Compact Membrane Systems reports successful biogas pilot demonstration

Compact Membrane Systems (CMS), a firm specialising in separation technology, has completed the first pilot demonstration of Optiperm™ biogas.

The latest addition to the CMS portfolio is aimed at enabling the clean energy transition underway in the biogas sector, a market valued at $55 billion (€45 billion), according to CMS.

Optiperm biogas holds the potential to create pipeline ready gas with a ‘simpler and less expensive product’. Such a technology solution would enable local farms, landfills, and other sites to process and use their own biogas product, or sell it.

Optiperm biogas targets the separation of methane from CO₂ with fewer stages and less compression than existing membrane solutions, addressing the biogas market. CMS completed its first pilot demonstration and has proven membrane stability, and achieved 90% methane purity with a single-stage membrane unit.

The process reduces the stages, compression, and pre-treatment needed to upgrade biogas streams. The lower operating pressure (2-3 bara) makes the upgrading process more energy efficient than current high-pressure membrane solutions.

The fluoropolymer nature of the membranes provides stability in hydrogen sulphide (H₂S) and resistance to ‘common poisons’ like hydrogen, water vapour, and CO. The technology is scalable and can produce economically viable biogas upgrades for small, medium, and large streams. Optiperm biogas permeates the CO₂, water, and H₂S, leaving upgraded methane in the retentate.

Working with Dickinson College Energy projects manager Matt Steiman, a spiral wound module system was installed at the Dickinson College Farm in late 2020. During the pilot installation, Optiperm biogas demonstrated stability and verified the performance that was measured in CMS laboratory testing. The unit took feed directly from the digester with no pretreatment and operated at a feed pressure of 2.7 bara. The feed contained 56-60% methane with balance CO₂, 300 parts per million (ppm) H₂S and was saturated with water vapour.

In a single stage, the process achieved: stable performance for two months, 90% methane product, 90% methane recovery, 80% CO₂ in permeate stream, 8x H₂S reduction (from 300 ppm to 37 ppm).