Abstract: The present invention is a process for adsorbing carbon dioxide from a carbon dioxide containing gas mixture comprising contacting the gas mixture with an activated carbon adsorbent having a density in the range of approximately 0.56 to 0.61 g/cc (35 to 38 lbs./ft.sup.3) and adsorbing the carbon dioxide on the activated carbon adsorbent.

Abstract: A high purity isobutane adsorption separation and purification apparatus is provided including a pressure regulator which regulates the pressure of an isobutane-containing gas; the at least one adsorption bed packed with zeolite 5A and carbon molecular sieve arranged downstream of and operatively associated with the pressure regulator; a flow control valve disposed between the pressure regulator and the at least one adsorption bed; a surge tank operatively associated with and for receiving a purified isobutane product from the at least one adsorption bed; a vacuum pump operatively associated with and for removal of impurities from the at least one adsorption bed; and valves disposed between the pressure regulator and the at least one adsorption bed, between the at least one adsorption bed and the surge tank, and between the at least one adsorption bed and the vacuum pump. An adsorptive separation and isobutane purification process is also provided which may be used with the apparatus of the invention.

Abstract: In a process for separating a gas mixture in a pressure swing adsorption device comprising an adsorber, two outlet vessels and a rotary machine at the inlet, the rotation of the rotary machine is reversed during the first depressurization step (c-d) then during the first repressurization step (g-h), so that these first steps are each broken down into two sub-steps in which the inlet for the adsorber successively experiences two opposite flows, whereas the outlet of the adsorber experiences a flow, respectively leaving or entering, of constant direction. The process is particularly useful in the production of oxygen from air.

Abstract: A vacuum pressure swing adsorbent (VPSA) system and method for separating a component from a fluid mixture and including a fluid source for introducing the mixture into the system and a supply apparatus for collecting the separated component. A pair of adsorbent bed vessels is interposed between the fluid source and the supply apparatus to adsorb and desorb a predetermined component under respective adsorption and desorption pressures characterized by a low pressure ratio and relatively high desorption pressure values. Implementation of a single-stage vacuum device made possible by the use of the high desorption pressure, results in further reduction in both equipment and operating costs.

Abstract: A PSA process involving the storage of products of various purities in segregated storage tanks for subsequent usage is disclosed. Products of increasing purities, admitted at the product end of the bed, are used during purging and repressurization steps. In addition, different composition streams collected at the feed end of the bed during the countercurrent depressurization step are admitted at the feed end of the bed, in the order of increasing product component content, during the rising pressure step(s). This cycle gives higher recovery and lower bed size factor than prior art PSA cycles.

Abstract: High purity carbon monoxide is separated from a gas stream containing carbon monoxide, carbon dioxide, methane, hydrogen and possibly other impurities by a two-stage pressure swing adsorption process carried out in a series of adsorption vessels containing adsorbent which adsorbs carbon monoxide more readily than other components of the gas stream. The first adsorption vessel in the series is cocurrently purged with nonadsorbed product stream from the second vessel and the purge effluent from the first stage adsorption vessels is reintroduced into the first adsorption vessels as feed gas.

Abstract: A process for producing hydrogen gas by reacting steam with a gas mixture containing carbon monoxide, carbon dioxide and hydrogen to produce a hydrogen-enriched product gas and subjecting the product gas to pressure swing adsorption to produce a high purity hydrogen product and a hydrogen-depleted waste gas is improved by drying, where necessary, part of the gas mixture and subjecting the dry gas mixture to pressure swing adsorption using a carbon monoxide-selective adsorbent to produce a high purity carbon monoxide product gas and a carbon monoxide-depleted waste gas. Where the gas mixture is produced by endothermic reaction, one or both of the hydrogen-depleted waste gas and the carbon monoxide-depleted waste gas can be used as fuel to supply heat for the endothermic reaction.

Abstract: This process comprises at least one stage of first decompression/first recompression by balancing the pressures between two adsorbers (2A to 2D) as well as the taking off of a constant product gas rate during the adsorption phase. In the course of the first decompression, the product gas taken off is passed to an auxiliary capacity (6) which is arranged in parallel to the product line (1) and can be connected to the product outlet side of each adsorber (2A to 2D). During the second recompression stage, the adsorber receives the product gas taken off in countercurrent and is at the same time put into communication with the auxiliary capacity. The process is useful in the production of hydrogen from a constant rate of a feed gas mixture.

