Powerplant

PRESENTED BYBIBIN BABY

A power station (also referred to as agenerating station, power plant, powerhouseor generating plant) is an industrial facility forthe generation of electric power

On the basis of source of energy

Nuclear power plant

Geothermal power plant

Fossil Fuel Power plant

Solar Thermal Power plant

Hydroelectric power plant

A steam power plantconverts the chemicalenergy of the fossilfuels(coal,oil,gas) intomechanical/electricalenergy

Coal and Ash Circuit Coal arrives at the storage yard

After necessary handling

Passes on to the furnaces through fuel feeddevice

Ash resulting from combustion of coal collectsat the back of the boiler

Ash is removed to ash storage yard throughash handling equipment

Air is taken in from atmosphere through theaction of a forced or induced draught fan

It is passed on to furnace through air preheaterwhere it is heated by flue gases and passed toboiler

Flue gases after passing around boiler tubesand super heater tubes in the furnace passthrough a dust catching device exit throughchimney after passing through economiser andpreheater

Condensate leaving the condenser is firstheated in a closed feed water heater throughextracted steam from lowest pressureextraction point of turbine

It then passes through several water heatersbefore going to boiler through economiser

In boiler drum and tubes, water circulates dueto difference between the density of water inlower temp and higher temperature sections ofboiler

Wet steam from drum is further heated up in thesuperheater before being supplied to theprimeover

After expanding in high pressure turbine steam istaken to the reheat boiler and brought to itsoriginal dryness or super heat before being passedon to low pressure turbine

It is exhausted through the condenser to hot well

A part of steam and water is lost while passingthrough components it is comepensated bysupplying additional feed water

The cooling water supply to condenser helpson maintaining a low pressure in it

The water may be taken from a natural sourcesuch as river,lake or sea

Same water maybe recirculated again aftersome cooling

Reliability

Minimum capital cost

Minimum operating and maintenance cost

Capacity to meet peak load effectively

Minimum losses of energy in transmission

Low cost of energy supplied to the consumers

Reserve capacity to meet future demands

Nuclear power plant uses nuclear energy to

make steam and produce electricity

A controlled fission heat source

A coolant system to remove and transfer theheat produced

Equipment to convert the thermal energycontained in hot coolant to electric power

Fission is the process that occurs when aneutron collides with nucleus of certain of theheavy atoms causing the original nucleus splitsinto two or more unequal fragments whichcarry off most of the energy of fission as kineticenergy.

A nuclear reactor is anapparatus in whichnuclear fission isproduced in the formof a controlled selfsustaining chainreaction

Fuel: Uranium is the basic fuel. Usually pelletsof uranium oxide (UO2) are arranged in tubesto form fuel rods. The rods are arranged intofuel assemblies in the reactor core.

Plutonium 239 is also used as fuelModerator:Material in the core which slowsdown the neutrons released from fission so thatthey cause more fission. It is usually water, butmay be heavy water or graphite.

Control rods. These are made with neutron-absorbing material such as cadmium, hafniumor boron, and are inserted or withdrawn fromthe core to control the rate of reaction, or to haltit.

In fission, most of the neutrons are releasedpromptly, but some are delayed. These arecrucial in enabling a chain reacting system (orreactor) to be controllable and to be able to beheld precisely critical.

Coolant. A fluid circulating through the core soas to transfer the heat from it. Usually water isused as coolant.

CO2 is also used

Pressure vessel or pressure tubes. Usually arobust steel vessel containing the reactor coreand moderator/coolant, but it may be a seriesof tubes holding the fuel and conveying thecoolant through the surrounding moderator.

Steam generator: These are large heat exchangersfor transferring heat from one fluid to anotherwhere the high-pressure primary coolant bringingheat from the reactor is used to make steam for theturbine, in a secondary circuit

Containment: The structure around the reactorand associated steam generators which is designedto protect it from outside intrusion and to protectthose outside from the effects of radiation in caseof any serious malfunction inside. It is typically ametre-thick concrete and steel structure.

Needs lesser space compared to otherconventional power plants

Well suited to meet large power demands

Saving in cost of fuel transportation

Operation is more reliable

Not affected by adverse weather conditions

Expenditure on metal structures piping,storagemechanisms is much lower for a nuclearpowerplant compared to steam plant

Capital cost is high

Danger of radioactivity

Cannot be operated at varying load efficiently

Maintenance cost is high

Disposal of fission products is a big problem

Affects health of workers