The European Patent Office has granted Evonik Fibres GmbH, based in Schörfling (Austria), a patent for a three-stage process for membrane-based purification of biogas and natural gas

In the gas separation process, which has been developed by Evonik, binary gas mixtures such as raw biogas, which consists primarily of biomethane and carbon dioxide, can be separated very efficiently and cost effectively. In addition to increased yields and lower equipment and energy requirements – a second compressor is no longer required – the membrane process eliminates the need for additional purification, so that the enriched gas can be fed directly into the natural gas network.

Gas separation with SEPURAN® hollow-fiber membranes

At the core of the separation process are the innovative hollow‑fiber membranes of Evonik’s SEPURAN® Green brand. These consist of a high-performance plastic, developed by Evonik, which can withstand extreme pressure and temperatures. The membranes also have excellent selectivity. In combination with the three-stage separation process, recycling streams can be minimized which helps to optimize the energy costs of biogas processing plants.

With the purchase of the SEPURAN® Green membranes, Evonik’s contract partners – plant engineering companies – also receive a license to use this three-stage separation process. In turn, when a company buys a biogas processing plant with SEPURAN® Green membranes that has been constructed by Evonik’s contract partners, the plant can be operated using the patent-protected process.

In addition to the patents granted in the relevant markets in America and Asia, the three-stage membrane process developed by Evonik now enjoys legal protection in all the key European markets.

Evonik’s SEPURAN® product family includes membranes for biogas processing, nitrogen generation, and helium and hydrogen processing. In 2011, SEPURAN® Green membranes for biogas processing were introduced successfully to the market and since then, have been deployed successfully in more than 100 biogas plants worldwide.


Volker Wehber

Director SEPURAN® Green

Phone +49 6151 18 4513