Process for removing nitrogen

A process for removing a nitrogen-rich fraction from a feed fraction containing essentially nitrogen and hydrocarbons, wherein the feed fraction is partially condensed in one or more heat exchangers and fractionated by rectification in one or more separation columns into a nitrogen-rich fraction and a methane-rich fraction, said process comprising:

• during an interruption in the supply of the feed fraction, said one or more separation columns used for the fractionation by rectification and also said one or more heat exchangers E1 used for partial condensation of the feed fraction and one or more heat exchangers E2 used for cooling and warming of process streams occurring in the fractionation by rectification are kept, by means of one or more differing cooling media, at temperature levels which correspond essentially to the temperature levels during standard operation of said one or more separation columns, said one or more heat exchangers used for partial condensation of the feed fraction, and said one or more heat exchangers used for cooling and warming of process streams occurring in the fractionation by rectification.