1. Prepared By, Akhil S Electrical & Electronics Engg. MACE
2. Introduction Works on Rankine Cycle Steam produced in boiler (usually by burning coal) is expanded in the prime mover (ie; steam turbine) Condensed steam is fed back to boiler again The steam turbine drives the alternator produces electricity Steam power plants contribute about 65% of total electrical energy generated in India
3. Rankine Cycle
4. Layout of Steam Power Plant The schematic arrangement of a modern steam power station can be divided into the following stages: Coal and ash handling plant Steam generating plant Steam turbine Alternator Feed water Cooling arrangement
5. Coal and Ash handling plant Coal is transported to power station by rail or road and stored in coal storage plant and then pulverised Pulverised coal is fed to fed to the boiler by belt conveyers Coal gets burned in the boiler and ash produced is removed to the ash handling plant and then delivered to ash storage plant for disposal A 100MW station operating at 50% LF may burn about 20000tons of coal per month and produce 3000 tons of ash
6. Coal handling plant • Wagon unloading system • Crushing system • Conveying system Coal handling plant section
7. ASH HANDLING PLANT The Ash from the boiler is collected in two forms: 1. Bottom Ash(Slurry):It’s a waste which is dumped into a Ash Pond 2. Fly ash: Fly ash is separated from Flue Gases in ESP(Electro static Precipitator). Fly Ash & Flue Gases Economizer ESP Bottom ash(wet ash) Ash Pond Boiler Cylo Chimney Fly ash Flue Gases Cement Factory
8. Steam generating plant The steam generating plant consists of a boiler for the production of steam and other auxiliary equipment for the utilization of flue gases 1) Boiler: The heat of combustion in the boiler is utilized to convert water into steam at high temperature and pressure
9. Boiler at Kota Thermal Power Station
10. Steam generating plant 2) Superheater: The steam produced in boiler is wet and is passed through a superheater where it is dried and superheated. Increases efficiency
11. Steam generating plant 3) Economiser: It’s essentially a feed water heater and derives heat from the flue gases
12. Steam generating plant 4) Air Preheater: Increases the temperature of the air supplied for coal burning by deriving heat from flue gases. Air is drawn from the atmosphere by a forced drought fan and is passed through air preheater before supplying to the boiler furnace.
13. Steam Turbine Dry and superheated steam from superheater is fed to the steam turbine. The heat energy of steam when passing over the blades of turbine is converted into mechanical energy. After giving energy to the turbine, the steam is exhausted to the condenser which condenses the exhausted steam by means of cold water circulation
14. Turbine – Full View
15. Alternator Steam turbine is coupled to an alternator which converts the mechanical energy to electrical energy The electrical output of the alternator is delivered to the bus bars through transformer, circuit breakers and isolators.
16. Feed Water The condensate from the condenser is used as feed water to the boiler. The water that may be lost in the cycle is made up from the external source The feed water on its way to boiler gets heated up by water heaters and economiser. This helps to improve the overall efficiency of the plant
17. Raw Water Purified DM water For cooling purpose Steam Conden ser Water in a Power Plant is used for 1.Production of Steam- for rotating turbine. 2.Cooling Purpose- For cooling of various equipment 3% of water is wasted during this process. Appx 4 cubic mt water is lost /day/MW
18. Cooling Arrangement Condenser condenses the steam exhausted from the turbine Water is drawn from natural sources like river, lake, canals… Circulating water takes up the heat and itself gets heated up This hot water can be discharged away or used again by using a cooling tower
19. Reference Principles of Power System- V.K. Mehta A Course in Power Systems- J.B. Gupta