Advanced Dry Low NOx Combustor for Mitsubishi G Class Gas Turbines

Abstract

Design features and verification results for Mitsubishi Heavy Industries’ (MHI) latest gas Dry Low NOx (DLN) combustor technology for 1500°C G-class gas turbines is presented. Key design improvements include: A) Inlet aerodynamics: CFD based design air inlet for improved flow uniformity into the pre-mixers. B) Fuel/air mixing: integrated fuel injector and swirler to decrease local flame hot-spots and reduce NOx while preventing flashback. C) Combustor aerodynamics: redesigned flame holding baffle and combustor outer wall to achieve better flame stability and NOx reduction. D) Acoustic resonator: two acoustic resonators, one in the liner to prevent high frequency combustion dynamics and the other in the bypass valve for low frequency dynamics. Tests were conducted to verify the new DLN combustor by installing it in a M501G1 gas turbine at MHI’s T-Point combined cycle power plant, with more than 1500 special measurements. Following the preliminary verification period the combustor was installed at the same plant for long-term operation. The results demonstrate the following capabilities: A) Less than 15ppm NOx operation with turn down to 60% load. B) Stable combustion dynamics at all load levels. C) High combustor ignition reliability. D) Suitable for daily start and stop (DSS) operation. E) Good reliability and durability. F) Retrofitable to existing 501G and 701G gas turbines.