Coal power plant


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Coal power plant

  3. 3. INTRODUCTION1.COALCoal is classified as fossil fuel, and itis the main energy source for electricityproduction in the world. This howeveralso means that coal is the main sourceof carbon emissions in the world meaning that coal significantlycontributes to climate change issue. Coal is composed primarily ofcarbon along with variable quantities of other elements, mostlysulphur, hydrogen, oxygen and nitrogen.
  4. 4. 2.POWER PLANTMechanical Energy Electrical EnergyA power station (also referred to as a generating station, powerplant,powerhouse or generating plant) is an industrial facility forthe generation of electric power. At the center of nearly all powerstations is a generator, a rotating machine that convertsmechanical power into electric power by creating relative motionbetween a magnetic field and a conductor. Most power stations inthe world burn fossil fuel such as coal,oil, and natural gas togenerate electricity, and some use nuclear power, but there is anincreasing use of cleaner renewable sources such as solar, wind,wave and hydroelectric. Central power stations produce AC power,after a brief Battle of Current in the 19th century demonstrated theadvantages of AC distribution.
  5. 5. Thermal Power Plant:“A thermal power plant is a power plant in which theprime mover is stream. Water is heated, turns intosteam and spins a turbine which drives an electricalgenerator. After it passes through the turbine, thesteam is condensed in a condenser and recycled towhere it was heated, this is known as a Rankine cycle.
  6. 6. PARTS1.Coal ConveyorCoal conveyor is a belt type arrangement that are used to move coal efficiently.2.PulverizerPulverizer increases the coal combustion efiiciency of coal.3.Boiler (Furnace)A boiler is a device used to create steam by applying heat energy to water.4.SuperheaterIn a power plant, after the steam is conditioned by the drying equipment insidethe steam drum, it is piped from the upper drum area into tubes inside an area ofthe furnace known as the super heater.5.EconomizerEconomizer are mechanical devices intended to reduce energy consumption, or toperform another useful function like preheating a fluid.
  7. 7. 6.ReheatorReheator added heat in the high-pressure steam.7.Steam TurbineA steam turbine is a mechanical device that extracts thermal energy frompressurized steam, and converts it into rotary motion.8.GeneratorA device which convert mechanical energy into electrical energy is called generator.9.CondenserCondenser is a device or unit used to condense a substance from its gaseous to itsliquid state, typically by cooling it.10.DeaeratorA deaerator is a device that is widely used for the removal of air and other dissolvedgases from the feed water to steam-generating boiler.
  9. 9. FUNCTIONSTAGE 1 Coal arriving by train can be stocked for later use or taken straight to the coalbunkers. Coal is prepared for use by crushing the rough coal to pieces less than 2 inch(5 cm in size). Crushing the coal into a fine powder makes easirer to burn itmore completely. Coal mills grind the larger of 2 inch pieces to face powder and mixed them withprimary combustion air which transports the coal to the furnace and preheatsthe coal to drive off excess moisture content. By pulverizing the coal combustion efficiency of coal increases.Conveyor Pulverized mill
  10. 10. STAGE 2 Pulverized coal is burnt to produce steam. Water from the feed pump, after pre-heatingenters the boiler. This water may be obtainedfrom a nearby river or lake. The condensed waterfrom the cooling tower is re-used. The heated or vapourized fluid exits the boiler for use invarious processes and heating applications.
  11. 11. STAGE 3 The steam produced in the boiler,goes to the steam drum and is thenpiped to super-heaters where it isheated above saturation temperature. At this point steam is now turned intoa very powerful source of energy. This rotates the turbine.
  12. 12. STAGE 4 Flue gases coming out of the boiler carrya lot of heat. An economizer extracts apart of this heat from flue gases and useit for heating feed water. This use of economizer result in savingcoal consumption and higher boilerefficiency.
  13. 13. STAGE 5 Reheaters is also a steam boiler in which heat is added to thishigh-pressure steam. Which has given up some of its energy inexpansion through the intermediate-pressure turbine. The steam after reheating is used to rotate the the second steamturbine where the heat is converted to mechanical energy. This mechanical energy is used to run the generator, which iscoupled to the turbine, there by generating electrical energy.
  14. 14. STAGE 6The turbine generator consists of a series of steam turbinesinterconnected to each other and a generator on a common shaft. There is a high pressure at one end , follower by an intermediate pressureturbine. A low pressure turbines, and the generator. As steam moves through the system, it losses pressure and thermal energyand expands in volume, requiring increasing diameter and longer blades ateach succeeding to extract the remaining energy.
  15. 15. STAGE 7 Steam after rotating steam turbine comes to the condenser. The purpose of condenser is to condense the outlet steam fromsteam turbine to get the condensed steam in the form of purewater. This water is then pumped back to boiler.
  16. 16. STAGE 8 A steam generating boiler requires that the boiler feed watershould be devoid of air and other dissolved gases,particularlycorrosive ones. In order to avoid corrosion of the metal power station uses aDeaerator, for the removal of air and other dissolved gasesfrom the boiler feed water. A deaerator has a vertical. Domed deaeration sectionmounted on top of a horizontal cylindrical vessel which sevesas a deaerated boiler feed water storage tank.
  17. 17. STAGE 9 The enormous pressure of the steam pushing against a seriesof giant turbine blades turns the turbine shaft. The turbineshaft is connected to the shaft of the generator, where magnetsspin within wire coils to produce electricity. Electricity is send through power grid lines and then travelledto substations located in towns.
  18. 18. ADVANTAGESCoal is a fossil fuel like oil and gas. Fossil fuels are all formedout of organic matter deposited, decomposed and compressed,storing all the carbon involved under the earths surface formillions of years.Some advantages are as follows:o Easily combustible, and burns at low temperatures, makingcoal-fired boilers cheaper and simpler than many others.o Widely and easily distributed all over the world.o Comparatively inexpensive to buy on the open market due tolarge reserves and easy accessibility.o Good availability for much of the world (i.e. coal is found manymore places than other fossil fuels).
  19. 19. o Most coal is rather simple to mine, making it by far the leastexpensive fossil fuel to actually obtain.o Coal-powered generation scales well, making it economicallypossible to build a wide variety of sizes of generation plants.o A fossil-fuelled power station can be built almost anywhere, solong as you can get large quantities of fuel to it. Most coal firedpower stations have dedicated rail links to supply the coal.o Very large amounts of electricity can be generated in one placeusing coal, fairly cheaply.
  20. 20. DISADVANTAGES:Some disadvantages of coal are:o It is Non-renewable and fast depleting.o Coal has the lowest energy density of any fossil fuel - that is, itproduces the least energy per ton of fuel.o It also has the lowest energy density per unit volume, meaningthat the amount of energy generated per cubic meter is lowerthan any other fossil fuel.o high coal transportation costs due to the bulk of coal (as aresult of the preceding two low energy density problems),especially for countries with no coal resources and hence willrequire special harbours for coal import and storage.o Coal dust is an extreme explosion hazard, so transportationand storage must take special precautions to mitigate thisdanger.o Coal storage cost is high especially if required to have enoughstock for few years to assure power production availability.
  21. 21. o Burning fossil fuels releases carbon dioxide, a powerful greenhouse gas, that had been stored in the earth for millions ofyears, contributing to global warming.o Mining of coal leads to irreversible damage to the adjoiningenvironment.