(35a) Separation of Binary Mixtures Containing CO2: From Adsorption Equilibrium to Fixed Bed Dynamics

The increasing emissions of carbon dioxide have been claimed to lead to global warming, as a consequence of the intensification of the greenhouse effect in our planet. Therefore, technologies under the concept of Carbon Capture and Storage (CCS) have been developed with the purpose of reducing, or at least stabilizing, the concentration of CO₂ in the atmosphere. Adsorption-based methods are a promising cost-efficient technology, particularly in continuous mode, such as Pressure Swing Adsorption (PSA). The knowledge of adsorption fundamental equilibrium relationships, together with a comprehensive understanding of fixed bed dynamics are essential tools for the design of industrial units like PSA. The objective of the present work is to evaluate the suitability of commercially available activated carbon (AC) and MOF samples for CO₂ capture from CO2/N2 (typical of flue gas scenarios) and CO2/CH4 (typical of biogas and natural gas upgrading) mixtures. Single component adsorption data and binary breakthrough curves were obtained experimentally and modelled by pertinent thermodynamic and transport phenomena equations. The CO2/CH4 and CO2/N2  selectivity of the samples  was also analyzed and compared under static and dynamic conditions. Finally, different PSA configurations were examined and compared for the two binary separations under study.