Improving the Performance of Steam Power Plant by Applying Energy and Exergy Analysis at Altering Operating Parameters

Abstract

This study presents the energy and exergy analysis for unit three of the Al-Mosyab thermal power plant, which has a capacity of 225 MW. The energy losses, exergy destruction and second law efficiency, are computed. The objective is to obtain a comprehensive prediction of improvement that will happen in the performance. Results showed that the second law efficiency of the cycle is 34.91%, and the maximum exergy destruction was at the boiler by 86%. The plant's second law efficiency improves successfully to 37.65%, and 0.67 kg/s of the fuel mass flow rate can be saved. As well as, the total exergy destruction decreased by 10.8% at increasing the feedwater temperature to 230 °C. The second law efficiency has enhanced to 35.74% and 1.32% of the exergy destruction drops when reducing the mass flow rate of the desuperheater spray water of the main steam. The second law efficiency increased by 2.27%, and 1.25% of the total exergy destruction was reduced when the hot reheat pressure increased. Moreover, the analysis reveals that the plant's second law efficiency has grown by 6.45% and that the total exergy destruction has fallen by 3.31% when cold reheat steam temperature is reduced.