Biogas upgrading represents one of the most interesting options for producing methane from alternative sources to fossil fuels. The current commercially available upgrading processes entail firstly the separation from the biogas of CO₂ which is released to the atmosphere. Within the scope of the "UPGAS-LOW CO2" project, our group has developed a CO₂ capture and storage process which can allow to achieve potential advantages in terms of greenhouse effect mitigation. The process consists in the absorption of the CO₂ contained in the biogas using a potassium hydroxide solution followed by the treatment of the effluent by carbonation with industrial residues that allows at the same time to regenerate the initial alkaline solution and to store CO₂ in a solid phase (calcite). The process has been developed and optimized at lab-scale, allowing to design and build a pilot plant that has been installed in a landfill site (Casa Rota, Arezzo). The experiments performed both in the laboratory and in the pilot scale plant have allowed to verify the feasibility of the proposed process. The evaluation of the technical and economical sustainability of the process as a mitigation option for greenhouse gas emissions is currently under way.

Collaborations

Partners of the Upgas-LowCO2 project, among which the University of Florence, BOKU University (Austria) and Universitat Autònoma de Barcelona (Spain).