Comparison of biorefinery characteristics: Photo-fermentation biohydrogen, dark fermentation biohydrogen, biomethane, and bioethanol production

Biorefinery technology promotes the realization of the Paris Agreement, China's achievement of its carbon peak, and carbon neutralization. Photo-fermentation biohydrogen production, dark fermentation biohydrogen pro-duction, biomethane production, and bioethanol production are several promising biorefinery methods. In this study, corn stover was used as the raw material, and the gas, liquid, and kinetic characteristics of four biorefinery methods were investigated. The production yield, gross thermal energy, economy, and greenhouse gas emissions of the target product per gram of corn stover were studied. The maximum yields of photo-fermentation bio-hydrogen production, dark fermentation biohydrogen production, biomethane production, and bioethanol production were 68.4 mL/g dry matter (DM), 47.4 mL/g DM, 196.0 mL/g DM, and 2.7 g/L, respectively. The maximum gross thermal energy obtained from biomethane production was 7017.3 J/g DM. The maximum economy of 1.4 RMB/g DM was observed in photo-fermentation biohydrogen production. The highest green-house gas emission of the target product from biomethane production was 196.0 mL/g DM. The results provide a reference for the efficient utilization of biomass resources and a comprehensive evaluation of biorefinery technology.