Membrane Air Separation Process Simulation: Insight in Modelling Approach Based on Ideal and Mixed Permeance Values

Abstract

The presented work aims to study the gas transport characteristics of polymeric hollow-fiber gas separation membranes. The study focused on examining the gas transport characteristics of polymeric hollow-fiber gas separation membranes using materials such as polysulfone (PSF), polyphenylene oxide (PPO), polyetherimide (PEI), and polyetherimide with polyimide (PEI+PI) for the separation of air mixtures. The permeance values of pure gases O2 and N2and the mixed permeances of oxygen and nitrogen during air separation were obtained. Membrane permeance was measured using an analytical setup combined with a mass spectrometer on membrane modules with different effective membrane areas. Mathematical models of the gas separation process built because of these values show significant discrepancies. To obtain a gas mixture with 95 mol.% nitrogen from the air, considering the mixture permeance, 15.8% more PSF membrane area is required than considering the permeance of pure gases. For a PPO membrane, this value is 13.9%; for PEI, 19.8% less area is required, and for PEI+PI, 15.9% less. In the design of industrial or semi-industrial membrane installations, such discrepancies can lead to significant technical and economic errors.

Keywords

• air mixture separation
• membrane gas separation
• mixture permeance
• process modeling