Development of Air Cooled Combustor for Mitsubishi G Class Gas Turbine

Mitsubishi Heavy Industries (MHI) pioneered the introduction of steam cooling technology for gas turbines with the introduction of the M501G in 1997. To date, 62 Mitsubishi G units have been sold making this series the largest steam cooled fleet in the market. The turbine inlet temperature (TIT) for this gas turbine is 1500 deg. C. The original M501G has been upgraded for air cooling applications. This upgraded version is called as M501GAC (G Air Cooled). Several Dry Low NOx (DLN) and cooling technologies from existing F and G series were applied to the upgraded M501GAC. The new GAC combustor was installed in the in-house verification Combined Cycle Power Plant, called T-Point, and verification tests of the combustor were conducted from November 2008. The air cooled M501GAC combustor demonstrated less than 15ppm NOx operation, stable combustor dynamics at all load levels, and high combustor ignition reliability making it suitable for daily start and stop operation at T-Point. Long term verification test is currently under way.