Abstract: An alternating pressure apparatus for obtaining oxygen from the air has two adsorbers to which an air blower for adsorption air and a vacuum pump stand for desorption are connected. The vacuum pump stand has two vacuum pumps in tandem. The second vacuum pump in the direction of flow is configured as a rotary piston pump with preliminary inlet cooling for the defined inflow of outside air at atmospheric pressure. The inlet of the second vacuum pump is connected to the outlet of the first vacuum pump without the use of gas cooling by water injection or by a heat exchanger. The alternating pressure apparatus operates with a desorption pressure between 300 mbar and 500 mbar.

Abstract: A process for separating oxygen and nitrogen using an adsorption system comprising at least one main adsorption vessel containing an adsorbent selective for one component and at least one auxiliary adsorption vessel containing an adsorbent selective for the same component, the auxiliary vessel(s) being operated under conditions which result in the production of a product gas of lower purity than the product gas from the main adsorption vessel(s). The lower purity product gas from the auxiliary vessel is used to purge or pressurize the main adsorption vessel(s).

Abstract: A PSA process for the separation of a gaseous flow containing essentially oxygen and nitrogen, such as air, by preferential adsorption of the nitrogen on at least one bed of a thickness (e) of an adsorbent material of mean granulometry (d) in at least one separation zone, in which there is selected a thickness (e) of the adsorbent bed such that: ##EQU1## e and d being expressed in mm.

Abstract: In the pressure swing adsorption of nitrogen from gas mixtures with less polar gas components at temperatures of between 20.degree. and 50.degree. C., wherein the gas mixture is passed through an adsorber which is filled with packings of zeolite pellets and has an inlet zone and an outlet zone, the improvement which comprises providing at least two packings in the adsorber, a packing of Li-zeolite X in the inlet zone of the adsorber and a packing of at least one of Ca-zeolite A and Ca-zeolite X in the outlet zone of the adsorber.

Abstract: This process carries out a cycle on a monoadsorber (1) connected, on the one hand, to at least one container (2, 3) via a line (8, 10) fitted with a variable-opening valve (9, 11) and, on the other hand, to a reversible compression/pumping machine coupled to a speed variator (5). Application in particular to the production of oxygen at a variable flow rate from atmospheric air.

Abstract: This invention relates to a VPSA method for the production of a product that is enriched with a more preferred gas from a mixture of the more preferred gas and a less preferred gas and, preferably to a VPSA method for the production of an oxygen-enriched product from air, using an oxygen-preferential adsorbent under equilibrium conditions. In a preferred embodiment the process uses a desorption purge at a nearly constant pressure that is selected to produce a steady stream of oxygen having a purity from 30% to 60% at a pressure in the range of 60 kPa to 20 kPa.

Abstract: A process and apparatus for separating the components of a gas mixture in a pair of adsorption vessels using a single gas compressor/pump to move gas into and out of the adsorption vessels. The cycle is such that the gas compressor/pump is in continuous operation. The adsorption cycle is non-symmetrical in that the series of steps carried out in one of the adsorbers is not the same as the series of steps carried out in the other adsorber. The apparatus includes an intermediate gas storage container which is used to temporarily store gas removed from the nonadsorbed gas outlet end of the adsorption vessels so that it can be used to partially pressurize the adsorption vessels upon completion of the adsorbent regeneration step of the adsorption cycle.

Abstract: Ozone is recovered from an ozone-oxygen mixture by adsorption using an adsorbent which comprises a zeolite selected from the group consisting of L type zeolite, Y type zeolite, ZSM-5, and mordenite in which at least 90% of the exchangeable cation content is in the ammonium form and the molar ratio of potassium to aluminum is less than about 0.25. Alternatively, a proton-exchanged L type zeolite can be used in which at least 90% of the exchangeable cation content is in the proton form and the molar ratio of potassium to aluminum is less than about 0.25.

