Evaluation of a heat recovery steam cycle based on energy, exergy, environmental and economic analyses

Abstract

In this study, the waste heat from the chimneys of a cement factory was recovered by a steam cycle for power generation. The performance of the cycle was evaluated by a 4E analysis for both configurations with a feed water heater (FWH) (case A) and without FWH (case B). The results indicated that the efficiency of the cycle was decreased by installing FWH. The maximum energy and exergy efficiencies occurred when the pressure of boiler for configurations A and B were 830 kPa and 913 kPa, respectively while considering the economic analysis, the best performance occurred when the boiler pressure of each configuration were 1,049 kPa and 1,200 kPa, respectively. Furthermore, both configurations were investigated by presenting a novel 4E objective function (4EF). For configurations A and B, general efficient pressure (GEP) was found, which were 1,148 kPa and 1,368 kPa, respectively. Also, the effects of the pinch point temperature difference were analysed.