THERMODYNAMIC ANALYSIS OF COMBINED CYCLE GAS TURBINE FOR IMPROVING ITS THERMAL PERFORMANCE

Abstract

The objective of the presented work is to develop a Thermodynamic optimization method in order to optimize the efficiency of a combined cycle gas turbine (CCGT) power plant and suggest ways of improving the efficiency. The Thermodynamic analysis provides a complete diagnosis of the performance of the combined cycle power plant, both in energetic and in exergetic terms. The system considered in this thesis is a combined cycle power plant which couples the two power cycles, Brayton cycle (gas turbine), Rankine cycle (steam turbine). There are various ways in which the efficiency of both cycle individually can be improved. But when couple together optimization is different thing because improving efficiency of one cycle can adversely affect the efficiency of other cycle and of combined cycle gas turbine. By using thermodynamic analysis, parametric study is done in this work to find the optimum parameter at which efficiency of system is maximum. A program of numerical code is established using EES (Engineering Equation Solver) software to perform the calculations required for the thermodynamic analysis considering real variation ranges of the main operating parameters such as pressure, temperature, pressure ratio. The effects of theses parameters on the system performances are investigated. Parametric study has been performed using combined first and second law approach to investigate the effects of compressor air inlet temperature and pressure of steam on first and second law efficiency, power-to-heat ratio, exergy destruction in the system components.