Intrinsic permeability of refractories from gas permeability measurements: Comparison of results

The gas permeability of porous materials largely depends on pressure, with the intrinsic permeability typically being determined using Klinkenberg's model, which is valid when the gas flows under viscous conditions. However, measurements performed on refractories with the outlet at atmospheric pressure often reveal inertial effects. Therefore, gas permeability is assumed to be flow-rate dependent; an alternative approach is proposed to determine the intrinsic properties using the Forchheimer number. A gas permeameter has been developed to improve measurement accuracy. It allows for the conduction of a test in viscous flow conditions or with inertial effects. The improved gas permeameter was used to compare the different approaches to the evaluation of the intrinsic permeability of four refractory materials with permeabilities ranging from 0.03 to 6 darcies. Combining a modified pressure drop method with Klinkenberg's model proved to be a reliable method for consistently evaluating refractory material permeability.