Abstract: Pressure swing adsorption (PSA) assemblies with purge control systems, and hydrogen-generation assemblies and/or fuel cell systems containing the same. The PSA assemblies are operated according to a PSA cycle to produce a product hydrogen stream and a byproduct stream from a mixed gas stream. The byproduct stream may be delivered as a fuel stream to a heating assembly, which may heat the hydrogen-producing region that produces the mixed gas stream. The PSA assemblies may be adapted to regulate the flow of purge gas utilized therein, such as according to a predetermined, non-constant profile. In some embodiments, the flow- of purge gas is regulated to maintain the flow rate and/or fuel value of the byproduct stream at or within a determined range of a threshold value, and/or to regulate the flow of purge gas to limit the concentration of carbon monoxide in a heated exhaust stream produced from the byproduct stream.

Abstract: The present invention generally relates to large capacity (e.g., greater than 350 tons/day O2) vacuum pressure adsorption (VPSA) systems and processes that employ a single train including four beds, at least one feed compressor feeding two beds simultaneously at any given instant in time, and a single vacuum pump. The compressor(s) and the vacuum pump can be utilized 100% of the time. Use of product quality gas for purging is avoided, with about 10-20% improvement in O2 productivity and 5-10% reduction in capital cost expected.

Abstract: PSA process for oxygen production comprising (a) providing an adsorber having a first layer of adsorbent selective for water and a second layer of adsorbent selective for nitrogen, wherein the heat of adsorption of water on the adsorbent in the first layer is ? about 14 kcal/mole at water loadings? about 0.05 mmol per gram; (b) passing a feed gas comprising at least oxygen, nitrogen, and water successively through the first and second layers, adsorbing water in the first layer of adsorbent, and adsorbing nitrogen in the second layer of adsorbent, wherein the mass transfer coefficient of water in the first layer is in the range of about 125 to about 400 sec?1 and the superficial contact time of the feed gas in the first layer is between about 0.08 and about 0.50 sec; and (c) withdrawing a product enriched in oxygen from the adsorber.

Abstract: This invention is to a process for removing dimethyl ether from an olefin stream. The process includes contacting the olefin stream with a molecular sieve that has improved capacity to adsorb the dimethyl ether from the olefin stream. The molecular sieve used to remove the dimethyl ether has low or no activity in converting the olefin in the olefin stream to other products.

Abstract: A gas separation method is provided in which, when separating a first component and a second component from a mixed gas containing a plurality of components by using a pressure swing adsorption method, these components can be efficiently recovered and cost reduction can be achieved. Between an adsorption step and a regeneration process step, which use a first adsorption column containing a first adsorbent on which the first component is less readily adsorbable and the second component is absorbable, and a second adsorption column containing a second adsorbent on which the first component is readily adsorbable and the second component is less readily adsorbable, an equalization depressurization step and an equalization pressurization process step, in which the pressure of the first and second adsorption columns is equalized, is carried out.

Abstract: A first aspect of a process of recovering xenon from feed gas includes: providing an adsorption vessel containing adsorbent having a Xe/N2 selectivity ratio <75; feeding into the adsorption vessel feed gas having an initial nitrogen concentration >50% and an initial xenon concentration ?0.5%; evacuating the adsorption vessel; and purging the adsorption vessel at a purge-to-feed ratio ?10. The final xenon concentration is ?15× the initial xenon concentration. A second aspect of the process includes providing an adsorption vessel containing adsorbent having a Xe Henry's law Constant ?50 mmole/g/atm; feeding into the adsorption vessel feed gas having an initial nitrogen concentration >50% and an initial xenon concentration ?0.5%; heating and purging the adsorption vessel to recover xenon having a final concentration ?15× its initial concentration. Apparatus for performing the process are also described.

