Influence of traces of water on adsorption and diffusion of hydrocarbons in NaX zeolite

Measurements have been performed on the influence of a small amount of water on adsorption properties of alkanes (C-3 to C-6) and olefins (C-3 and C-4) in NaX zeolite. Adsorption capacity and heat of adsorption have been measured by a Volume Step method. Kinetics has been measured by Thermal Frequency Response method and the results have been compared with the results obtained by PFG-NMR. It has been found that water reduces the adsorption capacity especially at low adsorbate concentration. The heat of adsorption is slightly reduced by water. The kinetics of alkanes is always reduced by the adsorbed water. On the contrary, the diffusion kinetics of olefins is improved or remains unchanged, depending of the sorbat concentration.