Permeation of Ternary Mixture Containing HS, CO and CH in Aquivion Perfluorosulfonic Acid (PFSA) Ionomer Membranes.

Aquivion E87-12S Perfluorosulfonated acid ionomer material (PFSA) has been studied as a membrane technology for natural gas sweetening from CO, HS due to its interesting chemical and mechanical stability and good separation performance for polar compounds in humid environments. In the present work, permeation of the HS/CO/CH ternary mixture in this short-side PFSA chain was investigated at pressures up to 10 bar, temperatures up to 50 °C, and in a range of relative humidity (RH) from 20% to 90%. The results obtained confirm the strong dependence of Aquivion on water activity and temperature, and its ability to separate gases based on their water solubility without substantial differences between pure and mixed gas experiments. Indeed, even when tested in ternary mixture, the permeation behavior remains similar to that observed for pure components and binary mixtures. In particular, the permeability of HS is higher than that of CO and methane CH, reaching values of 500 Barrer at 50 °C and 80% RH, against 450 and 23 Barrer for the other two gases respectively. Additionally, when tested at higher pressures of up to 10 bar under humid conditions, the membrane properties remained largely unchanged, thus confirming the overall stability and durability of Aquivion E87-12S in acid environments.