Abstract: A method of controlling a gas adsorption apparatus including a sieve bed containing molecular sieve bed material, the bed being cyclically operable in a charge mode to adsorb non-product gas from an air supply thereby to increase the concentration of a product gas in a product gas supply which passes to a product gas line and in a vent mode to desorb the adsorbed non-product gas which passes to a non-product gas line, and there being a passage to permit a restricted amount only of the product gas supply to pass from the product gas supply line to the bed when operating in vent mode, and wherein the method includes operating a variable flow device to permit an increased amount of the product gas supply to pass to the bed when operating in vent mode, under predetermined conditions.

Abstract: Disclosed embodiments address contaminant management challenges that arise during production of desirably contaminant free product fluid in the operation of PSA equipment, and further address the more serious challenges that arise under intermittent operation of PSA equipment. One disclosed embodiment of a PSA apparatus, intended primarily for normal operating cycle speeds of at least 3 cycles per minute, includes a breather fluidly coupled to a feed end of an adsorber with a contaminant-sensitive adsorbent. The breather can be coupled to the feed end through a shutoff valve closed during production and open during shutdown. Other disclosed embodiments of the PSA apparatus used particular sealing strategies for additional sealing of the apparatus, or at least components thereof, from contaminant ingress.

Abstract: A system and a process for recovering high concentrations of methane from crude natural gas and solid waste landfill exhaust gas uses a sequential combination of a pressure swing adsorber unit operation to remove volatile organic compounds from the crude feed gas mixture followed by a membrane separation unit operation. The membrane separation uses a membrane which is selectively gas permeable to reject transmission of methane and thus to produce a permeate depleted in methane relative to the feed mixture. The permeate is also free of volatile organic compounds and is recycled to the pressure swing adsorber unit operation to regenerate saturated adsorbers.

Abstract: A gas drying apparatus is provided having at least two desiccant-containing towers which alternately receive moisture-saturated air from an inlet to be dried during a drying phase, and then receive dry air during a regeneration phase to regenerate the desiccant which had previously adsorbed moisture from saturated air during the drying phase. The apparatus diverts a portion of dry air flowing along one of two flow paths including a first flow path having a heater and a pulse purge regeneration control valve for selectively enabling delivery of heated dry air to the tower being regenerated, and a second flow path which bypasses the first flow path and includes a bypass valve for selectively permitting delivery of unheated dry air to the tower being generated so as to cool the desiccant therein. A temperature sensing arrangement is provided for monitoring and maintaining the internal temperature of heated dry air delivered into the tower being regenerated.

Abstract: Product gas (Gpro) is separated from material gas (Gmat) by a PSA process utilizing a plurality of adsorption towers (A-C) each loaded with an adsorbent. The separation of the product gas (Gpro) is performed by repeating a cycle comprising an adsorption step, a decompression step, a desorption step, a cleaning step and a pressurization step. In the decompression step, remaining gas (Grem) as cleaning gas is introduced from one adsorption tower (C) to another adsorption tower (B). The amount of the remaining gas (Grem) introduced is 2 to 7 times the volume of the adsorbent loaded in the adsorption tower (B) as converted into volume at common temperature and under atmospheric pressure. To remove both of carbon monoxide and carbon dioxide from the material gas (Gmat) by a single kind of adsorbent, use is made of zeolite having a faujasite structure with a Si/Al ratio lying in a range of 1 to 1.5 and a lithium-exchange ratio of no less than 95%.

Abstract: A gas concentrating method and apparatus is provided in which equalization is accomplished below two sieve beds, to thereby save compression energy, to reduce exit noise, and to obtain a gas whose gas purity with respect to an amount of flow has been enhanced. The gas concentrating method makes two sieve beds communicate with each other at their bottoms when a pressure difference between a pressurized pressure and a decompressed pressure is maximized in the multi-bed type sieve beds which alternately operate between pressurization and decompression, to equalize an internal pressure in the sieve beds. The gas concentrating apparatus includes a compressor (50), sieve beds (60-1, 60-2), solenoid valves (40-1, 40-2), an orifice (90), check valves (90-1, 90-2), a storage tank (100), a pressure controller (70), a flow meter (80), a controller (110), and a muffler (20).

