Knowledge Base

The process of upgrading biogas starts with cleaning the raw biogas of trace impurities, followed by separating the methane from the CO₂ to concentrate on natural gas quality. H₂S is largely removed within the digester tank itself through a biological process using netting under the membrane roof, with HoSt Carbon Clean® activated carbon filters providing a polishing step to remove any residual H₂S before the gas reaches the upgrading unit. The cleaned biogas then passes through HoSt’s membrane-based upgrading system, which separates CO₂ molecules from methane molecules across a selective membrane, concentrating the methane into biomethane while venting or capturing the separated CO₂. At HoSt’s Charlton Park plant in the UK, for example, this process upgrades biogas with a methane concentration of 56% to a product gas of 97% methane at an efficiency of 99.5%, after which the biomethane is distributed through the existing gas grid.