PROCESS FOR SEPARATING METHANE USING PERMEABLE MEMBRANE

摘要

A process for separating methane from a gaseous mixture containing methane and carbon dioxide by concentration is disclosed, which comprises contacting said gaseous mixture with a membrane comprising a film of a polyimide resin having a repeating unit represented by formula (I): (I) wherein R1 represents a divalent aromatic, alicyclic or aliphatic hydrocarbon group, or a divalent organic group composed of these hydrocarbon groups linked via a divalent organic linking group. The membrane exhibits excellent selective permeability to carbon dioxide, enabling efficient and stable separation of methane.