Energetic and exergetic analysis of a multi-stage turbine, coal-fired 173 MW power plant

This paper reports the results of an energy and exergy audit of a 173 MW pulverised coal fired, subcritical steam power plant unit in the Midwestern USA. Energy and exergy analysis determined the thermal efficiency and identified the greatest sources of irreversibilities and also mapped the flow of energy and exergy throughout the plant. The overall plant energetic and exergetic efficiencies were found to be 32.8% and 33.7%, respectively. The largest source of exergy destruction in the cycle was found to be within the steam generator. Options explored to increase the exergetic efficiency were to improve the steam turbines to operate with higher temperature steam, to bring water into the condenser from the lake that is closer to the ambient temperature, and to replace a valve after the boiler feedwater pump with a hydro-turbine to produce some power.