Abstract: Rapid cycle pressure swing adsorption processes, systems and apparatus for the separation of a multi-component feed gas mixture by selectively adsorbing at least one more readily adsorbable component in a bed of adsorbent material are provided.

Abstract: CMS adsorbents having suitable indexes are used to improve greatly the performance of nitrogen-producing apparatuses where nitrogen is obtained from the air with a PSA method, so as to improve the efficiency of nitrogen production. A nitrogen PSA apparatus is formed with two adsorbing columns where an adsorption step and a regeneration step are performed alternatively and periodically. The adsorption step is for adsorbing oxygen and conducting nitrogen to a product tank with the supply of compressed air from an air compressor, and the regeneration step for releasing the adsorbed gas after the adsorption step. The adsorbing columns are filled with a carbon molecular sieve (CMS) that selectively adsorbs oxygen as an adsorbent. The CMS adsorbs an oxygen/nitrogen amount of 50% of the saturated adsorption amount with a period TO/TN starting from oxygen/nitrogen supply, wherein TO is 5˜10 seconds and TN is larger than TO by more than 41 times.

Abstract: A carbon dioxide (CO2) adsorption membrane or bed is operative to separate metabolic CO2 from an exhaust stream from a breathable atmosphere which is discharged from a closed habitable environment. The habitable environment is in a low ambient pressure surrounding. A portion of the scrubbed exhaust gas stream is diverted from the habitable environment and passed through a desorption chamber. The desorption chamber is open to the low ambient pressure surrounding to maintain a pressure which is slightly greater than the pressure in the ambient surrounding so that the desorption chamber gas stream will exit the system into the ambient surroundings. When the diverted exhaust gas enters the low pressure desorption pressure chamber its CO2 partial pressure content is reduced. The reduced CO2 partial pressure content of the gas stream in the desorption chamber enables the desorption chamber gas stream to remove CO2 from the adsorption membrane or bed.

Abstract: A pressure swing adsorption process for recovering a less readily adsorbable component from a feed gas mixture comprising at least one less readily adsorbable component and at least one more readily adsorbable component. The process utilizes a plurality of adsorbent beds, each bed having a feed end and product end, wherein the process includes the gas transfer steps of (1) transferring gas from the product end of the bed to the product end of another bed; followed by (2) withdrawing waste depressurization gas from the feed end of the bed while continuing to transfer gas from the product end of the bed to the product end of another bed; (3) during either or both of (1) and (2), transferring gas from the feed end of the bed to the feed end or ends of the one or more other beds; and (4) prior to (1), transferring gas from the product end of the bed at a higher pressure to the product end of another bed at a lower pressure.

Abstract: In a process for the production of a polyolefin, an olefin monomer is polymerised said polyolefin and residual monomer is recovered. A gas stream comprising the monomer and nitrogen is subjected to a PSA process in which said monomer is adsorbed on a periodically regenerated silica gel or alumina adsorbent to recover a purified gas stream containing said olefin and a nitrogen rich stream containing no less than 99% nitrogen and containing no less than 50% of the nitrogen content of the gas feed to the PSA process.

Abstract: The invention relates to ammonia synthesis loops containing gases, which do not react and would accumulate if they were not purged out. By the present invention ammonia in a purge gas is recovered by an absorption agent operating at the full synthesis loop pressure. The absorption agent is chosen in such a way that the ammonia can be removed again by passing a gas comprising hydrogen and nitrogen through it at the same elevated pressure as the loop pressure. This enables the adsorption agent to be regenerated by fresh synthesis gas coming from the synthesis gas compressor just before this gas enters the synthesis loop. Thereby, the regeneration requires an absolute minimum of energy consumption and equipment.

