Effect of Hydrocarbons on the Separation of Carbon Dioxide From Methane through a Polyimide Gas Separation Membrane

Abstract

The removal of carbon dioxide from natural gas by membrane gas separation is an important process in upgrading the gas for consumers. Hydrocarbons associated with natural gas have the potential to influence the CO2 separation performance of membranes. Here, a glassy polymeric membrane of poly (4,4′- hexafluoroisopropylidene diphthalic anhydride-2,3,5,6-tetramethyl- 1,4-phenylenediamine) (6FDA-TMPDA) was exposed to hexane and toluene at different partial pressures in a 90% CH4-10% CO2 gas mixture. The permeability of CO2 and CH4, as well as the selectivity, declined over time as both hexane and toluene competitively sorbed into the membrane. The resulting behavior fit the dual-sorption model ..