Exergoeconomics of hydrogen production from biomass air-steam gasification with methane co-feeding

Biomass is one of the most promising energy sources for hydrogen production. However, biomass gasification has a low hydrogen content in the producer gas. To increase the hydrogen yield, the co-feeding of methane into biomass gasification is proposed in this study. The type of gasifying agent is a key factor in the determination of the content of the hydrogen product. To compare the designs and find the best performance criteria of a process, not only energy and exergy analyses but also a cost analysis of the process should be investigated. In the present study, the effects of various types of gasifying agent, i.e., air and both steam and air, for the biomass gasification with/without methane co-feeding are investigated through an exergoeconomic analysis. It is observed that the air-steam used as an agent achieves high energy and exergy efficiency. Methane co-feeding can improve the energy and exergy efficiency. In exergoeconomic analysis, the specific exergy cost (SPECO) method is applied to investigate the unit cost of hydrogen. The economic reveal that the biomass gasification using air-steam as an agent with methane co-feeding also presented the lowest unit hydrogen cost of 2.69 $/kg. The unit exergy cost of hydrogen is 0.068 $/kW h.