The invention relates to a method for regulating a unit for separating a gas stream, having P adsorbers, where P≥2, each following a PSA-type adsorption cycle with a phase time shift, the method involving the steps of operating the unit according to the nominal cycle when the required flow rate is equal to a nominal flow rate or optionally when the required flow rate is higher than the nominal flow rate, and operating the unit according to the reduced cycle when the required flow rate is lower than or equal to a predetermined flow rate, the predetermined flow rate being lower than the nominal flow rate.

A process and apparatus for producing a hydrogen-enriched product and recovering CO.sub.2 from an effluent stream from a hydrogen production process unit are described. The process utilizes a CO.sub.2 recovery system integrated with a PSA system that produces at least two product streams to recover additional hydrogen and CO.sub.2 from the tail gas stream of a hydrogen PSA unit in the hydrogen production process.

A process and apparatus for producing a hydrogen-enriched product and recovering CO.sub.2 from an effluent stream from a hydrogen production unit are described. The effluent from the hydrogen production unit, which comprises a mixture of gases comprising hydrogen, carbon dioxide, water, and at least one of methane, carbon monoxide, nitrogen, and argon, is sent to a PSA system that produces at least two product streams for separation. The PSA system that produces at least two product streams separates the gas mixture into a high-pressure hydrogen stream enriched in hydrogen, optionally a second gas stream containing the majority of the impurities, and a low-pressure tail gas stream enriched in CO.sub.2 and some impurities. The CO.sub.2-rich tail gas stream is compressed and sent to a CO.sub.2 recovery unit, where a CO.sub.2-enriched stream is recovered. The CO.sub.2-depleted overhead gas stream is recycled to the PSA system that produces at least two product streams.

A three-product PSA system which produces three product streams from a feed gas mixture comprising a light key component, at least one heavy key component, and at least one intermediate key component is described. The three-product PSA system produces a high pressure product stream enriched in the light key component, a low pressure tail gas stream enriched in the at least one heavy key component, and an intermediate pressure vent gas stream enriched in the at least one intermediate key component.

A process and apparatus for producing a hydrogen-enriched product and recovering CO.sub.2 from an effluent stream from a hydrogen production process unit are described. The process utilizes a CO.sub.2 recovery system integrated with a PSA system that produces at least two product streams to recover additional hydrogen and CO.sub.2 from the tail gas stream of a hydrogen PSA unit in the hydrogen production process.

A process and apparatus for producing a hydrogen-enriched product and recovering CO.sub.2 from an effluent stream from a hydrogen production unit are described. The effluent from the hydrogen production unit, which comprises a mixture of gases comprising hydrogen, carbon dioxide, water, and at least one of methane, carbon monoxide, nitrogen, and argon, is sent to a PSA system that produces at least two product streams for separation. The PSA system that produces at least two product streams separates the gas mixture into a high-pressure hydrogen stream enriched in hydrogen, optionally a second gas stream containing the majority of the impurities, and a low-pressure tail gas stream enriched in CO.sub.2 and some impurities. The CO.sub.2-rich tail gas stream is compressed and sent to a CO.sub.2 recovery unit, where a CO.sub.2-enriched stream is recovered. The CO.sub.2-depleted overhead gas stream is recycled to the PSA system that produces at least two product streams.

A method for producing oxygen from air using vacuum swing adsorption by means of a unit including at least two adsorbers each following, with an offset a pressure cycle, with a decompression step including at least a co-current first decompression sub-step for the partial balancing of pressure with the other adsorber which is performing counter-current recompression by means of a balancing valve, and, at least for one cycle out of three, a dead time sub-step which succeeds the first decompression sub-step, the method including a pressure of X bar at the end of the first decompression sub-step for the cycles that do not have a dead time sub-step, and a pressure of X bar at the end of the dead time sub-step, opening the balancing valve identically during the first decompression sub-step and the dead time sub-step, for the cycles that do have a dead time sub-step.

A method for producing oxygen from air using vacuum swing adsorption by means of a unit comprising at least two adsorbers each following, with an offset a pressure cycle, with a decompression step comprising at least a co-current first decompression sub-step for the partial balancing of pressure with the other adsorber which is performing counter-current recompression by means of a balancing valve, and, at least for one cycle out of three, a dead time sub-step which succeeds the first decompression sub-step, the method including a pressure of X bar at the end of the first decompression sub-step for the cycles that do not have a dead time sub-step, and a pressure of X bar at the end of the dead time sub-step, opening the balancing valve identically during the first decompression sub-step and the dead time sub-step, for the cycles that do have a dead time sub-step.

Disclosed herein is a stator plate for a rotary bed PSA apparatus that has an exhaust slot that has first and second sections for receiving blowdown and purge exhaust gas streams, the sections being separated by a flow restriction that restricts but does not full prevent gas flow between the sections, or that has separate exhaust slots for separately receiving the blowdown and purge exhaust gas streams. Also disclosed is pressure swing adsorption (PSA) apparatus including such a stator plate, and a rotary bed PSA process using such an apparatus.

Disclosed herein is a stator plate for a rotary bed PSA apparatus that has an exhaust slot that has first and second sections for receiving blowdown and purge exhaust gas streams, the sections being separated by a flow restriction that restricts but does not full prevent gas flow between the sections, or that has separate exhaust slots for separately receiving the blowdown and purge exhaust gas streams. Also disclosed is pressure swing adsorption (PSA) apparatus including such a stator plate, and a rotary bed PSA process using such an apparatus.