Shinji Akamatsu

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, 71 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). The latest 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. Also, oil firing capabilities was tested in May, 2010. Long term verification test is completed in fall 2010.Copyright

New Dry Low NOx Combustor for Mitsubishi M501/701G

MHI G class gas turbine was designed to operate with a Turbine Inlet Temperature (TIT) of 1500 °C. This elevated temperature results in high thermal efficiency but also can induce relatively high emissions. MHI has developed a new Dry Low NOx (DLN) combustor that improves this class turbine compliance with stringent environmental regulations imposed around world. In addition to targeting an environmentally friendly combustor with lower emissions, the redesigned DLN combustor also improves the stability margin. Verification tests of the new DLN combustor were conducted in a M501G1 gas turbine at MHI’s T-Point Combined Cycle Power Plant from May, 2005 to March, 2007. In addition to verifying lower emission levels, these tests confirmed a wide stable operation margin as well as the reliability and durability of the components. The new design is optimized to be retrofitted into existing G class engines. The combustor is now in mass production as a MHI’s standard combustor. This paper describes the design process applied for the new combustor, including the Computational fluid Dynamics’ (CFD) and other analytical tools used.Copyright