Effect of H2 and CO in syngas on oxy-MILD combustion

This paper investigates the effect of adding H2 and CO to a syngas on oxy-MILD combustion. This work employs a Perfectly Stirred Reactor (PSR) model to calculate the autoignition temperature and the critical oxygen concentration for different component fuels under oxy-MILD conditions. Our investigation obtains the critical O2 concentration for oxy-MILD combustion of various H2/CO/CH4 component fuels. The results indicate that adding H2 to CH4 significantly reduces the minimum O2 concentration required for achieving the MILD state while adding CO has little effect. Furthermore, using the novel PCA method, we analyze characteristic chemical time scales for oxy-MILD combustion for different fuel ratios. We conclude that the mixture containing H2 and CO can be used as fuel for oxy-MILD combustion, as its characteristic chemical time scale is comparable to the turbulent time scale, resulting in Da number close to unity. However, achieving a steady MILD combustion state is more challenging than methane due to reduced ignition delay times. Moreover, syngas with various ratios of H2/CO presents the potential for controlling the MILD combustion process.