Exergy and energy analysis of fuel regime changes in a combined cycle power plant

In this study, a dual pressure combined cycle power plant without duct burner for three types of fuel has been investigated. The main objective of this paper is to specify the effect of changing the fuel poperties on cycle performance and finally introducing the best choice. Applying the results, one can see that the highest exergy loss occurs in the combustion chamber and maximum energy and exergy efficiency are obtained via natural gas. Also the results show that in HRSG, the most exergy loss for the three types of fuel occurs at high pressure evaporator. Furthermore the first and second law efficiency for natural gas is 2.34% and 4.69% more than oil fuel. Finally, by comparing the performance parameters of plant, it is concluded that the natural gas is the best fuel and gasoline can be considered as the alternative fuel.