Container-Sized CO² to Methane: Design, Construction and Catalytic Tests Using Raw Biogas to Biomethane

Direct catalytic methanation of CO₂ (from CO₂/CH₄ biogas mixture) to produce biomethane was conducted in a pilot demonstration plant. In the demonstration project (MeGa-StoRE), a biogas desulfurization process and thermochemical methanation of biogas using hydrogen produced by water electrolysis were carried out at a fully operational biogas plant in Denmark. The main objective of this part of the project was to design and develop a reactor system for catalytic conversion of CO₂ in biogas to methane and feed biomethane directly to the existing natural gas grid. A process was developed in a portable container with a 10 Nm³/h of biogas conversion capacity. A test campaign was run at a biogas plant for more than 6 months, and long-time operation revealed a stable steady-state conversion of more than 90% CO₂ conversion to methane. A detailed catalytic study was performed to investigate the high activity and stability of the applied catalyst.