(618e) Advancing Material Design Towards Enhanced Sour Gas Separations

The bulk removal of hydrogen sulfide (H₂S) from natural gas remains an operationally energy and cost intensive separation challenge. Polymeric membranes offer a compact and passive pretreatment step to reduce the burden of traditional amine absorption separation techniques. However, a lack of fundamental research on membrane materials for sour gas separations limits the industrial viability of such hybrid separation systems. Recent work at Aramco’s sour gas testing facility has investigated novel membrane materials across 10 polymer families, tailored for harsh H₂S separations. This talk explores the fundamental trends observed in material transport properties and delves deeper into three particular regions of interest within the sour gas transport performance map. Specifically, simultaneously high H₂S/CH₄ and CO₂/CH₄ selectivities are achieved by novel poly(ethylene glycol)- and polyimide-derived polymers, ultrahigh H₂S/CH₄ selectivities are achieved by modified Pebax and PEG hydrogels, and high permeabilities and stability are achieved by alkoxysilanated polynorbornenes. A common strategy for improving sour gas separation performance across all studied polymer classes involves improving the polymer affinity for H₂S by incorporating polar moieties such as alkoxysilyl, amine, or ether content. Themes of plasticization, solubility versus diffusion controlled separations, and tradeoffs in transport properties are discussed throughout.