Abstract: A process for separating a feed gas stream containing elemental oxygen and nitrogen to produce a purified nitrogen gas stream by removing oxygen from the feed gas stream using an ion transport membrane to produce a retentate gas stream and a permeate gas stream, wherein the feed gas stream or the retentate gas stream is purified to remove impurities either before or after the separation step to produce the purified nitrogen gas stream.

Abstract: Bulk separation of carbon dioxide from methane is accomplished using a modified pressure swing adsorption system where the adsorbent used is a naturally occurring sodium-rich clinoptilolite. Most of the carbon dioxide can be removed at low operating pressures, and the principal agent of regeneration is a high volume air rinse rather than pressure reduction.

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: An air prepurification process which includes, as a first step, a pressure swing adsorption process in which the air is passed through a bed of adsorbent which contains activated alumina, thereby effecting removal of substantially all moisture and most carbon dioxide from the feed air and as a second step, a temperature swing adsorption process in which the dried feed air is passed through a bed of carbon dioxide-selective adsorbent, thereby removing substantially all of the carbon dioxide remaining in the feed air. The feed air may be passed through beds of hydrogen oxidation and carbon monoxide oxidation catalysts between the first and second steps to convert any hydrogen and carbon monoxide in the feed air to water vapor and carbon dioxide, respectively, these components being removed from the feed air during the second step.

Abstract: Process for the separation of the hydrogen contained in a gas mixture contaminated by carbon monoxide and containing at least one other impurity chosen from the group consisting of carbon dioxide and saturated or unsaturated, linear, branched or cyclic C.sub.1 -C.sub.8 hydrocarbons, comprising bringing the gas mixture to be purified into contact, in an adsorption region, with at least:one first adsorbent selective at least for carbon dioxide and for C.sub.1 -C. hydrocarbons andone second adsorbent which is a zeolite of faujasite type exchanged to at least 80% with lithium, the Si/Al ratio of which is less than 1.5, in order to remove at least carbon monoxide (CO).

Abstract: An air prepurification process carried out in a battery of three adsorption vessels arranged in parallel. The process includes three steps: a first step in which non-steady state PSA is carried out in the first and second vessels operated in alternating adsorption and bed regeneration mode while the adsorbent in the third vessel undergoes thermal regeneration; a second step in which non-steady state PSA is carried out in the second and third vessels operated in alternating adsorption and bed regeneration modes while the adsorbent in the first vessel undergoes thermal regeneration; and a third step in which non-steady state PSA is carried out in the first and third vessels operated in alternating adsorption and bed regeneration modes while the adsorbent in the second vessel undergoes thermal regeneration.

Abstract: The invention is a pressure swing adsorption system. The pressure swing adsorption system has a plurality of primary adsorbent beds and at least one secondary adsorbent bed. The feed gas stream is flowed to a primary adsorbent bed loaded with an adsorbent that will preferentially adsorb certain components in the feed gas. Non-preferentially adsorbed components flow from the adsorbent bed during this time. Upon saturation of the adsorbent with the adsorbed components, the flow of feed gas is ceased. The adsorbent is fully loaded with the preferentially adsorbed component and there is feed gas in the void space between the adsorbent particles. This primary adsorbent bed undergoes regeneration by partial depressurization through the secondary adsorbent bed followed by a complete depressurization to a final lower pressure. There can be two or more primary adsorbent beds and there will be at least one secondary adsorbent bed.

Abstract: A process and apparatus for drying and removing carbon dioxide from a hydrogen and carbon monoxide containing synthesis gas by using adsorption vessels containing a first layer of 13 X-zeolite and a second layer of 3 A-zeolite in which the 3 A-zeolite precludes the formation of water of reaction when dry and carbon dioxide-free synthesis gas is used to regenerate the adsorption vessel countercurrent to feed flow of the synthesis gas.

Abstract: The invention provides a regenerable supported amine sorbent having an amine concentration of from about 35 wt. % to about 75 wt. %. The balance of the sorbent is a porous support which provides the sorbent with structural rigidity and a surface for gas/solid contact. The invention further provides a process for making the sorbent and system for cyclically absorbing and desorbing carbon dioxide using a plurality of sorbent beds.

Abstract: In the purification of air to remove water and carbon dioxide and other contaminants prior to cryogenic separation of oxygen and nitrogen, water and carbon dioxide are adsorbed on a solid adsorbent and are periodically desorbed to regenerate the adsorbent by the passing of a heated regenerating gas such that the quantity of heat added to the regenerating gas to produce desorption is no more than 90 percent of the heat of adsorption liberated during the adsorption of the water and carbon dioxide. The process is applicable to removing other contaminants from other gas streams also.

Abstract: Temperature swing adsorption to remove CO.sub.2 from a gas stream is conducted using alumina to adsorb all the water and at least most of the carbon dioxide from the gas stream. Optionally a downstream zone of zeolite may be provided to remove further carbon dioxide and hydrocarbons.

