Search for a command to run...
One of the most effective and technologically promising ways to separate components of a gas mixture is the use of selective polymer membranes. It is advisable to model and optimize operation of such installations based on fundamental approaches of mechanics of multiphase systems. The aim of this work is to develop a generalized imensionless criterion for evaluating the dominant mechanism of gas separation using selective fiber membrane. An important result is that the same membrane, depending on operating parameters, can function either predominantly in diffusion or filtration mode. The mathematical model underlying the analysis includes system of equations based on the laws of conservation of mass and Darcy’s law for porous medium. The closing relations connecting the component fluxes with their concentrations and pressure drop made it possible by numerical solution to obtain distributions of concentrations of key components (oxygen and nitrogen) along the length of membrane module. A dimensionless criterion is proposed that characterizes the dominant mechanism of mass transfer of gas mixture components through the body of selective membrane. A critical value of 1 is established for introduced criterion, which allows the selection of operating parameters for selective membrane system that guarantees the required mass transfer regime. Calculations have shown that when the value of proposed criterion is less than one, the filtration mechanism of mass transfer prevails, which leads to selective release of the lightest component of the mixture, nitrogen. If the criterion exceeds one, the diffusion mechanism becomes dominant, and the plant effectively separates oxygen.