Biomass gasification and catalytic methanation (biomethane)

Often referred to as the bio-synthetic natural gas (bioSNG) route, biomass is first gasified into syngas and the syngas is then converted into biomethane via methanation. Biomass with a high lignocellulosic content (e.g. wood, straw, residues from forestry and agriculture, municipal solid waste) is gasified via heating in an oxygen-restricted environment, producing a mixture of mostly hydrogen (H2), carbon monoxide (CO), carbon dioxide (CO2), and other hydrocarbons. This "syngas" is then cleaned, CO2 is removed and vented, and the remaining syngas is dried before undergoing catalytic methanation. Prior to methanation, a partial water-gas shift (WGS) reaction may be used to adjust the H2/CO ratio. Technical challenges revolve around tar buildup and removal during gasification.