Emission control of an ammonia-air flame in a coaxial tangential injection combustor at elevated pressure conditions

This study is the first to present the emission characteristics of the fuel staging method for a pure ammonia-air flame using a coaxial tangential injection combustor. The primary combustor used in this study had the same swirl number of 3.3 as in a previous study; however, the dimension of the combustor was increased to examine at a higher thermal load. The emissions of NO, NO2, N2O, and NH3 were measured simultaneously under an elevated pressure. Consequently, secondary ammonia injection (fuel staging) was confirmed to be effective for NOx abatement even under pressurized conditions. In addition, excessive secondary ammonia injection exhibited an additional NOx reduction effect coupled with the generation of unburned N2O and NH3. The optimized amounts of NOx, N2O, and NH3 were 83, 23, and 11 ppm (@15 % O2, dry), respectively. The results of this study are expected to be useful as significant design and operating data for pure ammonia gas turbines.