Effect of Carbon Dioxide on Flame Characteristics in Biogas External Premix Combustion

Biogas is a renewable and environmentally friendly alternative fuels. Biogas is produced from the fermentation process which consists of mostly CH4 (50-75%) and CO2 (up to 50%) and a smaller amount of H2, N2, O2, and H2S, in which it varies from source. There are several related studies about the characteristics of biogas combustion and external combustion. This research focus on effects of CO2 as the most abundant inhibitors in biogas towards its effects on external combustion process. This research was conducted by burning a stoichiometric mixture of fuel (CH4 and CO2% range 0-50%) and oxygen in the external test equipment premixed methane combustion with a 5 mm nozzle diameter. The results showed that the level of CO2 affects the formation of flame angle and flame height. The increase in CO2 content within the fuel mixture will decrease the flame height and moreover, more CO2 content also creates larger flame angle.