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ITRODUCTIO TOTHEMAL POWER PLAT
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Introduction
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Classification
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Functioning
INTRODUCTION
Power Station (also referred to as generating station or power plant) is an industrial facility for the generation of electric power. Power plant is also used to refer to the engine in ships, aircraftand other large vehicles. Some prefer to use the term energy center because it more accuratelydescribes what the plants do, which is the conversion of other forms of energy, like chemicalenergy, gravitational potential energy or heat energy into electrical energy. However, power plant is the most common term in the U.S., while elsewhere power station and power plant are both widely used, power station prevailing in many Commonwealth countries and especially inthe United Kingdom.
A coal-fired Thermal Power Plant
At the center of nearly all power stations is a generator, a rotating machine that convertsmechanical energy into electrical energy by creating relative motion between a magnetic fieldand a conductor. The energy source harnessed to turn the generator varies widely. It dependschiefly on what fuels are easily available and the types of technology that the power companyhas access to.In thermal power stations, mechanical power is produced by a heat engine, which transformsthermal energy, often from combustion of a fuel, into rotational energy. Most thermal power stations produce steam, and these are sometimes called steam power stations. About 80% of allelectric power is generated by use of steam turbines. Not all thermal energy can be transformedto mechanical power, according to the second law of thermodynamics. Therefore, there isalways heat lost to the environment. If this loss is employed as useful heat, for industrial processes or district heating, the power plant is referred to as a cogeneration power plant or CHP(combined heat-and-power) plant. In countries where district heating is common, there arededicated heat plants called heat-only boiler stations. An important class of power stations in theMiddle East uses byproduct heat for desalination of water.
CLASSIFICATION
By fuelBy fuelBy fuelBy fuel
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Nuclear power plants use a nuclear reactor's heat to operate a steam turbine generator.
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Fossil fuelled power plants may also use a steam turbine generator or in the case of natural gas fired plants may use a combustion turbine.
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Geothermal power plants use steam extracted from hot underground rocks.
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Renewable energy plants may be fuelled by waste from sugar cane, municipal solidwaste, landfill methane, or other forms of biomass.
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In integrated steel mills, blast furnace exhaust gas is a low-cost, although low-energy-density, fuel.
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Waste heat from industrial processes is occasionally concentrated enough to use for power generation, usually in a steam boiler and turbine.
By prime moverBy prime moverBy prime moverBy prime mover
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Steam turbine plants use the dynamic pressure generated by expanding steam to turn the blades of a turbine. Almost all large non-hydro plants use this system.
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Gas turbine plants use the dynamic pressure from flowing gases to directly operate theturbine. Natural-gas fuelled turbine plants can start rapidly and so are used to supply"peak" energy during periods of high demand, though at higher cost than base-loaded plants. These may be comparatively small units, and sometimes completely unmanned, being remotely operated. This type was pioneered by the UK, Prince town being theworld's first, commissioned in 1959.
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Combined cycle plants have both a gas turbine fired by natural gas, and a steam boiler and steam turbine which use the exhaust gas from the gas turbine to produce electricity.This greatly increases the overall efficiency of the plant, and many new base load power plants are combined cycle plants fired by natural gas.
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Internal combustion Reciprocating engines are used to provide power for isolatedcommunities and are frequently used for small cogeneration plants. Hospitals, office buildings, industrial plants, and other critical facilities also use them to provide backup power in case of a power outage. These are usually fuelled by diesel oil, heavy oil,natural gas and landfill gas.
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Micro turbines, Sterling engine and internal combustion reciprocating engines are lowcost solutions for using opportunity fuels, such as landfill gas, digester gas from water treatment plants and waste gas from oil production.
FUNCTIONING
Functioning of thermal power plant:Functioning of thermal power plant:Functioning of thermal power plant:Functioning of thermal power plant:
In a thermal power plant, one of coal, oil or natural gas is used to heat the boiler to convert thewater into steam. The steam is used to turn a turbine, which is connected to a generator. Whenthe turbine turns, electricity is generated and given as output by the generator, which is thensupplied to the consumers through high-voltage power lines.
Process of a Thermal Power Plant
Detailed process of power generation in aDetailed process of power generation in aDetailed process of power generation in aDetailed process of power generation in athermal power plant:thermal power plant:thermal power plant:thermal power plant:
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Water intake:
Firstly, water is taken into the boiler through a water source. If water isavailable in a plenty in the region, then the source is an open pond or river. If water is scarce,then it is recycled and the same water is used over and over again.2)
Boiler heating:
The boiler is heated with the help of oil, coal or natural gas. A furnace isused to heat the fuel and supply the heat produced to the boiler. The increase in temperaturehelps in the transformation of water into steam.