Abstract: A gas transfer segment of a vacuum swing adsorption process cycle utilizing multiple parallel adsorbent beds which undergo cyclic process steps to separate the components of a feed gas mixture, each bed having a feed end and a product end, wherein the gas transfer segment comprises a step of withdrawing a waste gas stream from the feed end of a first bed, withdrawing a transfer gas from the product end of the first bed and introducing the transfer gas into the product end of a second bed, and withdrawing a waste gas stream from the feed end of the second bed.

Abstract: A pressure swing adsorption process for the separation of impurities such as nitrogen and carbon dioxide and recovery of hydrocarbons from a natural gas stream utilizes two separate adsorption systems, the first containing an adsorbent selective for nitrogen, carbon dioxide or both and the second containing a hydrocarbon-selective adsorbent. In the process, the natural gas stream is passed through a first adsorbent to form a product stream enriched with methane and to adsorb nitrogen and/or carbon dioxide and which further co-adsorbs at least a portion of the hydrocarbons contained in the feed stream. The hydrocarbons are recovered by passing a low pressure waste stream from the first pressure swing adsorption stage which contains co-adsorbed nitrogen and/or carbon dioxide and hydrocarbons and directing the waste stream to the second pressure swing adsorption stage to adsorb the hydrocarbons and produce a product stream enriched in nitrogen and/or carbon dioxide.

Abstract: A pressure swing adsorption process which comprises introducing a feed gas mixture into an inlet of an adsorber vessel during a feed period, wherein the feed gas mixture contains a more strongly adsorbable component and a less strongly adsorbable component and the adsorber vessel contains a bed of adsorbent material which selectively adsorbs the more strongly adsorbable component, and withdrawing a product gas enriched in the less strongly adsorbable component from an outlet of the adsorber vessel during at least a portion of the feed period, wherein a dimensionless cycle-compensated mass transfer coefficient defined as K tfeedVads/Vfeed is maintained in the range of about 23 to about 250.

Abstract: A pressure swing adsorption process wherein a constant flow of feed gas and product gas is maintained to and from a pressure swing adsorption installation. A part of repressurization is carried out by a product gas split-off, in three stages, with an additional pressure equilibration step between two adsorbers during the second of the three stages, thereby cyclically fluctuating one of the number of adsorbers receiving feed gas during some period. In addition, either combined herewith or not, in case of the use of a higher purge gas pressure, is the return to a regenerated adsorber of a least impure part of the offgas, driven by its initially higher pressure. The result is an increased product recovery efficiency and an improved flexibility of functioning of the installation.

Abstract: A compact multiple bed pressure swing adsorption apparatus to produce a high concentration of oxygen efficiently and at minimum noise levels by using inactive pressurized adsorber beds to purge adsorbed nitrogen.

Abstract: A component gas concentrator includes an air compressor, an air-tight first container containing a molecular sieve bed, the first container in fluid communication with the compressor through a first gas conduit, and an air-tight second container in fluid communication with the first container through a second gas conduit. A gas flow controller such as PLC controls actuation of valves mounted to the gas conduits.

Abstract: A pressure swing adsorption process for recovery of a more readily adsorbable component, such as nitrogen, and a larger amount of a less readily adsorbable component, such as oxygen, from a feed gas mixture, such as air, wherein the ratio of nitrogen to oxygen is less than about 3:1 and the ratio of the co-purge:feed gas of the process is maintained at less than about 1.15:1.

Abstract: This invention provides a two bed pressure swing adsorption process for recovering a primary gaseous component at a purity of over 99% from a feed gas comprising the primary component and one or more impurities.

Abstract: An improved pressure swing adsorption process and system for producing a high recovery of a highly purified product gas, such as argon, from a feed gas stream containing the product gas and impurity gases employs first and second adsorption stages with beds for adsorbing impurity gases. The system and process provides for sequential steps of: feed pressurization; simultaneous feed pressurization and product pressurization; adsorption; adsorption and purge; adsorption in the absence of purge; pressure equalization between beds; evacuation and depressurization of adsorbent bed; evacuation with product purge; evacuation without purge; and pressure equalization between beds.