Abstract: The apparatus for the separation of a gas mixture by pressure swing adsorption (PSA) comprises at least one adsorber A and a first vessel T which can be selectively connected to the adsorber in order temporarily to store the gas which is extracted from the adsorber and reintroduced into it during a cycle, the vessel T having a fixed free internal volume V, a vertical main direction of height h, with the relationship 25.ltoreq.h.sup.3 /V.ltoreq.150, and the gas fraction entering and leaving the vessel T at its lower part, and remaining therein for a time which does not exceed 300 seconds. The apparatus is useful in the production of oxygen or hydrogen.

Abstract: A process for the treatment of a gaseous mixture by adsorption with variable pressure, in an adsorption installation comprising at least one adsorber. For each adsorber, there is a succession of steps defining an adsorption phase, a regeneration phase for the adsorbent comprising a depressurization step, and a pressure increase phase. The passage from one phase to the following comprises switching of at least one valve between open and closed positions. At least one valve switching is carried out according to a programmed progressive slope to control a first cocurrent decompression stage of the adsorber with transfer of gas toward a lower pressure portion of the installation. The transferred gas is sent, for at least partially balancing pressure, to another adsorber in a pressure increase phase.

Abstract: An improved oxygen generator (20) includes an air compressor (21) having a pressure port (22) and a suction port (23) and being selectively operable to produce a flow of air from the suction port to the pressure port; a molecular sieve (30) having an inlet communicating with the compressor and having an outlet, the sieve being adapted to adsorb nitrogen from a flow of gas passing therethrough; a storage tank (33) communicating with the sieve outlet and adapted to store oxygen-rich gas passing through the sieve; and a control valve (24) operatively arranged between the compressor and the sieve and being selectively movable between a first position in which air flows from the compressor suction port through the sieve to the storage tank and a second position in which oxygen-rich gas flows from the storage tank through the sieve and control valve to desorb nitrogen in the sieve.

Abstract: A process for removing nitrogen oxides, as well as water and carbon dioxide, from gas streams containing at least 0.2 ppm by volume of nitrogen oxides by passing the gas stream through an alumina adsorbent and a zeolite adsorbent, preferably 13X-zeolite. The process has utility in front end cleanup of air prior to cryogenic distillation of the air where nitrogen oxides would otherwise freeze under the cryogenic processing.

Abstract: A pressure swing adsorption process for absorbing CO.sub.2 from a gaseous mixture containing CO.sub.2 comprising introducing the gaseous mixture at a first pressure into a reactor containing a modified alumina adsorbent maintained at a temperature ranging from 100.degree. C. and 500.degree. C. to adsorb CO.sub.2 to provide a CO.sub.2 laden alumina adsorbent and a CO.sub.2 depleted gaseous mixture and contacting the CO.sub.2 laden adsorbent with a weakly adsorbing purge fluid at a second pressure which is lower than the first pressure to desorb CO.sub.2 from the CO.sub.2 laden alumina adsorbent. The modified alumina adsorbent which is formed by depositing a solution having a pH of 3.0 or more onto alumina and heating the alumina to a temperature ranging from 100.degree. C. and 600.degree. C., is not degraded by high concentrations of water under process operating conditions.

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 rotary valve system which includes of a pair of valve assemblies each of which has valve parts with flat faces which, when pressed together and rotated, provide valving action between various ports incorporated in one valve part of each assembly. The first valve part of each assembly contains a circular array of through openings, each of which is connected to a conduit. The second valve part of each assembly contains several passages which provide communication between various openings of the first valve part and valve apertures located in the second valve part of each assembly. The second valve part of each assembly also contains one or more passages which provide communication between members of one or the other array of openings. The valve system can be effectively used to automate operation of a gas or liquid adsorption system comprising two or more adsorption vessels, the number of vessels being equivalent to the total number of openings in either array.

Abstract: A single-bed PSA system comprising a blower, an adsorber vessel, and a gas product storage tank separates a gas mixture using a three-step cycle comprising adsorption, evacuation, and pressurization. Pressurization is accomplished by introducing gas from the gas product storage tank into both the feed end and the product end of the adsorber vessel. Preferably a portion of the pressurization gas is introduced into the adsorber vessel by the blower, which also is used for providing feed to the adsorber and for withdrawing gas from the adsorber during the evacuation step.

