Patent ID: 8794031

Claim:
A method for resolving a hydrocarbon-rich, nitrogen-containing feed fraction ( 1 , 1 ′), comprising: separating the feed fraction ( 1 , 1 ′) by rectification (T 1 , T 2 ) into a nitrogen-enriched fraction ( 5 ) and a hydrocarbon-rich, nitrogen-depleted fraction ( 10 ), wherein the separation by rectification is conducted in a rectification column comprising a preseparation column (T 1 ) and a main separation column (T 2 ), and removing a liquid fraction ( 6 ) from said main separation column (T 2 ) above the feed-in site(s) of a fraction ( 7 , 7 ′, 7 ″) that is removed from said preseparation column (T 1 ) and fed to said main separation column (T 2 ), and said liquid fraction ( 6 ) from said main separation column (T 2 ) is applied to said preseparation column (T 1 ) as reflux.