Energy analysis of Brayton combined cycles

Economic and environmental considerations dictate the need for improved fuel utilisation in thermal power stations. To meet this goal, a design project was undertaken to assess the suitability for combined cycle application of different gas turbine (GT) cycles: simple, intercooled, reheated, intercooled/reheated, intercooled/reheated/regenerative cycle. Comparative figures for efficiency and performance were obtained. Exergy analysis will lead to an optimum plant. The proposed combined cycle plant would produce 300 MW of power (200 MW GT cycle and 100 MW steam cycle). The reheated GT is the most desirable exergetically, mainly due to its high exhaust gas temperature which results in high steam cycle thermal efficiency.