Molecular Simulation of Adsorption Separation of CO₂ from Combustion Exhaust Mixture of Commercial Zeolites

The adsorption thermodynamics and kinetics of CO2 and six combustion products (H2O, SO2, N-2, O-2, NO and NO2) of two most commonly used commercial zeolites (13X and 5A) were studied based on validated molecular simulations. Adsorption isotherms at wide range of temperatures (253-333 K) were fitted by a Langmuir model, obtaining equilibrium parameters including the adsorption capacity, strength, heterogeneity and CO2 selectivity from the mixture. The diffusion coefficients, isosteric adsorption heats and distributions of potential energy were simulated for further explanation. The comprehensive evaluation results suggest that, in actual combustion product mixtures, the presence of H2O in combustion products has a significant impact on CO2 capture efficiency. Under the influence of water, the adsorption capacity of CO2 was reduced by over 80%.