Effect of air/fuel nozzle arrangement on the MILD combustion of syngas

Abstract

The effect of air/fuel nozzle arrangement on MILD (Moderate or Intense Low-oxygen Dilution) combustion of coal-derived syngas under lean operating condition was evaluated in a parallel jet combustor. The results were presented on flow field using non-reactive numerical calculation and on OH* chemiluminescence images and exhaust emissions using experiments. The increase in equivalence ratio aids in the reduction of peak flame temperature and in the distribution of reaction volume. The critical equivalence ratios above which MILD combustion occurred were identified for four MILD configurations. The MILD configuration with both air and fuel injected from the opposite side of the combustor exit was observed to achieve MILD combustion at leaner condition than other three configurations. The MILD scheme was established for syngas fuel under highly lean condition with low NOx and CO emissions.