Method for removing nitrogen

Abstract

A process is described for separating off a nitrogen-rich fraction from a feed fraction containing essentially nitrogen and hydrocarbons, wherein the feed fraction is separated by rectification into a nitrogen-rich fraction and a methane-rich fraction and wherein the methane-rich fraction for the purpose of cold generation is vaporized and superheated at a pressure as high as possible against the feed fraction which is to be cooled. According to the invention the still liquid or partially vaporized methane-rich fraction (5′) is fed to a circulation vessel (D), only the liquid fraction of the methane-rich fraction (5′) occurring in the circulation vessel (D) is completely vaporized, preferably in natural circulation, and the top product (7) of the circulation vessel (D) is superheated (E1).

Dependencies are inferred from the claim text.