Abstract

In this paper, the simulation results of combined cycle power plants based on the use of supplementary fraction bypass heat from combustion chamber and gas turbine exit exhaust gases heat to use in HRSG, with reheat are presented. The analysis procedure is followed for finding both optimums Worknet and optimum efficiency. A fraction of hot gases heat from combustion chamber is bypassed to HRSG. Exit heat from gas turbine also passed through the HRSG. The simulation is carried out for different fuels and different air fuel ratios for different pressure ratios. The simulation codes are made in MATLAB. The significance of this kind of investigation give advantages of combine power plant that utilizes the waste energy for generation of steam to run the steam turbines. This leads to increase in power output in thermal efficiency. The performance of combined cycle depends upon the number of parameters like pressure ratios, types of fuel used, component efficiency, turbine exhaust temperature, degree of supplementary heating and condition of steam generation. It is noticed that fraction hot gases bypassed from combustion chamber to HRSG certainly give sufficient heat energy to generate steam at required pressure and temperature to obtain the optimum Worknet and optimum efficiency significantly.

Keywords

combined cycle power plants, supplementary heating, HRSG