Medium-Btu Fueled Gas Turbine Combustor for Use in LGCC (1st Report, Low NOx Combustion Method Using Nitrogen Injection

Abstract

The flame temperature of oxygen-blown medium-Btu gasified coal fuel is higher and so NOx production from nitrogen fixation is expected to increase significantly. We have started to develop low NOx and stable combustion technology using medium-Btu gasified coal fuel. In this paper, based on the fundamental combustion tests using the small diffusion burner, we have through out the new combustion technique which injects nitrogen directly into the high temperature region in the combustor for low NOx and stable combustion. A gas turbine combustor with a swirling nitrogen injection function designed with new combustion technique was constructed and the performance of this combustor was evaluated under atmospheric pressure conditions and operational conditions. From the test results, it is confirmed that : (1) This new combustion technique with nitrogen direct injection results in a significant reduction in NOx production from nitrogen fixation, 8 ppm or less (corrected at 16% O2) in the gas turbine operational conditions for IGCC ; and (2) CO emission concentration decreased to a significant level, as low as 10 ppm, under operational conditions, or combustion efficiency was almost always 100%. From the above results, this combustor has an excellent performance under the operational conditions in IGCC, and bright prospects of low NOx and stable combustion technology of the medium calorific fuel are obtained.