Investigation on Flame Characteristics of Oxy-Fuel Combustion

Oxy-fuel combustion is currently being considered as a technology that could substantially reduce NO_x and CO₂ emissions. Currently the gas turbine industry has begun to consider implementing oxy-fuels on a large scale in some combustors. In an effort to better understand and characterize the fundamental flame characteristics of oxy-fuel combustion this article presents the results of stability and flame length experiments. From the results, the flame length primarily depends on the percentage of oxygen and fuel firing input. Flames with a fuel firing input of 1313 W had a higher flame length (275 mm) compared to the same fuel at a firing rate of 925 W (240 mm). It was observed that as the percentage of oxygen increased, the length of the flames decreased for both firing rates. The stability maps of CH₄-O₂ were plotted using six different tubular burner diameters, ranging from 1 to 6 mm. The flame from the 1 mm diameter burner tube tended to extinguish, even at lower mass flow rates due to a quenching effect. For larger burner diameters, 2 to 6 mm, the flames tended to flashback. It was also observed that the stability regime increased with an increase in CO₂ concentration in the fuel mixtures.