Improving the efficiency of Thermal power Stations
The thermal efficiency of a steam power plant can be increased by the following ways:
1. The thermal efficiency can be increased by raising the initial temperature of the steam without changing the pressure.
2. An increase in the initial pressure of steam raises the thermal efficiency.
3. Intermediate reheating of steam improves the thermal efficiency of steam power plant but the initial pressure of steam improves the thermal efficiency of steam power plant but the wetness fraction of such steam also grows at the end of expansion. The wetness is so high that it causes wear of the blades of the last stages of a steam turbine. This short coming is eliminated b intermediate reheating of the steam. The steam from boiler after partial expansion in the first stage turbine is fed into super heater, where it is reheated at a constant pressure either to the temperature of live steam or to a temperature slightly below that one. The reheated steam then flows to the last stages of the turbine where the process of expansion is completed. The schematic diagram is as show in
4. Thermal efficiency of steam power plant can be improved by carrying out regenerative heating of the feed water. Such heating of the water is carried out b using the heat of steam partly tapped from the turbine. In this method the steam from boiler flows into steam turbine. After partial expansion some of the steam is tapped from the first stage of the turbine and directed to feed water heated and then to feed tank. The other part of steam condenser. The condensate is delivered by pump to feed tank. Working of thermal power plant is input is coal and output is electrical energy. Steam energy is rotating to the turbine then automatic turbine is rotating to generator. Finally steam energy is converted into electrical energy.
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