The present invention generally relates to a process for responding to feed flow variations by changing the process cycle and thereby increasing the productivity and capacity of the system significantly over constant process systems. This increases the flexibility a PSA system for customers that do not require a constant or uniform product flow rate and/or for processes and applications that experience feed streams that vary in flow, temperature, and/or composition.

A system for pressure swing adsorption including: a plurality of beds each performing at least one of an adsorbing process, a pressure equalizing process, a vacuum process, or a pressurizing process; a supply valve provided in each of the beds and connected to a mixed gas supply unit to supply a mixed gas to the bed; a discharge valve provided in each of the beds and connected to a hydrogen gas discharge unit to discharge hydrogen generated in the bed; a vacuum valve provided in each of the beds and connected to a vacuum pump so as to be open to the vacuum pump during the vacuum process of the bed; and a control unit that controls the supply valve, the discharge valve, and the vacuum valve to allow each of the beds to perform the adsorbing process, the pressure equalizing process, the vacuum process, or the pressurizing process.

A method for retrofitting a system for recovering paraxylene. The system is retrofitted with a pressure swing adsorption unit and a second isomerization reactor. The retrofit lowers the variable cost of the plant, while providing the opportunity to maintain existing equipment and furnace and refrigeration duty.

A unit for purifying a gas mixture by adsorption, including at least one adsorber having at least one cluster of N identical adsorbent modules operating in parallel, where N2, each cluster of N adsorbent modules includes a common inlet manifold having a straight inlet duct of axis Xe supplying N inlet nozzles Tei, where i ranges from 1 to N, respectively connected to the inlets Ei, where i ranges from 1 to N, of the N modules of the cluster, a common outlet manifold having a straight outlet duct of axis Xs collecting the flow leaving the N outlet nozzles Tsi, where i ranges from 1 to N, respectively connected to the outlets Si, where i ranges from 1, of the N modules of the cluster.

The present invention is directed to an intensified process cycle that utilizes the adsorption beds present to a substantially greater degree allowing the processing of significantly more gas and/or the generation of significantly more product. The elimination of purge steps, reduction in equalization step times, and introduction of overlapping feed and equalization steps which normally cause a degradation in performance for equilibrium-based cycles, frees extra step for other actions to be taken, such as additional equalization steps, etc.

The present invention generally relates to a process that utilizes tunable zeolite adsorbents in order to reduce the bed size for nitrogen removal from a methane (or a larger molecule) containing stream. The adsorbents are characterized by the rate of adsorption of nitrogen and methane and the result is a bed size that is up to an order of magnitude smaller with these characteristics (in which the rate selectivity is generally 30) than the corresponding bed size for the original tunable zeolite adsorbent that has a rate selectivity of >100x.

The present invention generally relates to a pressure swing adsorption process for separating an adsorbate impurity from a feed stream comprising product gas, said process comprising feeding the feed stream to an adsorbent bed at a pressure of from about 60 psig to 2000 psig, wherein said adsorbent bed comprises adsorbent having: An isosteric heat of adsorption of from about 5 kJ/mol to about 30 kJ/mol, as determined by the LRC method, for the adsorbate, and an equivalent 65 kJ/mol or less isosteric heat of adsorption for the product,
wherein the adsorbent has a rate of adsorption for the adsorbate impurity that is at least 10 times greater than the rate of adsorption for the product gas as determined by the TGA method and recovering said product gas with a reduced a level of said adsorbate impurity.

The invention also related to an adsorbent useful in PSA separations, particularly separating N.sub.2 from methane, CO.sub.2 from methane O.sub.2 from N.sub.2 and the like.

An oxygen supplying apparatus includes: an oxygen enriching module including a plurality of oxygen enriching units; a pressure boosting module which receives the oxygen-enriched gas from the oxygen enriching module and boosts pressure of the oxygen-enriched gas; and a controller controlling operations of the oxygen enriching module and the pressure boosting module. The pressure boosting module includes: a low-pressure tank which receives and stores the oxygen-enriched gas from the oxygen enriching module; a pressure booster which boosts pressure of the oxygen-enriched gas discharged from the low-pressure tank; a high-pressure tank stores the oxygen-enriched gas pressure-boosted by the pressure booster; and at least one bypass valve which is provided to a bypass passage for bypassing a portion of the pressure-boosted oxygen-enriched gas stored in the high-pressure tank to the low-pressure tank to regulate bypassing of the oxygen-enriched gas from the high-pressure tank to the low-pressure tank.

A unit for purifying a gas mixture by adsorption, including at least one adsorber having at least one cluster of N identical adsorbent modules operating in parallel, where N2, each cluster of N adsorbent modules includes a common inlet manifold having a straight inlet duct of axis Xe supplying N inlet nozzles Tei, where i ranges from 1 to N, respectively connected to the inlets Ei, where i ranges from 1 to N, of the N modules of the cluster, a common outlet manifold having a straight outlet duct of axis Xs collecting the flow leaving the N outlet nozzles Tsi, where i ranges from 1 to N, respectively connected to the outlets Si, where i ranges from 1, of the N modules of the cluster.

Pressure swing adsorption process for reducing fluctuations in the flow rate of tail gas from the adsorption unit. The flow rate of the stream of blowdown gas is regulated responsive signals from a sensor measuring the pressure and/or flow rate of the tail gas comprising the blowdown gas and purge gas effluent before the tail gas is introduced into a surge vessel.