Due to governmental incentives and growing environmental awareness, it becomes increasingly attractive to upgrade biogas to natural gas quality and inject it into the natural gas grid or to use it as transport fuel. In this way, the biomethane can be utilized with the highest energy efficiency. Progressively, effort is being put into the utilization of organic waste streams in anaerobic digesters, producing useful products such as fertilizers and biogas. DMT has been developing biogas treatment plants for over 25 years, closely following market developments.
To upgrade raw biogas to biomethane, it is required to remove unwanted and harmful gases, such as carbon dioxide (CO2) and Hydrogen Sulphide (H2S). Several biogas upgrading technologies are available for the upgrading of biogas. The choice and configuration for a biogas upgrading plant is a tailor-made fit between customer requirements, (local) energy demand and operational aspects. However, for most situations, especially for plants up to 1000 Nm3/h, the Carborex MS system (based on an ingenious, multi-stage, high selective membrane system) offers the best economics as well as several unique technical advantages. The DMT Carborex MS is a compact modular and containerized unit, which applies high selective gas membranes for biogas upgrading. The upgraded gas has a methane concentration up to 98-99% CH4, which greatly reduces the consumption and cost of propanisation. This system has the highest energy recovery available (96-98%), therefore, it maximises revenues. The CO2 is recovered as >99,5% pure.
Recent market data shows that the number of biogas upgrading installations based on membrane technology is growing quickly. In this article, DMT will showcase last year’s operation data of the Carborex MS plant at Poundbury, which is currently the largest commercial biogas upgrading plant in the UK. Furthermore, the prospects for membrane based biogas upgrading, especially with regards to the shift towards larger scale application, will be described.
Keywords: Carborex MS, Biogas, Bio-methane, Gas separation, Green gas, highly selective gas membrane, Membrane separation, Upgrading.