Modeling and analysis of optimal performance of a coal-fired power plant based on exergy evaluation

One of the ways to minimize fossil fuel consumption is to optimize the feedwater heaters of the power plants. The newly-built power plants work optimally at their design conditions; however, by aging, they often deviate from those conditions. Therefore, new optimal conditions are required to be determined for them. In this study, invoking a Predictive Model, the impact of different configurations of the feedwater heaters on the performance of the power plant is examined. It is shown that there are optimal values for the pressure of closed feedwater heaters. Following the optimization procedure of Conjugate Directions Method, the optimal pressures for bleeding off steam for all the closed feedwater heaters and the deaerator are achieved, simultaneously. The multi-variable optimization is carried out based on the maximal energy and exergy efficiencies as well as the maximal net delivered power of the cycle.