Mid Sweden University

The use of cheap product gas from biomass air gasification to produce methane via anaerobic digestion is a novel and potential pathway for the large-scale production of biomass-based substitute natural gas (BioSNG). In this experimental work, the product gas biomethanation (PGB) was studied with respect to the biosludge enrichment and inoculum partial grinding as well as the mesophilic and thermophilic conditions. The results show that the biosludge enrichment can effectively stop methanogenesis inhibition from the product gas, particularly CO, thus increase the biomethanation reaction rate and shorten the reaction start-up time. The inoculum partial grinding treatment can clearly change the microorganism composition and effectively reduce the diversity of microorganisms in the mixed bacterium system for the mesophilic biomethanation, thereby improving the product gas biomethanation efficiency, which is limited for the thermophilic biomethanation.