Stability and performance characteristics of a laboratory-scale MILD combustor fed with syngas. Effect of H2/CO ratio

Abstract

This work presents the stability and performance characteristics of a laboratory-scale combustor fed with syngas and operating in the Moderate or Intense Low oxygen Dilution (MILD) combustion regime. The device was operated at 12-kWth using syngas with different H2/CO composition (H2/CO by v/v = 1-3). The influence of the fuel composition on the combustion stability, thermal efficiency, pollutant emissions, and distribution of heat flux within the combustor are presented for a range of values of the heat extraction. It was found that MILD combustion can be successfully stabilised within the device over a broad range of operating conditions and fuel type, with low CO and NOx emissions. The addition of H2 to the MILD process was found to increase its stability limits and NOx emissions. Regardless of the fuel type, similar thermal performance was found for all cases investigated. This provides evidence that the device can i) efficiently operate with low-calorific fuels and ii) accommodate for variability in the composition of the syngas fuel stream.