Abstract: A component gas concentrator includes an air compressor/vacuum pump, an air-tight first container containing a molecular sieve bed, the first container in fluid communication with the compressor/vacuum pump through a first gas conduit, and an air-tight second container in fluid communication with the first container through a second gas conduit. A gas flow controller such as PLC controls actuation of valves mounted to the gas conduits.

Abstract: Disclosed is a novel pressure swing adsorption (PSA) pre-purification process for a feed gas prior to its introduction into a cryogenic distillation unit. The PSA process uses in a multi-bed adsorbent system the steps, performed in a cyclical manner, of feed, blowdown, purge and repressurization. Optionally, a pressure equalization step is employed in the process. The resulting process provides for continual repressurization during the cycle and a constant flow rate of purified feed gas to the distillation unit.

Abstract: A pressure swing adsorption process includes providing a pressure swing adsorption apparatus having six beds, and equalizing a pressure of each of the six beds in four steps, wherein at all times during the process, at least one of the six beds is providing offgas. The process is particularly suitable for purifying hydrogen from a feed gas mixture containing hydrogen and at least one of methane, carbon dioxide, carbon monoxide, nitrogen and water vapor.

Abstract: A process is provided for the concentration and recovery of propylene from propane by a pressure swing adsorption (PSA) process using an adsorbent comprising AlPO-14. A PSA process is used to remove propylene from a C3 hydrocarbon stream comprising propylene and propane. The PSA process of the present invention can be employed in petroleum refining and petrochemical processes to purify and separate propylene from mixtures of propylene and propane without fractionation.

Abstract: A molecular sieve type gas separation apparatus (10) for separating product gas from a gas supply (14) includes at least one sieve bed (11-13) which during an adsorption charge phase of a cycle, adsorbs non product gas in the gas supply (14), and in a desorption regeneration phase of the cycle desorbs the previously adsorbed non product gas. The apparatus further includes an outlet (18) to which product gas is delivered during the adsorption charge phase, and an outlet (31) for non product gas during the desorption regeneration phase. A sensor (36) responsive to the concentration of a constituent in the product gas, and a control (20) to switch the apparatus (10) between the adsorption charge and desorption regeneration phases are further provided. The control (20) is adapted to adjust the duration of adsorption charge phase relative to the duration of the desorption regeneration phase in each cycle.

Abstract: A method of removing individual gas components of a mixture of gases within a controlled environment container uses apparatus which comprises first and second chambers which are arranged in parallel for the gas mixture to flow through them from their inlet ends to their outlet ends. The chambers contain adsorbent material with different affinities for the gas components of the mixture. The method comprises supplying the gas mixture to the first chamber so as to pressurize it while allowing a purge stream to flow from the outlet end of the first chamber to the second chamber to purge adsorbed gas from the adsorbent material in the second chamber. A purge pulse of gas is then supplied from the outlet end of the first chamber to the second chamber to purge adsorbed gas from the adsorbent material in the second chamber, the rate of flow of the purge stream being less than that of the purge pulse.

Abstract: A pressure swing adsorption cycle in which a regeneration phase is terminated by at least one final step in which a residual gas is withdrawn counter-current to the adsorber (1 to 3). A variable portion of the residual gas is recycled, representing from 0 to 30% of the flow of the purified gas product, into the impure gas to be treated, the rest of this residual gas constituting a purge. The duration of the cycle is reduced when this recycling is carried out, the more so as the recycle flow rate is the greater. The cycle has particular application in the production of hydrogen, helium or neon.

Abstract: Substantially all of the carbon dioxide is removed from a gas containing up to about 1% by volume carbon dioxide by subjecting the gas to a pressure swing adsorption process using a two layer adsorption system, wherein the first layer contains activated alumina and the second layer is a zeolite or a combination of zeolites having a silicon to aluminum atomic ratio of at least 1.5. The process is particularly suitable for removing substantially all carbon dioxide and water vapor contained in air prior to subjecting the air to cryogenic distillation.

