Gas permeation measurement under defined humidity via constant volume/variable pressure method

Many industrial gas separations in which membrane processes are feasible entail high water vapour contents, as in CO2-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 CO2 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], [2], [3] and [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).

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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 CO2/N2 separation performance of Pebax MH1657 at high humidity.