Evonik entered the biogas upgrading market in 2011 and has since become the global leader in membrane-based upgrading, with more than 1,300 plants in over 30 countries now running on the technology.
SEPURAN® Green modules consist of hollow fibre membranes made from Evonik's own high-performance polymers, housed in stainless steel. The membranes separate carbon dioxide from methane at ambient temperature with no water, solvents or other consumables, and they are highly resistant to hydrogen sulphide, VOCs and variations in feed gas composition and flow. Modules are available in 4", 6" and 11" diameters and can be connected in series, so a system can be sized and later expanded to suit the plant.
The membranes are applied within Evonik's patented three-stage separation process, which removes the need for a second compression step and lifts methane recovery above 99.5%, keeping both capital and operating costs down. The process can be configured for low-pressure operation, very low methane slip, or LNG-ready biomethane with CO₂ down to 50 ppm. The result is grid-quality biomethane that directly substitutes for natural gas, along with a stream of biogenic CO₂ that can be recovered as a second product.