Ehsan Eshghi - PhD Student in Mechanical Engineering, Applied Design, Islamic Azad University, Marvdasht Branch,Fars, Iran

This study carried out energy and exergy analyses of a thermal power plant in order to evaluate the energetic and exergetic efficiencies and irreversibilities of units, sections and the overall system. It was also, to determine the optimum fuel-air ratio and optimum combustion temperature at different throughputs. The thermal plant consisting of ۲۳ units and ۴ sections was simulated using HYSYS simulation software and EXCEL spreadsheet. The EXCEL spreadsheet was used for the energy and exergy analyses. It was found that throughput did not influence the energy efficiencies of the units but the exergy efficiencies. Throughput did not influence the energy and exergy efficiencies of the sections. The overall energetic efficiencies of the plant were ۱۸.۱۷, ۱۹.۷۹, ۲۱.۴۲, and ۲۱.۴۵% and the overall exergetic efficiencies were ۱۰.۲۶, ۱۱.۲۲, ۱۱.۵۸, and ۱۱.۶۱% for throughputs of ۵۰, ۷۵, ۱۰۰ and ۱۱۰%, respectively. The overall irreversibilities of the plant increased as the throughput increased. The optimum fuel-to-air ratio which gave the optimum combustion temperature in the furnace was found to be ۱:۱۲.۶ for all the throughputs which was an improvement over the current practice of ۱:۱۹.۸. Throughput did not influence the maximum combustion temperature in the furnace

Thermal Power Plant, Exergy, Energy, Efficiency, Irreversibility, Units and Sections.