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

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.

KEYWORDS:

• MILD combustion
• oxy-fuel combustion
• O₂/CO₂ combustion
• propane
• diluent concentration

Acknowledgments

The authors gratefully acknowledge the support of National Natural Science Foundation of China (51976186).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [51976186].