Abstract: A method and apparatus for operating a pressure swing adsorption process is disclosed that may utilize only a single adsorption stage yet still produce a continuous stream of a concentrated fluid. A portion of the enriched fluid produced during the adsorption cycle in an adsorption chamber is used to purge the adsorption chamber.

Abstract: The flow of gas between two vessels, each of which undergoes cyclic changes in gas pressure, is controlled by two check valves installed in parallel between the vessels. The first check valve allows gas to flow from the first vessel to the second vessel when the differential pressure between the vessels exceeds a first value, and the second check valve allows gas to flow from the second vessel to the first vessel when the differential pressure between the vessels exceeds a second value. The gas flow control method is particularly useful in pressure swing adsorption processes.

Abstract: A process for the separation/recovery of gases is described where the desired component to be separated from the gaseous mixture is present in low/very low molar amount and/or low/moderate pressure, the process comprising contacting the gaseous mixture with a separation membrane unit containing high permeability/medium selectivity membranes which separate the feed stream into a permeate stream, enriched in the desired component and at a lower pressure and a retentate stream lean in the desired component and at a higher pressure. The retentate stream is made to convey its pressure to the permeate stream which then is directed to an adsorption PSA unit for further purification of the permeate stream so that the effluent stream from the PSA unit which contains the purified component has a purity of up to 99.90%.

Abstract: Pressure swing adsorption separation of a feed gas mixture, to obtain a purified product gas of the less strongly adsorbed fraction of the feed gas mixture, is performed in a plurality of preferably an even number of adsorbent beds, with each adsorbent bed communicating at its product end directly to a variable volume expansion chamber, and at its feed end by directional valves to a feed compressor and an exhaust vacuum pump. For high frequency operation of the pressure swing adsorption cycle, a high surface area layered support is used for the adsorbent. The compressor and vacuum pump pistons may be integrated with the cycle, reciprocating at twice the cycle frequency. Alternative configurations of the layered adsorbent beds are disclosed.

Abstract: The cycle employed is of the transatmospheric type with the use of a production buffer tank (C1), and with a purge/elution phase close to the low pressure in which gas output by another adsorber in the first cocurrent decompression phase is introduced in countercurrent into the adsorber (A, B) and, simultaneously, the countercurrent pumping is continued. During the production step, the oxygen produced is also sent into an auxiliary tank (C2), and the gas contained in this auxiliary tank is, with regard to the adsorber, used solely during a fraction of the pressurization phase of the adsorber.

Abstract: A method and apparatus for operating a pressure swing adsorption process having an adsorption zone is disclosed that may utilize only a single adsorption stage. The purge cycle is automatically commenced by a pressure build up in the enriched fluid vented from an adsorption zone.

Abstract: A method and apparatus for operating a pressure swing adsorption process is disclosed that may utilize only a single adsorption stage yet still produce a continuous stream of a concentrated fluid.

Abstract: In a gas refining method using a PSA method, a cleaning step is divided into a preparatory cleaning step and a substantial cleaning step, and an exhaust gas (particularly a high concentration gas obtained in the latter half is effective) obtained in the substantial cleaning step is used as a gas to be admitted into an adsorption column in the preparatory cleaning step. This method is employed, for example, to refine carbon monoxide from a material gas containing carbon monoxide. Accordingly, the gas refining method using the PSA method can ensure a specified amount of collected gas product without resulting in an increase in the amount of adsorbent even if a low concentration material gas is used.

Abstract: A process for controlling the atmosphere in a container including the steps of passing a pressurized portion of the atmosphere serially through a plurality of separate but inter-communicating adsorbent beds which selectively adsorb water vapor, ethylene, carbon dioxide and nitrogen from the compressed atmosphere, then isolating the ethylene-selective adsorbent and desorbing ethylene therefrom, then desorbing nitrogen from the nitrogen-selective adsorbent and purging the carbon dioxide-selective bed, the ethylene-selective bed and the water vapor-selective bed with the desorbed nitrogen, and returning the purge and purged gas mixture to the container.