Abstract: A pressure swing adsorption apparatus to vary selectively the concentration of at least one constituent of a gaseous mixture by sending a gaseous mixture into an adsorber to generate a particular product gas while delivering to another adsorber both a predetermined portion of the product gas to purge the other adsorber of its adsorbed gas and a selected amount of the product gas, independent of the flow rate and in addition to the predetermined portion, to produce a desired relative concentration of the constituents of the product gas from a range of relative concentrations.

Abstract: Four adsorbers 1 to 4, each operating in a cycle comprising (described for adsorber 2): an adsorption step 1 wherein a feed from adsorber 2 is circulated to adsorber 2; an adsorption step 2 wherein feed is injected to the bottom of adsorber 2 and a product rich in isoparaffins is recovered from the head of adsorber 2; an adsorption step 3 wherein a portion of the fluid leaving adsorber 2 is sent to adsorber 3; an adsorption step 4 wherein the head of adsorber 2 receiving the feed is connected to the bottom of adsorber 3; a first depressurisation step 5 wherein adsorber 2 at high pressure is connected to adsorber 4 at a lower pressure; a second depressurisation step 6 wherein the head of adsorber 2 is closed; a stripping step 7 wherein the bottom of adsorber 2, which receives desorbent overhead, is connected to the top of adsorber 2; two principal stripping steps 8 and 9 wherein adsorber 2 alone is supplied with desorbent; a stripping finishing step 10 wherein adsorber 2 is continued to be supplied with desorb

Abstract: A method of controlling an oxygen concentrator having a first sieve bed operated over successive control periods according to a duty cycle for alternately pressurizing and flushing the first sieve bed and a second sieve bed operated over the successive control periods according to a reciprocal of the duty cycle is disclosed. The duty cycle and the reciprocal duty cycle are adjusted during every second one of the successive control periods to change the pressurizing relative to the flushing of the first sieve bed and to change the flushing relative to the pressurizing of the second sieve bed, for reducing concentration of oxygen produced. The duty cycle and the reciprocal duty cycle are adjusted during remaining control periods to change the flushing relative to the pressurizing of the first sieve bed and to change the pressurizing relative to the flushing of the second sieve bed, such that water vapor is purged from the first and second sieve beds after pressurizing thereof.

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 disclosed for the production of a high octane product from a feed mixture comprising C.sub.5 -C.sub.6 normal paraffins in which an equilibrium reaction to produce mono and dimethyl branched paraffins is achieved by conducting the reaction and the product separation in a pressure swing adsorption and reaction zone containing a uniformly distributed adsorbent for the selective adsorption of normal paraffins and a catalyst for the equilibrium conversion of normal paraffins to mono and dimethyl branched paraffins. More specifically, the process achieves the isomerization of the normal paraffins by the reaction of the normal paraffins in the presence of hydrogen with the simultaneous removal of the mono and dimethyl branched paraffin product at the same temperature and pressure. In one embodiment, the passing of the feed mixture to the bed is terminated and the bed is purged with one of the reactants which in turn further reacts to displace heavier paraffin and enhance the overall product octane.

Abstract: Process for treating a gas mixture by pressure swing adsorption wherein for each adsorber (1), the duration (T.sub.R) of the countercurrent recompression step is much less than that (T.sub.D) of the cocurrent decompression step. The process is particularly useful in the production of oxygen from atmospheric air.

Abstract: The invention relates to an apparatus and method for controlling the pressure in a fuel tank ullage. The apparatus includes a vapor pump which withdraws vapors from the tank ullage responsive to a signal generated by a pressure sensor in communication with the ullage. The vapors are directed to a canister containing a VOC-adsorbent material where the VOC content of the vapor is removed. Non-polluting VOC-free air is vented from the canister to the atmosphere. The invention also contemplates the provision of a second canister which would accept the tank ullage vapors after the material in a first canister becomes saturated. A portion of the VOC-free air exiting the first canister is used a purge gas to regenerate the saturated material in the first canister. The operation of the multiple canisters would alternate between adsorption and regeneration until the tank ullage pressure is reduced to below a threshold level.

Abstract: A method for increasing product recovery or reducing the size of steam methane reformer and pressure swing adsorption systems utilized for hydrogen production. A significant portion of the hydrogen in the PSA depressurization and purge effluent gas, which is otherwise burned as fuel in the reformer, is recovered and recycled to the PSA system to provide additional high purity hydrogen product. This is accomplished by processing selected portions of the depressurization and purge effluent gas in adsorbent membrane separators to increase hydrogen content for recycle to the PSA system. Remaining portions of the depressurization and purge effluent gas which contain lower concentrations of hydrogen are utilized for fuel value in the reformer.

