Experimental and Numerical Investigation of Laminar Burning Velocities of Artificial Biogas Under Various Pressure and CO₂ Concentration

¹ Institute of Fluid Science, Tohoku University, Sendai, Miyagi 980-8577, Japan
² Mechanical Engineering Department, Petra Christian University, Jl. Siwalankerto No.121-131 Surabaya 60236, Indonesia
³ Centre for Sustainable Energy Studies, Petra Christian University, Jl. Siwalankerto No.121-131, Surabaya 60236, Indonesia

^* Corresponding author: willy@petra.ac.id

Abstract

As a renewable and sustainable fuel made from digestion facility, biogas is composed predominantly of methane (CH₄) and carbon dioxide (CO₂). CO₂ in biogas strongly affects its combustion characteristics. In order to develop efficient combustors for biogas, fundamental flame characteristics of biogas require extensive investigation. In understanding the influence of CO₂ concentration and mixture pressure on biogas combustion, the effects of CO₂ concentration on the laminar burning velocity of methane/air mixtures were studied at different pressures. The studies were conducted using both numerical and experimental methods. The experiment was conducted using a constant volume high pressure combustion chamber. The propagating flames were recorded with a high speed digital camera by employing Schlieren photography technique. The numerical simulation was carried by utilizing CHEMKIN-PRO with GRI-Mech 3.0 employed as the chemical kinetics model. The results show that the laminar burning velocity of methane-air mixtures decreased with an increase in CO₂ concentration and mixture pressure. Therefore, the burning velocity of biogas mixtures may decrease as the amount of CO₂ in the gas increases.