Acid Gas Purification Using Silane-Modified Cellulose Acetate Dense Film Membranes

Natural gas is one of the cleanest and most useful of all energy sources, with consumption expected to grow by 39% from 2010 to 2035. Despite its advantages, natural gas can contain large amounts of acid gases (H₂S and CO₂) that require removal before distribution. Typical pipeline specifications in the US require that natural gas be purified below 4 ppm and below 2% for H₂S and CO₂, respectively. Current technologies for removing such impurities are successful but energy intensive. Membrane processes could supplement or replace the current technologies. Only a few studies have considered simultaneous removal of CO₂ and H₂S; moreover, due to the hazardous nature of H₂S, prior studies have generally focused on low concentrations of H₂S.

We present the modification of dense film cellulose acetate (CA) membranes using vinyltrimethoxysilane (VTMS), a technique we refer to as GCV-Modification. It shows significant performance improvements for H₂S and CO₂ removal from aggressive natural gas feeds.