Process for the production of a gas having a substantial oxygen content

Claim 1

Process for the production of a gas with substantial oxygen content at a flow higher than 60 T/day by adsorption of nitrogen present in the air, of the type where, in a plurality of n adsorbers, there is successively provided, cyclically according to a period T, on each of said adsorbers, with dephasing T/n from one adsorber to the following one: a) a step of co-current production of oxygen, having a duration x, at a pressure at least equal to atmospheric pressure, with introduction of air at least during a substantial portion of said production step; b) a step of depressurization, comprising at least in the last part thereof, a counter-current depressurization until reaching a sub-atmospheric pressure obtained by pumping; said pumping being followed, optionally, by a flushing-elution through counter-current flow of oxygen enriched gas; the minimum cycle pressure reached during said pumping step being P m ; c) a step of repressurization comprising at least a phase of counter-current repressurization with oxygen enriched gas characterized by the combination of the following steps: d) the number of adsorbers is at least 3 and the number of adsorbers in simultaneous production is at least 2; e) the duration of the production step is longer than dephasing T/n; f) the sum of the durations of counter-current depressurization and the optional flushing-elution is at most equal to the duration of the production step; and g) the step of pumping according to b) is carried out by means of "k" systems of pumping (k≧1), each being adapted to a level of partial depressurization and exerting its action successively on a same adsorber during a pumping of duration y, so that ##EQU2## with "k" lower by at least one unit than the maximum number of adsorbers in simultaneous production during at least a fraction of the time interval T/n.