Membrane separation process modeling for CO₂ partial removal in prepurification of air separation units

Abstract

A novel membrane/adsorption hybrid system was proposed for air prepurification in large scale air separation units. Mathematical models were established for cocurrent and countercurrent flow patterns with crude nitrogen as purge stream to describe the membrane separation performance. The experimental and predicted results are in good agreement confirming the validity of the mathematical models. Effects of membrane properties and operation parameters on O₂ recovery, N₂ recovery, and membrane area requirement were investigated. For countercurrent flow pattern, O₂ recovery and N₂ recovery were larger than 98 and 99%, respectively, and membrane area requirement was less than 0.25 m²/m³•h⁻¹ with feed side pressure of 0.6 MPa and the purge gas/feed gas ratio of 0.2.

Keywords:

• CO₂ removal
• membrane area requirement
• N₂ recovery
• O₂ recovery
• prepurification of air separation
• process simulation

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work is supported by the National Key R&D Program of China (2017YFB0603402), the National Natural Science Foundation of China (21576217), and the Fundamental Research Funds for the Central Universities (xjj2016044).