Membrane gas permeation in the upgrading of renewable hydrogen from biomass steam gasification gases

Combination of the biomass steam gasification and the membrane gas permeation is a potential process for the production of renewable hydrogen. This work first briefly reviews possible membrane materials for the hydrogen enrichment from biomass gasification producer gas mixtures. Subsequently, two permeator arrangements, a single stage and a two-stage with sweep, are evaluated through numerical modeling. The evaluation discusses the most essential upgrading parameters: achievable hydrogen purity, hydrogen recovery and energy requirement in the upgrading. It is shown that the two-stage arrangement using membranes with H2/CO2-selectivity of 9 allows production of hydrogen fuel with the hydrogen content of 98% in volume (v/v) and the hydrogen recovery of around 75%. Further improvement of the membrane H2/CO2-selectivity is necessary to enhance the process sustainability and economics.