바이오가스의 수증기 복합 개질 반응의 열역학적 평형 계산 및 최적 반응 조건 연구

This study explores the optimal reaction condition for combined steam reforming of biogas produced from organic waste by conducting thermodynamic equilibrium analysis (Gibbs free energy minimization). The ratio of methane to carbon dioxide conventionally produced in biogas plants is fixed at 60 : 40. CH4 conversion, CO2 conversion, H2 yield, CO yield, carbon yield, and H2/CO ratio are estimated at various H2O/(CO2 + CH4) ratios (0 ~ 3.0) and temperatures (500 ~ 1000℃). The optimal reaction condition was explored with consideration of the amount of generated steam, the conversion, the yield, and the carbon yield . When the H2O/(CO2 + CH4) ratio is above 1.5, carbon formation can be avoided for all temperature ranges. However, the H2 yield at the same ratio is lower than that at thermodynamic equilibrium. This is due to the reverse water-gas shift reaction. By contrast, when the H2O/(CO2 + CH4) ratio is 2.0, the conversion and yield in the experimental results are consistent with those at thermodynamic equilibrium. Thus, it can be confirmed that the optimal reaction for hydrogen production from the combined steam reforming of biogas occurs at an H2O/(CO2 + CH4) ratio of 2.0 and a temperature of at least 650℃.