Purification of Aggressive Supercritical Natural Gas Using Carbon Molecular Sieve Hollow Fiber Membranes

In this paper, we describe polyimide-derived carbon molecular sieve (CMS) hollow fiber membranes with CO 2 /CH 4 separation factors ∼60 under a supercritical (1800 psia) natural gas feed comprising 50% CO 2 and 500 ppm highly condensable C 7 hydrocarbons. Long-term tests extending for 200 h proved membrane stability. Temperatures ranging from −50 to 100 °C were also tested, and the membrane showed attractive performance under the diverse conditions studied. With attractive and stable separation performance, the CMS hollow fiber membranes studied in this work can potentially enable next-generation CO 2 removal processes for challenging natural gas feeds.