The biogas is extracted from the digesters, purified and processed via methanation into high-purity methane (CH₄), which is suitable for use as a fuel in accordance with DIN EN 16723-2. First, pollutants such as hydrogen sulphide (H₂S) are removed from the biogas at ambient temperature. The gas is then compressed, heated and filtered. Hydrogen (H₂) is subsequently added, which reacts with the carbon dioxide (CO₂) from the biogas in the temperature-controlled tubular reactor. This produces methane and the by-product water, which is separated in a condensate trap. The result: a gas with a significantly higher methane content (> 95%) and minimal CO₂ content – ideal as a fuel or for chemical processes.

The tubular reactor contains a fixed bed of catalyst and can be controlled across three temperature zones. An automatic air-cooling system prevents overheating. In addition to operating with biogas from the digesters, the plant can also be run using pure gases such as methane, CO₂ or hydrogen. This enables precise testing of new catalysts, rapid measurements of different gas compositions and long-term trials under controlled conditions.

The pilot plant is highly automated, flexible in use and offers the possibility of coupling methanation with other processes – ideal for research and development of new methods for utilising biogas.