Experimental studies of flame extinction in a swirl-stabilized oxy-fuel burner

Abstract

We report on an experimental investigation of oxy-fuel combustion carried out in a co-axial, horizontally-fired swirl-stabilized burner. Retrofitting possibilities and flame extinction have been investigated with methane or liquefied petroleum gas (LPG) as fuel and mixtures of oxygen (O2)–carbondioxide (CO2) or air as oxidant. Temperature profile measurements show that a higher oxygen concentration of around 33–34% by volume in the oxidizer is needed in oxy-fuel combustion to get temperature profiles similar to those for normal air combustion. Oxy-fuel flames have been found to be stable even for O2 concentrations less than 30% by volume, though at reduced peak flame temperatures. The results of extinction studies with CO2 or nitrogen (N2) dilution indicate that CO2-diluted flames are more prone to extinction by dilution than N2-diluted flames. The former get extinguished at an oxygen concentration of 21% by volume whereas the latter can be sustained at oxygen concentrations down to 15% by volume.