Abstract: Krypton present in a trace amount in a gaseous oxygen/nitrogen mixture is effectively enriched by an adsorption/desorption process of the pressure variation mode using a system including at least three fixed bed adsorption columns packed with hydrogenated mordenite. At the end of adsorption operation in one column, a desorbed gas from another column is fed to the one column under substantially the same pressure as the pressure during adsorption operation for fully washing the one column. Thereafter, the one column is subject to desorption operation.

Abstract: A process is provided for selectively removing acid gases from a gas mixture by contacting said gas mixture with an anion exchange resin containing quaternary ammonium functionalities and moderately basic counteranions. The absorption process is reversible and the absorbent can be regenerated using an inert gas purge or by applying a vacuum.

Abstract: A natural gas feed stream containing significant quantities of nitrogen and/or carbon dioxide can be increased to a content of greater than 95 percent by volume of natural gas, and preferably greater than about 98 percent, by passing the natural gas feed stream sequentially through three adsorbent beds that are cycled through seven phases comprising: an adsorption phase to adsorb a first gas, a first depressurization phase to remove feed gas from the voids in the adsorbent bed, a recycle phase to remove a second gas from the adsorbent by the passage of a second depressurization gas therethrough and to produce a recycle gas, a second depressurization phase to reduce the adsorbent bed pressure to about ambient and to produce the second depressurization gas, an evacuation phase where the pressure in the adsorbent is further reduced and an enriched primary gas product stream recovered, a pressurization phase where the pressure in the adsorbent bed is increased using secondary product gas from a bed in an adsorpti

Abstract: A device for separation of gas by adsorption, of the so-called VSA or MPSA type, comprises, between a utilization line (L) and a source (S) of gaseous mixture to be separated, at least one module (M) comprising in series a reversible rotary machine (R), typically a Roots machine, an adsorber (A) and a shut-off valve (V), the rotary machine (R) being alternately actuated, in one direction during a first phase of pressurization and of production and then, in the other direction, during a second phase of depressurization and desorption. Used particularly in the production of small and medium volumes of oxygen in modular installations.

Abstract: In a process of recovering oxygen-enriched gas by pressure swing adsorption with use of adsorbers (A, B) each packed with an adsorbent which selectively adsorbs nitrogen from a gas mixture mainly containing nitrogen and oxygen, recovery of remaining oxygen-enrich gas is fully carried out by pressure equalization between both adsorbers (A, B), and a vacuum pump (8) is always connected to either adsorber (A or B) for continuous evacuation of nitrogen. For this purpose, the pressure equalization between both adsorbers (A, B) is conducted at least in two steps wherein one adsorber (A or B) is pressurized, whereas the other adsorber (B or A) is pressurized, so that recovery of oxygen-enriched gas is possible until there is substantially no pressure difference between both adsorbers (A, B).

Abstract: A pressure swing adsorption process which includes switching a plurality of adsorption columns packed with an adsorbent successively to an adsorption step, a pressure equalization step, an evacuation step, a vacuum purge step, a pressure equalization step and a repressurization step to allow a more strongly adsorbable component gas contained in a gaseous mixture to be adsorbed on the adsorbent and to separate a less strongly adsorbable component gas. The process further includes compressing the thus separated less strongly adsorbable component gas by a product gas compressor to supply it as a product gas.

Abstract: Vacuum pressure swing adsorption (VPSA) processing is carried out employing a processing sequence of ten steps that serves to enhance the productive capacity thereof for air separation and other desirable applications.

Abstract: An apparatus is provided for recovering volatile liquid vapor from an air-volatile liquid vapor mixture. The apparatus includes first and second reaction vessels. Each of these reaction vessel includes a bed of adsorbent having an affinity for the volatile liquid vapor. The apparatus also includes a pump and an absorber for regenerating either bed of adsorbent. Further, the apparatus includes a polisher including a polisher bed of adsorbent having an affinity for the volatile liquid vapor. This polisher bed adsorbs volatile liquid vapor and substantially clean air is exhausted when initially regenerating one of the two beds of adsorbent in the first and second reaction vessels. Still further, the apparatus also includes a cooperating valve and conduit system for interconnecting the other components. Further, the invention relates to a related process for recovering volatile liquid vapor and a method of reducing backpressure in a volatile liquid vapor recovery system or unit.

