Laminar burning velocity with oxygen-enriched air of syngas produced from biomass gasification

Several studies on the laminar burning velocity of syngas mixtures have been conducted by various researchers. However, in most of these studies, dry air was used as the oxidizer, whereas very few studies have been conducted on syngas combustion in oxygen – enriched air. In this work, a numerical and experimental study on the laminar burning velocity of a mixture of H2, CO and N2 (20:20:60 vol%) was performed using air enriched with oxygen as the oxidizer, varying the oxygen content from 21% up to 35% for different equivalence ratios. Numerical calculations were conducted using three detailed reaction mechanisms and transport properties. Flames were generated using contoured slot-type nozzle burners, and Schlieren images were used to determine the laminar burning velocity with the angle method. The experiments were performed under the conditions of Medellin (1550 m.a.s.l.), 0.838 atm and 298 K. The laminar burning velocity increases with the concentration of the oxygen in the mixture due to the increase of the reaction rate; for a stoichiometric mixture, the laminar burning velocity increases by almost 25% with an increment of 4% of oxygen in the oxidant. However, the flammability limits also increase, allowing stable flames to exist in a wider range of equivalence ratios.