Hydrogen Production from Sorption Enhanced Biogas Steam Reforming Using Nickel-Based Catalysts

Hydrogen gas is a clean and sustainable fuel/energy carrier considered to be a possible alternative to fossil fuels. Sorption enhanced biogas steam reforming is a process which combines a CO2 adsorption unit with a hydrogen production unit. In the CO2 sorption section, CaO was selected as the adsorbent due to its high stoichiometric adsorption capacity. From the adsorption test, the highest adsorption capacity (0.2849 gCO2/gCaO) was achieved at a temperature of 873 K. Four types of bed arrangement were investigated using a feed gas with a CH4/CO2 ratio of 1.5, an S/C ratio of 3, a temperature of 873 K and at atmospheric pressure. The results indicate that the Type II system (Catalyst physical mixed with sorbent system packed in fixed bed quartz reactor, 0.8 g of 12.5 wt% Ni/Al2O3 mixed with 2 g of CaO) exhibits the highest improvement in CH4 conversion with the introduction of CO2 adsorption (93.0% and 81.7%, with and without CO2 sorption, respectively) and high purity hydrogen was produced (97.0% v/v and 62.3% v/v, with and without CO2 sorption respectively)