Application of Catalytic Combustion Technology to Industrial Gas Turbines for Ultra-Low NOx Emissions

Abstract

An operating cycle had been developed for a catalytic combustion system applied to the Allison 501-KB7 engine. This cycle used overboard bleed of diffuser air to maintain a high fuel/air ratio at the catalyst and thus achieve a high combustor outlet temperature with attendant low CO and UHC emissions. For the design point of this engine, the emissions measured at full pressure and temperature in a subscale catalyst test rig were <1 ppm NOx and <2 ppm CO and UHC. Tests over the full operating cycle showed that the catalytic combustor system would achieve low emissions from 20 to 100% load. The use of catalytic combustion on a high efficiency gas turbine engine design was also evaluated. Pressures up to 20 atm and combustor outlet temperatures up to 1500°C (2730°F) were demonstrated with NOx emissions <2.2 ppm and CO and UHC <2 ppm. These results show that catalytic combustion is a viable technology for application to a high pressure, high temperature industrial gas turbine engine design.