Molecular simulation, experiments and modelling of single adsorption capacity of 4A molecular sieve for CO2–CH4 separation

Abstract

ABSTRACTMonte Carlo simulation of CO2 and CH4 adsorption on zeolite 4A is carried out in grand canonical Monte Carlo (GCMC) simulation. LTA framework was used to reproduce the structure of zeolite 4A. A comparison between the structure and properties of this zeolite and 13X, ZSM-5, 4A and 3A is performed and the results are included in the article. Universal force field was used for calculation of intermolecular forces. Our own experiments were also carried out to reinvestigate the simulation results. Ewald summation method was used for calculating electrostatic forces and atom based method was applied for van der Waals forces. The simulation results show good agreement with experimental results. Highest CO2 adsorption capacity of zeolite 4A was in good agreement with experiments at the same pressure ranges, and was found to be 3.17 mol/kg from GCMC. Isosteric heat of adsorption was calculated to find the heat released during adsorption of each gas. Finally simulation results were fitted to four isotherms to find the best fit.