How thermal power plant works is a good question. In this topic, we discuss about the working procedure of thermal power plant.
Thermal power plant is operates on the Rankine Cycle. Coal burns in the boiler. Due to which water converts into steam. The steam expand in a turbine, which produces mechanical power. Due to which mechanical power drives the alternator couples with it. The steam after expansion in turbine is condense in a condenser. Moreover, which fed into the boiler again.
Main circuits of thermal power plant
The main circuits of thermal power plants can be divide into four parts
Fuel and Ash Circuit
coal is deliver from the supply points to the storage site by road, rail or water boats. By road, coal is transport in trucks. However, for small stations such inland transport may be enough. Power plants are close to waterway, Such as canal, river or sea transportation by boat or ship may quite effective. However in more cases transportation of coal by rail, road is the most common.
In case of small power, station the coal quantity being small. Manual unloading from rail car may be use but for large power stations the unloading from the railway, siding done with the help of wagon tipplers. However the coal convey to the coal handling plant. Coal handling plant the coal burn into the boiler. Thus, the coal burns and complete our requirement. Those ashes after complete combustion of fuel collects at the back of the boiler and is remove to the ash storage by means of scrap conveyors.
Air and Fuel Gas Circuit
Air is drown down from the open atmosphere by force of drought fans. In which the heat of flue gases boiler tubes heats it. Moreover, super heated tubes is draw by induced drought fan. Through dust collector economizer and air pre-heater and finally exhausted to the atmosphere through chimney.
Fixed Water Steam Circuit
- the condensed water is exhaust from the condenser using condensate pump. Which then force to feed water heater. Where the temperature raised by the heat from bled steam. The feed water is pump to high-pressure water heater. Moreover the pump water gets heated by the bled of steam extracted at suitable point of steam turbine.
It is then pump into boiler through economizer, in which it is further heated by flue gases. In boiler, water is convert into high power steam, which is wet. Wet stream is pass through super heated, where it is dried and further super heated. Finally, it is supply towards the main valve.
Cooling Water Circuit
Cooling water circuit is supply from a natural source such as river, canal or see. The water is pass through screens to remove the matter, which might choke the condenser tube. It is circulate through the condenser for condensing the seam and finally discharge to the suitable position neat the supply source. During the passage, its temperature raises and in case of cooling towers the heat must be extract before the water is again pump to condenser. The circulation of cooling water to the condenser help in maintain low pressure in a condenser.