Recently, high efficiency and operational flexibility are required for thermal power plants to reduce CO2 emissions and to introduce renewable energy sources. We study the advanced humid air turbine (AHAT) system, which appears to be high suitable for practical use because its configuration is simpler than that of gas turbine combined cycle power plants (GTCCs). Moreover, the thermal efficiency of AHAT system for small and medium-size gas turbines is higher than that of GTCCs.
To verify feasibility of this system and the cycle performance of AHAT system, a 3MW-class pilot plant was built in 2006 by Hitachi, Ltd., which mainly consists of a gas turbine, a water atomization cooling (WAC) system, a recuperator, a humidification tower and a water recovery tower. Through the operational test from 2006 to 2010, we confirmed the feasibility of the AHAT as a power-generation system, and various characteristics such as the effect of changes in ambient temperature, part-load characteristics, and start-up characteristics.
Next step, a 40MW-class pilot plant was built in 2011 and started operational tests. This system mainly consists of a dual-shaft heavy duty gas turbine, a WAC system, a recuperator and a humidifier. As a result of the operational test, it has been confirmed that the pilot plant output achieved rated power output. In this paper, we show the 40MW-class pilot plant running test results, and evaluate thermal characteristics of this plant and the effect of WAC and humidification on performance of this gas turbine system.