Abstract: A process for pressure swing adsorption of oxygen from a gas mixture containing at least oxygen and nitrogen to recover an unadsorbed nitrogen enriched product from a plurality of parallel piped adsorbent beds undergoing adsorption, depressurization and repressurization wherein the improvement is conducting a pressure transfer from one bed to another from an intermediate point of the bed finishing adsorption to a point closer to the feed end of a bed that is repressurizing to improve productivity and recovery of nitrogen enriched gas in the process.

Abstract: The flow rate of a nonadsorbed product gas stream from a multiple unit PSA plant can be reduced in response to a reduced product demand by isolating all units in the plant and inserting an idle step into the adsorption cycle immediately following bed equalization steps of the cycle. In a preferred embodiment, the duration of the idle step is inversely proportional to the percentage reduction in the product demand. To maintain the product gas purity at the desired level, minor adjustments of the idle step duration can be made following adjustment to the idle step in response to a change in product demand.

Abstract: A process for separating a mixture of gases by selective adsorption, in which pressure swing is used to induce both desorption and the flow of gas through at least one simulated moving chromatographic column.

Abstract: Pressure swing apparatus comprises at least three parallel beds of adsorbent operated on cycles of being on-line to adsorb contaminant from a feed gas stream under pressure, being depressurized, being regenerated by a purge gas, and being repressurised. Feed gas is transferred from a depres-surising bed to a repressurizing bed to reduce switch loss and repressurization is extended to occupy at least 50% of the cycle to smooth the feed gas output.

Abstract: An air separation method in which a pre-purification unit is provided with three or more beds which are subjected to a pressure swing adsorption process. Each of the beds is subjected to feed, pressurization, purge and repressurization stages. The purge stages are conducted with a waste stream from the air separation unit and the duration of the purge stage is equal to the total time of the cycle divided by the number of beds.

Abstract: A contaminated air purifying apparatus capable of decreasing particles such as dust floating in air, soot produced by a combustion engine and the like and air pollutants such as nitrogen oxides (NOx) contained in exhaust gas. Particulates such as dust, soot and the like are electrostatically negatively charged and collected in a purifying filter section by coulombic force. NOx is converted into N.sub.2 and CO.sub.2 by an action of carbon fiber or carbon particles, resulting in decreased in concentration. The carbon fiber and carbon particles are preferably modified into an increased surface area of 200 to 2000 m.sup.2 /g.

Abstract: During a purge step of a PSA plant the waste gas being vented is analyzed to identify when a preselected volume of the waste gas contains purge gas after which the purge step is stopped.

Abstract: A continuous pressure driven adsorption process for separating a multi-component gaseous mixture. In accordance with the method, the multi-component gaseous mixture is passed through a first portion of the adsorbent to adsorb one or more preferentially adsorbed components while a second portion of the adsorbent is regenerated. The multi-component mixture is passed through the first portion of the adsorbent in sections and the second portion of the adsorbent is regenerated in sections. The sections forming the first portion of the adsorbent become successively less saturated and the sections forming the second portion of the adsorbent becomes successively more concentrated in the more preferentially adsorbed component. A product stream is expelled from the less saturated section of the first portion of the adsorbent. The product stream is enriched in the less preferentially adsorbed component(s).

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: An oxygen selective adsorbent and a method for making an oxygen selective adsorbent wherein a porous carbon substrate such as a carbon molecular sieve, activated carbon, carbon black, coal, or petroleum coke, is impregnated with a solution of an acidic species and the impregnated substrate is dried. The oxygen selective adsorbent can be used in a pressure swing adsorption process for the separation of oxygen from nitrogen, for example, in air.

Abstract: A device (10) for removing contaminants from truck air systems or the like includes an assembly including a desiccant canister (100), a carrier (46), and a bottom closure (28) vertically removable in a passage (14) of a collar (12) mounted to the truck. The carrier (46) includes a horizontal plate (48) which divides the passage (14) into a coalescing chamber having a horizontally orientated, tubular coalescing filter (98) extending vertically above and diametrically over the sump including an electrically actuated purge valve (42) of the bottom closure (28). Air is directed vertically downward from the filter (98) by vertical legs (62) extending down from the horizontal plate (48) and on opposite sides of the filter (98). A follower plate (118) is biased in the canister (100) against the desiccant beads (116) by a wave spring (140) sandwiched thereagainst by a slideable retainer (142) fixed in the side wall (104) of the canister (100).

