Numerical study on combustion performance of propane non-premixed mild in O2/CO2 atmosphere

Abstract

ABSTRACT Moderate or intense low-oxygen dilution (MILD) combustion is one of novel clean combustion technologies. Propane MILD combustion in CO2/O2 atmosphere is investigated in a 20 KW MILD combustion furnace by numerical simulation. The results indicate propane MILD combustion is established and stable in O2/CO2 atmosphere instead of N2/O2 atmosphere, and O2/CO2 atmosphere leads to lower average temperature in the furnace, better temperature uniformity, as well as higher CO emission. The dilution concentration of CO2 affects the thermal and chemical performance in the propane MILD combustion, such as temperature distribution, propane pyrolysis, exothermic rate, free radical OH and CO distributions in the furnace. CO emission always keeps several thousand ppm in all CO2 cases, which indicates that CO emission and burnout are the key problem in propane MILD combustion in O2/CO2 atmosphere. It is concluded by analyzing these factors that in the range of 73%~85% of CO2 dilution concentration, the 79% Case presents best, which is closely related to the multiple effects of CO2 physical dilution, jet entrainment, jet penetration, and chemical reaction.