Effect of oxygen enriched air on porous radiant burner performance and NO emissions

Gas fired radiant burners are used owing to their simplicity, low cost and to avoid the difficulties and disadvantages of conventional burners i.e., low dynamic range and high production of pollutants. On the basis of this combustion principle, combustion characteristics of porous medium gas burners have been experimentally studied to investigate parameters affect the performance of porous medium burners, and the effect of oxygen enriched air on the performance. The combustion in porous inert media was investigated using mullite as a burner and liquefied petroleum gas “LPG” as a premixed fuel with air to show the effect of equivalence ratio and firing rate on the radiation efficiency, surface and exhaust gas temperatures. Radiation efficiency up to 45% can be achieved depending on operating conditions. The surface temperature was much lower than the adiabatic flame temperature of the LPG-air mixture at the same equivalence ratio. The improvement of the burner performance, using oxygen enriched air is investigated. The oxygen in the combustion air was increased up to 25%. The experimental results showed that the radiation efficiency of the burner was increased markedly with rising oxygen concentrations in the combustion air. The surface temperature also increased, while the exhaust gas temperature decreased.

► A porous radiant burner was examined for a premixed flame.
► Burner performance was studied for different firing rates and equivalence ratios.
► Radiant burner exhibits a reasonable efficiency and low surface temperatures.
► Radiation efficiency increased noticeably with rising oxygen in the combustion air.
► Oxygen enriched air slightly increases surface temperature and has no effect on NO.