Steam Power Plant Components, Diagram of Steam Power Plant , Working Of Steam Power Plant
Components Of Steam Power Plants :
A steam power plant must have following equipment :
(a) A furnace to burn the fuel.
(b) Steam generator or boiler containing water. Heat generated in the furnace is utilized to convert water into steam.
(c) Main power unit such as an engine or turbine to use the heat energy of steam and perform work.
(d) Piping system to convey steam and water.
In addition to the above equipment the plant requires various auxiliaries and accessories depending upon the availability of water, fuel and the service for which the plant is intended.
The flow sheet of a thermal power plant consists of the following four main circuits :
(a) Feed water and steam flow circuit.
(b) Coal and ash circuit.
(c) Air and gas circuit.
(d) Cooling water circuit.
A steam power plant using steam as working substance works basically on Rankine cycle.
Steam is generated in a boiler, expanded in the prime mover and condensed in the condenser and fed into the boiler again.
The different types of systems and components used in steam power plant are as follows :
(a) High pressure boiler
(b) Prime mover
(c) Condensers and cooling towers
(d) Coal handling system
(e) Ash and dust handling system
(f) Draught system
(g) Feed water purification plant
(h) Pumping system
(i) Air preheater, economizer, super heater, feed heaters.
Diagram Of Steam Power Plants :
Figure shows a schematic arrangement of equipment of a steam power station. Coal received in coal storage yard of power station is transferred in the furnace by coal handling unit. Heat produced due to burning of coal is utilized in converting water contained in boiler drum into steam at suitable pressure and temperature. The steam generated is passed through the superheater. Super-heated steam then flows through the turbine. After doing work in the turbine the pressure of steam is reduced. Steam leaving the turbine passes through the condenser which is maintained the low pressure of steam at the exhaust of turbine. Steam pressure in the condenser depends upon flow rate and temperature of cooling water and on effectiveness of air removal equipment. Water circulating through the condenser may be taken from the various sources such as river, lake or sea. If sufficient quantity of water is not available the hot water coming out of the condenser may be cooled in cooling towers and circulated again through the condenser. Bled steam taken from the turbine at suitable extraction points is sent to low pressure and high pressure water heaters.
Air taken from the atmosphere is first passed through the air pre-heater, where it is heated by flue gases. The hot air then passes through the furnace. The flue gases after passing over boiler and superheater tubes, flow through the dust collector and then through economiser, air pre-heater and finally they are exhausted to the atmosphere through the chimney.
Steam condensing system consists of the following :