Impact of pre-decarbonization on biogas-to-hydrogen performance: A combined catalysis and simulation approach for economic analysis

Pre-decarbonization, as a conventional step in the steam reforming process for hydrogen production from biogas, lacks comparative studies on its impact on the steam reforming (SMR) and water-gas shift (WGS) processes, as well as on the overall process economics. In this study, the feasibility and economic advantages of omitting pre-decarbonization were investigated through catalyst performance evaluation and full-process simulation. Biogas conversion experiments were conducted using various SMR and WGS catalysts under feeds with pure CH 4 and different CO 2 /CH 4 ratios. The results reveal that the CO 2 content has a negligible effect on CH 4 conversion in the SMR stage (over 98% for all catalysts at 700 °C), and the final hydrogen yield decreases by only 3-5% as the CO 2 /CH 4 ratios increase. Two process routes (A: “Pre-decarbonization + SMR and WGS + H 2 purification”; B: “SMR and WGS + H 2 purification”), were established using Aspen Plus, and an economic assessment was performed for 500-1500 m 3 /h biogas feeding. The results indicate that the process without pre-decarbonization achieves a lower levelized cost of hydrogen (LCOH) across all capacities (2.00 USD/kg H 2 at 1500 m 3 /h). The cost difference is mainly attributed to the equipment cost of the pre-decarbonization unit (accounting for 33.7%-36.6% of total capital expenditure) and its high steam consumption. This study demonstrates that a biogas-to-hydrogen process without pre-decarbonization offers potential economic advantages, providing a research foundation for simplifying process design.