Abstract: In the steam reforming of hydrocarbon, particularly methane, under elevated temperature and pressure to produce hydrogen, a feed of steam and hydrocarbon is fed into a first reaction volume containing essentially only reforming catalyst to partially reform the feed. The balance of the feed and the reaction products of carbon dioxide and hydrogen are then fed into a second reaction volume containing a mixture of catalyst and adsorbent which removes the carbon dioxide from the reaction zone as it is formed. The process is conducted in a cycle which includes these reactions followed by countercurrent depressurization and purge of the adsorbent to regenerate it and repressurization of the reaction volumes preparatory to repeating the reaction-sorption phase of the cycle.

Abstract: A molecular sieve type gas separation apparatus (10) for separating product gas from a gas supply (14) includes at least one sieve bed (11-13) which during an adsorption charge phase of a cycle, adsorbs non product gas in the gas supply (14), and in a desorption regeneration phase of the cycle desorbs the previously adsorbed non product gas. The apparatus further includes an outlet (18) to which product gas is delivered during the adsorption charge phase, and an outlet (31) for non product gas during the desorption regeneration phase. A sensor (36) responsive to the concentration of a constituent in the product gas, and a control (20) to switch the apparatus (10) between the adsorption charge and desorption regeneration phases are further provided. The control (20) is adapted to adjust the duration of adsorption charge phase relative to the duration of the desorption regeneration phase in each cycle.

Abstract: The device comprises an adsorber (1) and three outlet capacities (2-4), first (8, 9) and second (10, 11) structure to establish bidirectional communication between the adsorber and the elution capacity (2) and the repressurization capacity (3), respectively, and third structure (14A, 15; 16) to establish unidirectional communication from the adsorber to the production capacity (4).

Abstract: A rapid pressure swing adsorption oxygen concentrator is provided having a plurality of at least three sieve beds cycled in sequence such that each is pressurized during one segment of a cycle and depressurized during a plurality of segments of a cycle while the other sieve beds are being sequentially pressurized. Preferably, approximately six sieves are provided and pressurized in sequence, with each being pressurized for approximately 60.degree. of the cycle and depressurized for from about 270.degree. to 300.degree. of the cycle. Each sieve is thereby pressurized for about one to two seconds and depressurized for about five to ten seconds. By utilizing the ability of the sieve material to adsorb faster than it can desorb gas, high output of up to 96% pure oxygen results with a low sieve volume and low power consumption.

Abstract: A method is provided for removing water, carbon monoxide and carbon dioxide out of a gas, such as air, by passing the gas through a packed column so that the gas sequentially contacts a catalyst consisting of platinum or palladium and at least one member selected from the group consisting of iron, cobalt, nickel, manganese, copper, chromium, tin, lead and cerium wherein the catalyst is supported on alumina containing substantially no pores having pore diameters of 110 Angstroms or less under conditions which oxidize the carbon monoxide in the gas into carbon dioxide; an adsorbent selected from the group consisting of silica gel, activated alumina, zeolite and combinations thereof under conditions in which water is adsorbed and removed from the gas and an adsorbent selected from the group consisting of calcium ion exchanged A zeolite; calcium ion exchanged X zeolite; sodium ion exchanged X zeolite and mixtures thereof under conditions which carbon dioxide is adsorbed and removed from the gas.

Abstract: The present invention relates to the recovery of low purity oxygen gas from the top of an adsorber vessel into a receiver tank to be used as a purge reflux gas. Recovery of void gas results in improved process efficiency. The invention may also employ a simultaneous evacuation from the top of the adsorber to remove the lower purity void gas while the main waste evacuation step is conducted. This simultaneous co-current top void gas recovery and counter-current waste evacuation from both ends of the adsorber allows for an overall increase in product recovery of between 3-5% over conventional processes.