Method for separating air by cryogenic distillation in column system, involves withdrawing liquid containing specific mol percent of oxygen from bottom of low pressure column, where liquid is pressurized and vaporized to form gaseous oxygen

摘要

The method involves cooling fraction of compressed air at pressure in a heat exchanger (57), and reducing the pressure of the air to another pressure. Another fraction of the compressed air in the exchanger is cooled and compressed in a booster (15). Flow of oxygen-enriched and nitrogen-enriched stream is sent to a high pressure column (29), and a liquid (52) containing 97 mol percent of oxygen is withdrawn from the bottom of a low pressure column (31). The liquid is pressurized and vaporized to produce gaseous oxygen, where reflux ratio of the low pressure column is greater than 1.5. An independent claim is also included for an apparatus for separating air by cryogenic distillation.