Experimental and numerical study on hydrogen enriched biogas explosion in tee-junction pipe

Abstract

Biogas is considered as a valuable source of renewable energy. Indeed, it can be turned into useful energy (heat, electricity, fuel) and can contribute to reduce greenhouse gas emissions. Knowledge of its combustion characteristics is a very important practical issue. The aim of this study is to experimentally investigate the biogas explosion characteristics in a 0.044 m3 T-junction pipe. The fuel used was varied in concentration between 5 to 15v/v %. The effect of hydrogen enrichment was also analyzed. Hydrogen fuel with 5%, 10% and 15%, will be added, to the fuel-air mixtures, at stoichiometric concentration (f=1.0). From the experimental findings, it was found that the biogas-air mixtures gave 2 times lower the maximum overpressure as compared that of hydrogen enriched biogas-air mixtures. The maximum overpressure occurred on enriched hydrogen of 5,10, 15%v/v was 2.29 barg, 2.21 barg and 2.27 barg, respectively. Numerical analysis done by FLACS simulation illustrated that the data obtained was about 30 - 70% under prediction from the experimental data. However, the simulation result gave a good agreement on flame propagation and pressure profile as recorded during experimental work; the pressure attained the highest at the end pipe and the highest flame speed recorded was at the tee-junction region.