Parametric Analysis of Triple Pressure HRSG in Combined Cycle Power Plant

Abstract

Combined cycle power plants play an important role in the present energy sector. Combined Cycle plants couple a Brayton cycle with a Rankine cycle. For the combined power plants, the optimization of the heat recovery steam generator (HRSG) is of particular interest in order to improve the efficiency of the heat recovery from gas turbine exhaust to maximize the power production in the steam cycle. In the present study effect of different operating variables such as exhaust gas flow rate, exhaust gas temperature, pinch point, approach point, steam temperature, steam pressure on the performance of HRSG has been investigated. Triple pressure steam cycle is considered for the bottoming cycle to reduce irreversibilities during heat transfer from gas to water/steam. The cycle is analysed by using energy and exergy analysis. It is observed that in triple pressure cycle selection of IP and LP pressures, and LP pinch are identified as dominant parameters having impact on heat recovery steam generator performance.