Experimental Investigation of Flame Characteristics of H2-Enriched Biogas Under Different Swirl Numbers

Biogas, derived from human waste or industrial byproducts, is considered one of the most environmentally acceptable fuels. However, such fuels often exhibit relatively low efficiency, making it essential to develop technologies that facilitate their effective combustion. This article investigates the combustion of biogas with the addition of hydrogen at varying degrees of flow swirling. For this purpose, a burner was used in which methane, hydrogen and CO2 were mixed in a mixer. The studies revealed that increasing the proportion of hydrogen in biogas leads to an average 15% rise in the NOx concentration. Additionally, an increase in the degree of swirling has a positive effect on NOx generation. On the other hand, a higher proportion of hydrogen reduces the concentration of CO in the exhaust gases. The presence of ballast gases, such as CO2, generally results in relatively low NOx levels when combined with a high swirling number. The analysis of combustion products for CO2 indicates a 14% increase in CO2 proportion. The highest concentrations of CO2 were observed in biogas with the highest CO2 ballast content. In terms of reducing NOx and CO, SW = 1.3 is the most successful. On the other hand, this angle leads to an increase in the CO2 concentration.