Abstract: Sample analysis in a portable analytical instrument, preferably in the form of a gas chromatograph, benefits from temperature control of one or more zones in the instrument by way of thermal energy developed from an energy reservoir. In a preferred embodiment, analytical instrument performs chromatographic analysis and the selected zone comprises a temperature-controlled thermal chamber, or oven (124) which includes a heating unit (118), a temperature sensor (128), and a cooling unit (130). A separation column column (118) is positioned within the oven (124). The energy reservoir comprises a first reservoir (125) of heating fluid in the form of a compressed light hydrocarbon, a second reservoir (126) of a compressed inert gas, or a combination thereof. A controlled temperature in the oven (124) resulting from the operation of the heating unit (118) and/or cooling unit (130) may be effected in response to a control signal generated by a computer (122).

Abstract: A pressure swing adsorption process for the recovery of oxygen from air improves upon a prior art process by depressurizing the adsorbent bed within an adsorbent vessel to an intermediate pressure by releasing void space gas from the product end of the vessel to a low purity oxygen tank while concurrently evacuating the adsorbent vessel from the feed end. This action enables an increased speed of depressurization and a reduction of the cycle time. Further, the adsorbent bed is repressurized to an intermediate pressure from the product outlet end with gas from the low purity oxygen tank, while concurrently pressurizing the adsorbent vessel from the input feed end. This action increases the load time fraction for a feed/vacuum blower. Further, oxygen is introduced to the product end of the adsorbent bed vessel from a high purity oxygen tank (which provides product to downstream applications) while concurrently, air is introduced to the feed end of the adsorbent bed within the vessel.

Abstract: An improved process for the oxygen enrichment of air by vacuum swing adsorption, pressure swing adsorption or a combination thereof, wherein the improvement comprises providing at least one packing at each of the air inlet to and air outlet from the adsorber, the packing at the air inlet side of the adsorber comprising Na-Ca zeolite X with an SiO.sub.2 /Al.sub.2 O.sub.3 ratio of 2.0 to 2.5 and with a CaO/Al.sub.2 O.sub.3 ratio of 0.4 to 0.75, the ratio being dependent upon the air inlet temperature, at an air inlet temperature of 20.degree. to 30.degree. C., the CaO/Al.sub.2 O.sub.3 ratio of the Na-Ca zeolite X at the inlet zone being 0.4 to 0.6, at an air inlet temperature of 30.degree. to 40.degree. C., the CaO/Al.sub.2 O.sub.3 ratio of the Ca zeolite X at the inlet zone being 0.55 to 0.65 and at an air inlet temperature of 40.degree. to 50.degree. C., the CaO/Al.sub.2 O.sub.3 ratio of the Na-Ca zeolite X at the inlet zone being 0.6 to 0.

Abstract: A vacuum swing adsorption process for separating a feed gas mixture into a more strongly adsorbable component and a less strongly adsorbable component in a process employing two vacuum pumps and three adsorbent beds containing an adsorbent selective for the more strongly adsorbable component using countercurrent depressurization and cocurrent ambient feed repressurization simultaneous with product end to product end pressure equalization and a common-shaft machinery arrangement which allows the expansion energy contained in the countercurrent depressurization and cocurrent ambient feed repressurization streams to be recovered and utilized to reduce overall process power consumption. Addition of three valves and an expander element will also allow expansion energy in the product purge and pressure equalization streams to be recovered. Oxygen product can be recovered from air at low cost using the process.

