Method and device for the production of nitrogen with principles of the pressure above atmospheric phae

摘要

A process and apparatus is provided for the production of nitrogen with over-atmospheric pressure by two-stage rectification of air at low temperatures. Air (1) is compressed (2), pre-purified (4, 6), cooled (33) in heat exchange with products of fractionation, and fed to the rectification device. An oxygen-enriched liquid (19) from the sump of the low-pressure stage (13) is vaporized (15) in contraflow to condensing nitrogen in the top of the low-pressure stage. Nitrogen (27) is extracted from the top of the low-pressure stage and may be mixed with nitrogen (30) from the top of the pressure stage (10). The vaporized oxygen-enriched liquid may be heated and used to regenerate the molecular sieves or screens (4, 6) used for pre-purification. IMAGE