Separation of CO2 and N2 on a hydrophobic metal organic framework CALF-20

•CALF-20 is a hydrophobic MOF commercialized for industrial CO2 capture.•Detailed unary and binary equilibrium data on CO2 and N2.•Breakthrough experiments show excellent separation of CO2/N2; model predicts trends.•VSA based CO2 capture using CALF-20 studied through process optimization.•CALF-20 meets 95%purity, 90%recovery targets; outperforms Zeolite-13X & Mg-MOF-74. Adsorption equilibrium of pure CO2 and N2 on calgary framework-20 (CALF-20), a hydrophobic metal-organic framework (MOF), at various temperatures was measured using volumetric and gravimetric methods. The dual-site Langmuir isotherm was used to describe the pure CO2 and N2 equilibria. The competitive CO2/N2 adsorption and the column dynamics were measured using the dynamic column breakthrough technique. Various compositions of CO2/N2 were examined to obtain the competitive CO2/N2 isotherm. A one-dimensional column model was used to simulate the dynamic column breakthrough experiments. Both composition and temperature histories showed a good agreement between the experiments and simulations. A four-step vacuum swing adsorption (VSA) with a light product pressurization configuration was used to evaluate the ability of CALF-20 to capture CO2 from the flue gas containing 15 mol% CO2 and 85 mol% N2 under dry conditions. The results show that a 95% CO2 purity and 90% recovery could be obtained using CALF-20, and its performance was comparable with the benchmark materials zeolite 13X, UTSA-16, under these VSA conditions.