Abstract
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► A detailed description of a measurement principle for gas permeability under defined humidity. ► Thorough account of device setup and measurement uncertainty calculation. ► Significant change in the CO
2/N
2 separation performance of Pebax MH1657 at high humidity.
Many industrial gas separations in which membrane processes are feasible entail high water vapour contents, as in CO
2-separation from flue gas in carbon capture and storage (CCS), or in biogas/natural gas processing. Studying the effect of water vapour on gas permeability through polymeric membranes is essential for materials design and optimization of these membrane applications. In particular, for amine-based CO
2 selective facilitated transport membranes, water vapour is necessary for carrier-complex formation (Matsuyama et al., 1996; Deng and Hägg, 2010; Liu et al., 2008; Shishatskiy et al., 2010)
[1–4]. But also conventional polymeric membrane materials can vary their permeation behaviour due to water-induced swelling (Potreck, 2009)
[5]. Here we describe a simple approach to gas permeability measurement in the presence of water vapour, in the form of a modified constant volume/variable pressure method (pressure increase method).