FINDING THE OPTIMAL ADSORBENT FOR CO2 SEPARATIONS BY PSA

摘要

The problem of anthropogenic CO2 emissions has revived interest in the development of improved adsorbents for the elimination of CO2 from gas mixtures (synthesis gas, flue gas, biogas) by Pressure Swing Adsorption (PSA). Adsorbent selection is usually based on two criteria: (1) The working capacity Δn is defined as the difference between the adsorbed amount of CO2 under adsorption and desorption conditions. It corresponds to the amount that can be adsorbed during each PSA cycle. The higher the working capacity, the smaller the size of the column. (2) The purity of CO2 that can be achieved depends on the co-adsorption of other components in the gas mixture. The selectivity is defined as the ratio of the adsorbed amounts of CO2 and of the competing component divided by the ratio of their molar fractions in the gas phase.