Method and apparatus for low-temperature separation of air for the production of nitrogen under elevated pressure by means of a pumped liquid nitrogen.

摘要

The process of the present invention is a cryogenic air separation process with three important features: (1) at least a portion of a nitrogen-rich liquid from the column system is boosted in pressure before being vaporized and delivered as a product; (2) at least a portion of the feed air is at least partially condensed in indirect heat exchange with the boosted pressure, nitrogen-rich stream; and (3) a portion of the liquid nitrogen condensed from the vapor nitrogen from the top of the higher pressure column is returned to the higher pressure column as reflux with the remaining portion being removed from the column system.