The Influence of Throughput on Thermodynamic Efficiencies of a Thermal Power Plant

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 sys tem. It was also, to determine the optimu m fuel-air rat io and optimu m co mbustion temperature at different throughputs. The thermal p lant consisting of 23 units and 4 sections was simulated using HYSYS simu lation 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 p lant were 18.17, 19.79, 21.42, and 21.45% and the overall exergetic efficiencies were 10.26, 11.22, 11.58, and 11.61% for throughputs of 50, 75, 100 and 110%, respectively. The overall irreversibilities of the plant increased as the throughput increased. The optimu m fuel-to-air ratio which gave the optimu m co mbustion temperature in the furnace was found to be 1:12.6 for all the throughputs which was an improvement over the current practice of 1:19.8. Throughput did not influence the maximu m co mbustion temperature in the fu rnace.