Abstract: A two stage pressure swing adsorption process is set forth for producing the less strongly adsorbed component of a feed gas mixture wherein the first stage utilizes a first adsorbent for bulk removal of the more strongly adsorbed component and wherein the second stage utilizes a second adsorbent for trace removal of the more strongly adsorbed component. A further feature of the present invention is that the desorbed gas from the second stage's depressurization step (consisting primarily of the desired less strongly adsorbed component) is recycled to the first stage in order to improve its performance. In a preferred embodiment of the present invention, high purity nitrogen (less than 1000 ppm oxygen, preferably less than 100 ppm oxygen) is produced from an air feed using a kinetically controlled carbon molecular sieve adsorbent in the first stage and an equilibrium controlled metal complex-based adsorbent in the second stage.

Abstract: A stocker for accommodating, storing or transporting articles in clean, contamination-free conditions for either a long time or temporarily. The stocker has a particle collector provided in a part thereof. The particle collector includes an irradiation source such as ultraviolet light source, and a photoelectron emitting material that emits photoelectrons on irradiation with irradiation energy from the irradiation source. The particle collector further includes an electric field forming electrode, and a charged particle collecting material. The space where the particle collector is provided is preferably partitioned from the other space of the stocker by an irradiation energy screening material.

Abstract: A pressure swing adsorption plant for the separation of gas mixtures includes at least one pressure vessel containing an adsorbent bed that is able preferentially to adsorb at least one component of the gas mixture. The pressure vessel has an inlet at its top for the feed gas mixture, an outlet at its bottom for non-adsorbed gas and at least one heat conductive member containing a liquid medium arranged within the bed such that, in operation, heat is able to be conducted by convection through the liquid from a region of maximum temperature at or near the bottom of the bed to a region of minimum temperature at or near the top of the bed.

Abstract: Improved apparatus for fractionating fluid mixtures by pressure swing molecular adsorption employing a rotary distributor valve and an array of adsorber columns. The columns are, in one embodiment, contained within a product holding tank or, in another embodiment, attached to a product tank. The valve sequences to provide a quasi steady-state flow, allowing optimization of adsorption/desorption cycles, and eliminating most of the valves, switches and plumbing usually required.

Abstract: A process for obtaining highly-purified gas by selectively separating at least one gaseous impurity from a gaseous mixture by the known pressure swing adsorption method uses a holding column of the feed-in/feed-out sequence retaining type and at least three adsorption columns containing adsorbents. Each adsorption column is pressurized and depressurized in cycle to repeat adsorption and desorption steps. During this, the holding column is used as an intermediate gas reservoir to improve the efficiency of the separation. In this invention, the capacity of the holding column is insufficient to hold the whole amount of purge gas.

Abstract: A process is provided for removing sulfur oxides from gaseous mixtures such as flue gases or tail gases. The process involves contacting the gaseous mixture with a non-functionalized polymeric sorbent which is essentially hydrophobic, such as styrenic polymers. The process may utilize pressure swing adsorption techniques, and is capable of producing a desorption stream with an SO.sub.2 concentration suitable for immediate conversion to elemental sulfur by the Claus process.

Abstract: In the process for the production of oxygen by adsorption, the following combination of steps are used: the number of adsorbers is at least three; the time of pumping y under sub-atmospheric pressure during step b) is higher than dephasing T/n, and at least equal to the time x of the production step; the phase of pumping of the column of adsorbent material is carried out by using on said adsorption column successively at least two systems of pumping wherein one is in operation from the start of the pumping operation, another one is adapted to operate until pumping is over.

Abstract: A process for separation of a gas mixture containing three components, e.g. a mixture comprising hydrogen, carbon monoxide and carbon dioxide produced by steam reforming a hydrocarbon, by pressure swing adsorption is disclosed.

Abstract: An improved apparatus for fractionating fluid mixtures by pressure swing molecular adsorption employing a rotary distributor valve and an array of adsorber columns. The columns are contained within a product holding tank. The valve sequences to provide a quasi steady-state flow, allowing optimization of adsorption/desorption cycles, and eliminating most of the valves, switches and plumbing usually required.