Energy and exergy analysis of a thermal power plant

Meeting the ever-increasing demand for electric energy poses a challenge for efficient and pollutionfree world as most of the electricity generation is by burning fossil fuels. In order to minimize the environmental impact of the fossil-fuel based electricity generating power plants, it is essential operate these plants efficiently. Efficient operation of power plants requires proper understanding of various losses that take place in the plant. The objective of the present study is to investigate the complete water, steam, air flue gas cycles and main auxiliary equipments of a 150 MW pulverized coal-fired thermal power plant in order to minimize the losses through a comprehensive energy and exergy analyses. The study emphasizes a full investigation of different components and processes of the thermal power plant to create scope for next-level research and power plant development. The study shows that among all the power plant system components, the boiler has the highest exergy destruction of nearly 196 MW due to high irreversibility associated with heat transfer. The boiler is found to have an exergy efficiency of 47.3% and an energy efficiency of 86.1%. The cycle energy and exergy efficiencies are 34.27% and 37.2%, respectively. Thus, the study shows that in order to improve the performance of the power plant it is essential to improve the performance of the boiler significantly. Apart from the improving the boiler efficiency the auxiliary power consumption is minimized by design modification of the demineralized water pump, other cooling water pump, boiler fan and cooling tower fan by retrofitting. After that the saving of water and power consumption are reduced and operating efficiency improved.