Enhanced natural gas sweetening with ultralow H2S concentration via polycarbonate-silica mixed matrix membranes

Abstract

Abstract Mixed matrix membranes (MMMs) are brought up as prospecting media to sweeten natural gas in recent decades. But the majority of experiments have conducted on CO2/CH4 gas pair separation and, H2S removal from CH4 through MMMs has been paid less consideration. Thereupon, polycarbonate (PC) permeability and permselectivity as a cheap and abundant polymer and two PC-based MMMs were investigated under various operational conditions for this gas couple. The influence of operational parameters including transmembrane pressure, feed temperature, H2S inlet concentration and physical aging on the permeability of mixed gas and selectivity of the H2S/CH4 pair were assessed. It was observed that addition of silica nano particles causes more H2S permeability and selectivity. As a result, it can be used for methane upgradation. Membranes fabricated of silica modified by PDMS showed the highest permeability of H2S and also the superior selectivity of H2S/CH4. Therefore, it could be possibly applied to mitigation of H2S concentration in the outlet gas stream. Additionally, the two fabricated MMMs demonstrated H2S transport in a facilitative manner.