THERMODYNAMIC STUDY OF A 250 MWE COMBINED CYCLE POWER PLANT AT FULL LOAD AND PART LOAD CONDITIONS

Combined cycle power plants, especially the combination of gas turbine and steam turbine power plants as the topping and bottoming cycles respectively, have been used for power generation for a long period of time. The resultant efficiency is greater than that of the individual cycles. This paper deals with the design and energy and exergy analysis of a 250 MWe combined cycle power plant. Exergy destruction was found to be maximum in the combustor, followed by gas turbine and steam turbine, and stack. Hence any effort to improve/optimize the combined cycle power plant must focus on the combustor and the turbines as they involve high irreversibilities. The energy and exergy efficiencies have been found to be 40.7% and 39.1% respectively. Also, part load performance at 200 MWe and 150 MWe has been conducted.