Abstract: A plant for producing an argon-rich stream from a mixture formed by a purge fluid in an ammonia production plant comprises: at least one phase separator; a methane scrubbing column; a methane separation column; a nitrogen/argon separation column; a line for sending the mixture into at least one phase separator, to produce at least a hydrogen-enriched gas and a hydrogen-depleted liquid; a line for sending at least a portion of the hydrogen-depleted liquid into the bottom of the methane scrubbing column, to form an overhead gas and a bottoms liquid; a line for sending at least a portion of the bottoms liquid from the methane scrubbing column to the methane separation column, to produce a methane-enriched bottoms liquid and a methane-depleted overhead gas; a line for sending at least a portion of the methane-depleted overhead gas to the nitrogen/argon separation column, to form a nitrogen-enriched fluid as overhead of said column; a line for withdrawing an argon-rich liquid as bottoms of said column, serving as

Abstract: An apparatus and to a method for producing krypton and xenon by separating air by cryogenic distillation and in particular to a method for separating gasses from air using internal compression (in which the gaseous oxygen is produced by vaporization under pressure in the exchange line) where a krypton/xenon mixture is extracted is provided.