Model development for biogas generation, purification and hydrogen production via steam methane reforming

Abstract

Biogas, a renewable energy source produced by the anaerobic digestion of organic matter, can reduce greenhouse gas emissions. The purification and hydrogen conversion of biogas enhance its versatility as an energy carrier and reduce dependency on fossil fuels. This sustainable process fosters a cleaner future. In this study, simulation models were used to optimize the process conditions and assess the technical feasibility of the biogas-to-hydrogen production. In addition to the anaerobic digestion process, simulation models were also developed for biogas purification via water scrubbing and hydrogen production via steam methane reforming (SMR) using Aspen Plus simulation software. Simulation results demonstrated that the maximum methane yield of 520 mL/gVS was achieved at an organic loading rate of 20 g/L, while the minimum yield of 230 mL/gVS was observed below 10 g/L. Optimal anaerobic digestion temperature for maximum gas yield (548 mL/gVS) was found to be 30 °C, with a decrease in biogas production above 40 °C. In the water scrubbing model, maximum CO2 absorption occurred at 15 bar pressure, whereas reducing the pressure to 5 bar significantly lowered the absorption rate. The SMR model yielded the highest hydrogen production rate of 10.15 kg/h using purified methane (99%) as feed, but the methane content was affected by the biogas composition.