Abstract
Although the higher Turbine Inlet Temperature (TIT) derives higher system efficiency in combined power generation system, it causes the higher NO_x concentration in open gas turbine system. So the closed gas turbine system with steam recirculation as working fluid has been noted because of its higher efficiency (η>60%) without any NO_X emission. However, it is needed to operate the closed gas turbine in lean burn condition to reduce CO emission caused by high temperature and high pressure. Excess O_2 feeding means the increasing of O_2 manufacturing power and gas compression power. So, we executed cycle simulations of closed cycle gas turbine system. The dependency of equivalence ratio on system efficiency was clarified.
