Process to extract nitrogen and oxygen from ambient air by fractionated cryogenic distillation reduces complexity and expense of apparatus

摘要

Oxygen and nitrogen are produced by the fractionated cryogenic distillation of air in a three-column process having a first pressurized column, a secondary column and a low-pressure column. Oxygen and nitrogen are produced by the fractionated cryogenic distillation of air in a three-column process having a first pressurized column (7), a secondary column (8) and a low-pressure column (9). The nitrogen product (266, 267, 57) is drawn in particular from the upper part of the first pressurized column (8) and/or preferably from the upper section of the secondary column (8). Oxygen (34, 35) is drawn in particular from the lower part of the low-pressure column (9) and is warmed by direct heat-exchange (6) with incoming process air.