Prediction of CO2 and H2 solubility, diffusion, and permeability in MFI zeolite by molecular dynamics simulation

Molecular dynamics simulation has been employed to calculate the amounts of solubility, diffusion coefficient, and permeability for the pure and volumetric binary mixture of CO2 and H-2 in MFI (Mobil-FIve) zeolite and the effect of pressure and temperature on the observed transport properties. It has been found that the amount of carbon dioxide adsorption is much more than the amount of hydrogen adsorption and MFI zeolite adsorbs higher amount of both gases with pressure enhancement and temperature reduction. The MSD (mean square displacement) value for the hydrogen is much higher than that of carbon dioxide. The variation of the diffusion coefficient of carbon dioxide and hydrogen gas with pressure does not obey a certain trend, but temperature enhancement has a direct effect on the diffusion coefficient of both gases. It is also noticeable that the diffusion coefficient of hydrogen molecules in the gaseous mixture is lower than that in pure state, and vice versa is true for carbon dioxide. The CO2 permeability decreases with increasing pressure, but H-2 permeability is not affected by the pressure. The permeability of CO2 molecules decreases and the permeability of H-2 molecules increases with increasing temperature.

Automated summary

The study found that in MFI zeolite, the adsorption of CO2 and H-2 increases with increasing pressure and decreasing temperature. The diffusion coefficient of hydrogen is much higher than that of carbon dioxide, and temperature has a direct impact on the diffusion coefficient of both gases. The diffusion coefficient of hydrogen in the gas mixture is lower while that of carbon dioxide in pure state is lower.