Purification of gas mixtures based on the removal of small impurities from a counterflow membrane module: engineering calculation method

Abstract

One of the tasks of the membrane gas separation process is the extraction of low-content highly penetrating impurities from gas mixtures.
 The gas separation process is efficiently organized using hollow fiber-type membrane modules.
 In this study, an attempt was made to develop an engineering method for calculating the purification of gas mixtures based on the removal of small impurities from a countercurrent membrane module, which would enable the calculations related to the separation mode using analytical dependencies, without the use of numerical integration procedures and iterations.
 A mathematical model representing the gas separation process from binary mixtures having low content of a highly penetrating component was analyzed to address the challenges related to cleaning, purifying, and drying gas mixtures. Parametric studies related to the process were carried out and an engineering calculation method that enabled calculating separation in the module without using complex, resource-intensive algorithms having analytical formulas was developed herein. During the parametric study, the separation of a binary gas mixture was considered a limiting case. The proposed method was tested with respect to the example of air drying in a module comprising a (polyvinyltrimethylsilane) PVTMS membrane, which was an approximation of a binary mixture. The numerical and analytical results of the calculation are consistent with each other, and the calculation herein based on the developed method requires several orders of magnitude fewer calculations, that can even be performed manually.