A Study of the Mass Transfer of CO₂ through Different Membrane Materials in the Membrane Gas Absorption Process

Abstract

The mass transfer of carbon dioxide through hydrophobic membrane materials into aqueous solutions of monoethanolamine has been studied. Microporous polypropylene, polytetrafluoroethylene and polyvinylidene fluoride hollow fiber membranes were compared. Membranes were characterized before and after use and wetting studies showed that the mass transfer resistance increased by 15% for polypropylene after 45 hours. Wetting may be due to membrane degradation as a result of contact with the solvent. This study highlights the need to choose membrane‐solvent systems that utilize a low cost membrane that remains unwetted by the solvent over long periods and when subjected to reasonable solvent‐side pressures.

Keywords:

• Carbon dioxide
• mass transfer
• absorption
• polypropylene
• hydrophobicity
• monoethanolamine

Acknowledgments

The authors would like to thank the Cooperative Research Centre for Greenhouse Gas Technologies (CO2CRC), Particulate Fluids Processing Centre (PFPC) and Australian Research Council (ARC) for financial assistance. Also, the receipt of a Melbourne University Postgraduate Overseas Research Scholarship (PORES) and help from Harald Berwald and the workshop at the University of Regina allowed absorption experiments to be conducted at the International Test Centre for CO₂ Capture, Canada. The authors would also like to acknowledge Paul Pigram and Penelope Hale for assistance provided with XPS analysis and Kang Li and the University of Bath for donation of the PVDF fibers.