Isothermal and non-isothermal molecular gas transport in model non-homogeneous porous adsorbents

Abstract

The evaluation of isothermal and non-isothermal transport parameters for dilute gases in axially or radially non-homogeneous porous adsorbing diaphragms has been considered on the basis of the molecular transport approach of Nicholson and Petropoulos. The behaviour of model porous adsorbents with realistic axial or radial variation in porosity have then been considered and the salient features of the deviations from homogeneous medium behaviour have been investigated and illustrated with suitable examples. Analogies and differences between the effects of non-uniform porosity and of non-ideal pore structure are discussed. Particular attention has been paid to the effect of axially non-uniform porosity on the evaluation of heats of transport by means of integral-type experiments. The results obtained are of particular significance for the interpretation of experimental results.