Effect of pore structure and macroscopic non-homogeneity on the relative gas permeability of porous solids

Abstract

The effect of pore structure on the relative gas permeability, PR, of a mesoporous solid containing a low volume fraction, Vs, of sorbed vapour has been examined by means of simple capillary models consisting of parallel or serial arrays of capillaries of varying radius. These simple models represent the limiting behaviour of a more realistic network model at high or low connectivity, respectively. Certain general results, as well as detailed information about the effect of the shape and width of the radius-distribution function, on the initial slope and shape of the PR(Vs) curve are reported and conclusions are drawn about important aspects of the relative permeability behaviour of random and non-random networks. The effect of macroscopic non-homogeneity of the porous solid, in the form of axially or radially non-uniform porosity, on the initial slope of PR(Vs) curves has also been investigated and shown to be an important factor to be considered in practice.