in the cylinder can be created.

16.      LOW PRESSURE HEATER:

It is used to increase the temperature of water, in this way efficiency of system increases.

17.      DEAREATER:

It is used to remove air from water which is entrapped in the water molecules. It is very important part because the entrapped air effect air drum badly.

18.      BOILER FEED PUM (B.F.P.):

It is the heaviest drive in the plant & supply water to boiler drum from dearator.

19.      HIGH PRESSURE HEATER (H.P.):

In this temperature of water increases. Thus efficiency further increases.

20.      ECONOMISER:

In this flue gases exchange heat to the water to increase system  efficiency, causes saving in fuel consumption (5 to 10%). Economizer tubes are made up of steel either smooth or covered with fins to increase the heat transfer surface area.