Two-dimensional gas filtration in a bidisperse porous layer under dynamic adsorption and desorption

Abstract

In this research the flow-through porous medium is represented as a system of two types of hydrodynamically connected porous channels with significantly different characteristic diameters. The microporous component of the system, adjacent to both types of channels, is considered impermeable; however, it takes part in adsorption-desorption processes. In a two-dimensional formulation, the following problems are considered: filtration flows emerging during gas injection into the layer, establishment of dynamic gas equilibrium in a sealed layer, and the process of pressure reduction during gas outflow. As indicated by the calculations, significant near-surface pressure gradients with destructive potential arise during intense gas injection into the layer and its outflow. Furthermore, due to the significantly differing permeabilities in the flow-through areas, substantial local pressure drops occur even under relatively weak flows. Depending on the amount of adsorbed gas, these pressure drops can persist for a considerable time, resulting in potential damage to the internal porous structure. The detailing of the pore space provided in this article contributes to a greater physical understanding of the kinetic stage of the mass transfer process in porous media during intense filtration flows.