Patent ID: 6141990
Filing Date: 2000-11-07
Classification: F25J

Abstract:
Process for separating air by cryogenic distillation in a plant comprising a column system in which:a) at least two air streams (6, 7, 7A) are cooled in an exchange line (1) and are sent to a column (3) of the system,b) the air is separated in the column into an oxygen-enriched fraction and a nitrogen-enriched fraction,c) a liquid stream (16) is drawn off from a column (4) of the system and vaporizes in the exchange line,d) a first air stream (6) exchanges heat in the heat-exchange line with the liquid which vaporizes,e) a second air stream (7, 7A) is drawn off from an intermediate level in the exchange line, characterized in that the second air stream is sent from the exchange line to the column system without being expanded.