The removal of CO₂ from biogas using a laboratory PSA unit: design using breakthrough curves

The production of biomethane from biogas offers the possibility to obtain chemical resources fuels from combustion engines, gas turbine and fuel cells. However, each biomethane application requires specific treatment. This work is focused on the removal of CO₂ from biogas as a fundamental step in biogas treatment. A laboratory scale PSA unit is introduced in this paper. The extruded activated carbon was used to construct the fixed bed adsorption layer. The maximum sorption capacity of CO₂ was determined from the adsorption isotherm of pure CO₂ carried out in a high pressure thermogravimeter. Breakthrough curves of CO₂ and CH₄ were determined for different volumetric flows of feed. The results were applied for the optimisation of PSA time in order to maximalize the suppression of CO₂ from upgrading CH₄. The concentration of CH₄ is more than 98 % after the upgrading process. The total efficiency of the process was 77 %.