Molecular dynamic simulation of carbon dioxide, methane, and nitrogen adsorption on Faujasite zeolite

Abstract

Removing impurities such as carbon dioxide and nitrogen from natural gas is a technical challenge and one of the major concerns in natural gas treatment process. In this study, adsorption of CH4, N2, and CO2 on the Faujasite (FAU) zeolite has been studied using molecular dynamics simulation at temperatures of 293, 308, and 323 K and pressures up to 1 MPa. COMPASS force field was used to model the interactions between zeolite and guest molecules. Ewald and atom-based summation methods were used for the calculation of electrostatic and van der Waals forces, respectively. Simulated results were modeled using Langmuir, Freundlich, Toth, and Sips adsorption isotherms. Sips isotherm for CO2, and Toth isotherm for CH4 and N2 pure compounds showed the best performance. Heat of adsorption for CH4, CO2, and N2 were calculated to be −15.48, −24.1, and −13.31 kJ⋅mol−1, respectively. A comparative study showed that the simulation model was successful in predicting the overall trend of the adsorption with acceptable accuracy.