Utilizing exergy analysis in studying the performance of steam power plant at two different operation mode

Abstract

This paper presents the exergy analysis for a 650 MW thermal power plant. The relationship between power plant exergy and thermal efficiencies is being presented for two different loads. Moreover, the effect of the decreasing condenser pressure, IPT inlet pressure and increasing S/H steam temperature inlet to both HPT and IPT is studied. The exergy analysis shows that the maximum source of exergy destruction is the boiler, followed by the turbine, then the condenser. Also, it is found that 0.5725% of the power can be saved at full load and by 0.5878% at half load if the condenser pressure is decreased from 0.067 bar to 0.049. Decreasing IPT inlet pressure by 4.5 bar will save power by 0.709% at full load and 1.394% at half load. When S/H steam temperature inlets to HPT are increased by 45 °C. The power is saved by 10.383% and 8.906% at full load and half load respectively. Also, increasing S/H steam temperature inlets to IPT by 45 °C will save power by 7.285% at full load, compared with 6.736% at half load. Moreover, increasing both inlets to HPT and IPT by 45 °C will save power by 17.67% and 15.64% at full and half loads.