Abstract: According to this process: the medium pressure column is operated under a pressure which is higher than six bars and is preferably at least equal to about 9 bars absolute; a first vaporization gas which is less volatile than the nitrogen from the top of the medium pressure column is condensed in the vat condenser of the low pressure column; and nitrogen from the top of the medium pressure column is condensed, it is thereafter sent under reflux to the top of the medium pressure column, at a level of the low pressure column located above said vat condenser application to apparatuses for air distillation with double column associated with a gas turbine.

Abstract: Compressed air, feeding a unit for the separation of gases present in air, releases calories to a refrigerating unit which operates by absorption while cooling a flow of liquid in heat exchange relationship with a gas of the apparatus to cool the latter so as to ensure a reduction of the global energy consumption of the apparatus.

Abstract: The apparatus is of the type having a double column and a mixing column. The latter is fed at the bottom portion with auxiliary air that is compressed at a pressure different from that of the mean pressure column, and at the top by means of a liquid withdrawn from the bottom of the low pressure column and pumped at the same pressure as the auxiliary air. Impure oxygen is withdrawn at the top of the mixing column as production gas, and substantially pure oxygen is produced at the bottom of the low pressure column.

Abstract: Oxygen from the bottom of a low pressure column (4) is purified from hydrocarbons in a first auxiliary column (12), and the vapor at the top of this column is distilled in a second auxiliary column (17) heated at the base thereof with air at medium pressure. Ultra-pure oxygen is produced at the bottom of the second auxiliary column. Application in the production of ultra-pure oxygen for the electronic industry.