Abstract: Large vacuum pressure swing adsorption-oxygen plants are employed with four adsorption vessels, two air compressors, two vacuum pumps and an oxygen surge tank, operated on a (two) two-bed processing system basis. One two-bed system is offset from the other by one half of one half processing cycle. Reduced power and capital cost savings are achieved.

Abstract: A process for separating components of a gas by adsorption in an enclosure (1) divided into equal tight separated compartments (27) each provided with an adsorbent material (7, 8) chosen in function of the gas to be treated and each provided for temporarily allowing the gas to be treated to be introduced and at least one chosen component of the components of this gas to be evacuated whilst the other component or components of this gas are adsorbed by the material (7, 8), which process consists in introducing the gas to be treated into one of the compartments (27) until a predetermined pressure is reached while in the next compartments (27), gas to be treated is introduced in at least one compartment (27) and the chosen component is allowed to escape, the pressure in the next compartment (27) is allowed to drop so as to obtain a partial desorption of the non chosen component or components of the gas, a purging fluid is injected in the last compartment to achieve the final desorption, and device for carrying ou

Abstract: The disclosed hybrid membrane and pressure swing adsorption process can recover helium from source streams of about 0.5 to 5 percent by volume helium and concentrate the helium to a concentration of greater than about 98 percent by volume. The process comprises a membrane separation followed by two stages of pressure swing adsorption which are used in series. The source gas will primarily contain hydrocarbons but will contain some nitrogen. The membrane unit will contain a semipermeable membrane which is permeably selective for helium and will to the extent feasible reject hydrocarbons. The permeate gas will be increased in helium content by 2 to 10 times. Part of the residue gas is used in the regeneration of the adsorbent beds in the first stage of pressure swing adsorption. Each stage of pressure swing adsorption will contain a plurality of adsorbent beds, and will be cycled through multiple phases.

Abstract: A system is provided for recovering volatile-liquid vapor from an air-volatile liquid vapor mixture. The system includes a reaction vessel having a bed of adsorbent for adsorbing volatile liquid vapor and producing relatively volatile liquid vapor-free air. The system further includes a liquid seal vacuum pump for regenerating the adsorbent, a first conduit for circulating the air-volatile liquid vapor mixture through the system and a second conduit for circulating seal liquid to the vacuum pump. A cyclonic separator separates the seal liquid from the air-volatile liquid vapor mixture produced during bed regeneration. A mechanism is also provided for removing the volatile liquid vapor from the air-volatile liquid vapor mixture separated from the seal liquid. A method of recovering volatile liquid vapor from an air-volatile liquid vapor mixture is also disclosed.

Abstract: A process for separating a feed gas mixture into a more strongly adsorbable component and a less strongly adsorbable component in a plurality of adsorbent beds containing an adsorbent selective for the more strongly adsorbable component using cocurrent depressurization to provide purge gas and pressurization by product end to product end pressure equalization between beds simultaneous with cocurrent ambient and elevated pressure feed pressurization, and countercurrent evacuation. Oxygen product can be recovered from air at high recovery and adsorbent productivity levels using the process.

Abstract: Process swing adsorption processes for gas separation are carried out using overlapping pressure swing adsorption, feed gas repressurization and desorption steps. The adsorptive capacity of the system employed is increased, unit power consumption is decreased, and the overall efficiency of the operation is enhanced.

Abstract: The present invention is an apparatus and method for preferentially adsorbing carbon monoxide from a gas stream containing carbon monoxide in the presence of water and potentially ammonia while not adsorbing methane, hydrogen or carbon dioxide which may be present in the gas stream using an adsorbent of a supported cuprous compound situated downstream serially from a pretreatment adsorbent of 3A zeolite which protects the cuprous compound from water. An additional pretreatment layer of a basic metal compound to protect the acid-unstable 3A zeolite layer is also contemplated.

