Parametric Simulation of Triple-Pressure Reheat Combined Cycle: A Case Study

Abstract

This paper presents a case study of the thermodynamic model on an existing actual combined-cycle gas turbine (CCGT) (MARAFIQ power plant) with a triple pressure reheat heat recovery steam generator (HRSG) and duct burner. An effort has been made to enhance the performance of the CCGT through a parametric study using a thermodynamic analysis. The effect of the ambient temperature and operation parameters, including compression ratio and turbine inlet temperature on the overall performance of CCGT are investigated. The code of the performance model for CCGT power plant was developed utilizing the THERMOFLEX software. The simulating results show that the total power output and overall efficiency of a CCGT decrease with the increase of the ambient temperature because of the increase the consumption power in the air compressor of a gas turbine. The totals power of a CCGT decreases with the increase of the compression rate while the overall efficiency of a CCGT increases with the increase of the compression ratio to 21, after that the overall efficiency will go down. The turbine inlet temperature also increases both total power and overall efficiency increase. It is concluded that the turbine inlet temperature has a strong effect on the overall performance of CCGT power plant. The simulation model gives a good result compared with MARAFIQ CCGT power plant.