Abstract: A process claimed for the removal of VOCs from fluid streams. The process comprises a vacuum swing adsorption zone containing at least 2 adsorption beds wherein the adsorbent beds are cocurrently purged with a diluent stream comprising an inert gas prior to a countercurrent evacuation step. In addition, the adsorbent beds may contain a first adsorption layer comprising an adsorbent selective for the adsorption of the inert gas, whereby the inert gas is retained within the VSA system to prevent the creation of an explosive mixture upon the condensation of the desorbed VOCs.

Abstract: A process claimed for the removal of VOCs from fluid streams. The process comprises a vacuum swing adsorption zone containing at least 2 adsorption beds wherein the adsorbent beds are cocurrently purged with a diluent stream comprising an inert gas prior to a countercurrent evacuation step. In addition, the adsorbent beds may contain a first adsorption layer comprising an adsorbent selective for the adsorption of the inert gas, whereby the inert gas is retained within the VSA system to prevent the creation of an explosive mixture upon the recovery of the desorbed VOCs.

Abstract: Type X zeolites whose charge-compensating cations are composed of 95 to 50% lithium ions, 4 to 50% of one or more of aluminum, cerium, lanthanum and mixed lanthanides and 0 to 15% of other ions. The zeolites preferentially adsorb nitrogen from gas mixtures.

Abstract: The present invention provides a process for the recovery of methyl chloride from a mixture thereof with isobutane. The process employs pressure swing adsorption with a size selective adsorbent having a pore opening of between about 3.7.times.3.7 Angstroms and about 4.9.times.5.7 Angstroms, such as zeolite A, clinoptilolite and mixtures thereof to selectively adsorb methyl chloride from vent streams comprising methyl chloride and isobutane and recovering a tail gas stream enriched in methyl chloride. The process may be used in applications such as treating the vent gas streams from the direct synthesis of methyl chlorosilanes. The process provides an economical route to recovering a valuable raw material in the process of making silicones and reduces the volume and methyl chloride content of the vent stream which is typically incinerated to avoid the release of halogenated hydrocarbons to the atmosphere.

Abstract: A process for separating a feed gas mixture into a more strongly adsorbable component and a less strongly adsorbable component in a plurality of adsorbent beds containing an adsorbent selective for the more strongly adsorbable component using pressurization by product end to product end pressure equalization between beds simultaneous with cocurrent ambient and elevated pressure feed pressurization, coproduction of product and purge gas, and cocurrent depressurization for pressure equalization gas simultaneous with countercurrent evacuation. Oxygen product can be recovered from air at high recovery using the process.

Abstract: A process claimed for the removal of VOCs from fluid streams. The process comprises a vacuum swing adsorption zone containing at least 2 adsorption beds wherein the adsorbent beds are cocurrently purged with at diluent stream comprising an inert gas prior to a countercurrent evacuation step. In addition, the adsorbent beds may contain a first adsorption layer comprising an adsorbent selective for the adsorption of the inert gas, whereby the inert gas is retained within the VSA system to prevent the creation of an explosive mixture upon the condensation of the desorbed VOCs.

Abstract: Vacuum and other pressure swing adsorption vessels are monitored, and corrective adjustments are made in the pressure equalization and/or repressurization steps in response to imbalances in the temperature profiles of the vessels in order to tune the system. The PSA process is also desirably purge tuned to avoid over purging or under purging of each vessel.

Abstract: The present invention is a process for recovering hydrogen from dilute refinery off gases using a vacuum swing adsorption process having a simultaneous cocurrent depressurization to provide purge gas for another bed under the influence of a vacuum and countercurrent depressurization to vent void space gas and/or adsorbed gas to ambient.

Abstract: The selective adsorption of nitrogen from air is used in a system including a number of adsorbers, to give oxygen enriched gas at elevated pressure, the adsorber is regenerated by depressurization under atmospheric pressure with a pump and by repressurization with oxygen enriched gas. The pumping duration is at most equal to the duration of the production step.