Abstract: A process is set forth for the selective removal of water, CO.sub.2, ethane and C.sub.3 + hydrocarbons from gas streams, particularly a natural gas stream comprising primarily methane. The process comprises contacting the gas stream with an adsorbent material consisting exclusively of one or more compounds which are basic (i.e. compounds which, when contacted with a pH neutral aqueous solution, cause such solution to have a pH greater than 7.0) and which are mesoporous (i.e. compounds which have moderately small pores providing a surface area less than 500 m.sup.2 /g). The key to the present invention is the use of a single homogenous adsorbent without sacrificing performance. Typical mesoporous adsorbents which are useful in the present invention include zinc oxide, magnesium oxide and, in particular, activated alumina.

Abstract: A method and apparatus are disclosed showing a system for continuous purification of bulk source specialty gases to less than 10 part per billion levels. Corrosive and non-corrosive specialty gases are purified using this system. Depending on whether corrosive or non-corrosive gases are being purified and the contaminants of concern, the purification beds contain an absorber and/or getter. A dual bed system allows one bed to purify at ambient temperatures while a second bed undergoes regeneration, providing continuous purification for a bulk source specialty gas.

Abstract: An adsorption process and system for the selective adsorption of a more readily adsorbable component, such as nitrogen, as from air or other feed gas mixture is carried out using a composite adsorbent bed containing different adsorbent materials positioned in separate zones in which the temperature conditions favor adsorption performance of the particular adsorbent material under applicable processing conditions in each zone. A method for the selection of the adsorbent materials is based on Adsorption Figure of Merit values.

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 process for the adsorption of at least carbon dioxide, water and oxides of nitrogen and preferably acetylene from a feed gas, comprises contacting the feed gas with an adsorbent mixture of a zeolite and an alumina. The process may be operated as a swing adsorption process comprising contacting the gas with the adsorbent at a first temperature and pressure to adsorb at least carbon dioxide, water and oxides of nitrogen therefrom and periodically regenerating the adsorbent by reducing the pressure and or increasing the temperature to which the adsorbent is exposed.

Abstract: The invention comprises a PSA gas prepurifier for the removal of contaminants present in a feed gas stream. The prepurifier of the invention has a bed of adsorbent material which comprises at least two discrete layers of adsorbents, at least one of the adsorbents being comparatively strong and at least another of the adsorbents being comparatively weak.

Abstract: Multiple thermal pulses are employed to regenerate segments of an adsorber bed simultaneously in thermal swing adsorption processes. The invention is particularly applicable to air purification as it helps to reduce purge flow and improve regeneration efficiency.

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 method and system for separating one or more components from gas mixtures uses a moving bed of adsorption material particles under continuous and substantially isobaric pressure conditions. Contaminated gases are likewise purified by removing one or more contaminants therefrom using such a moving bed of adsorption material particles under continuous and substantially isobaric pressure conditions.

Abstract: An air prepurification system which includes vertically oriented adsorption vessels containing, from top to bottom, a layer of moisture-selective adsorbent, a first layer of carbon dioxide-selective adsorbent and a second layer of carbon dioxide-selective adsorbent wherein the particle size of carbon dioxide-selective adsorbent in the second layer of carbon dioxide-selective adsorbent is smaller than the particle size of both the moisture-selective adsorbent and the carbon dioxide-selective adsorbent in the first layer of carbon dioxide-selective adsorbent. The air purification system is designed for use in a temperature swing adsorption process in which air is passed downwardly through the adsorption vessels during the adsorption step and upwardly through the vessels during the adsorbent regeneration step.

Abstract: An apparatus is disclosed for removal of contaminate(s) from a gas stream in an oil or gas refinery using an absorber-regenerator process wherein a portion of the contaminate rich overhead gas from the regenerator is utilized to increase the partial pressure of the contaminate at the absorber so as to enhance selective absorption of the contaminate(s).

Abstract: A pressure swing process for air separation to produce concentrated gaseous oxygen at an elevated pressure without the requirement of further compression of the gaseous oxygen product. The process comprises the steps of compressing the feed air to a pressure in the range of approximately 45 psig to 105 psig, preheating the feed air to each of the adsorption beds to a temperature in the range of approximately 100.degree. F. to 200.degree. F., then directing flow of the feed air cyclically into and through at least two crystalline zeolite molecular sieve adsorption beds for selectively adsorbing at least nitrogen therein. In this manner, oxygen having a purity of approximately 88% to 93% at a recovery of approximately 30% to 45% and a bed size factor in the range of 2,500 pounds to 4,000 pounds of adsorbent per ton per day of oxygen can be delivered to a receptor tank at an elevated pressure of approximately 40 psig to 100 psig.

Abstract: An adsorption process and system for the selective adsorption of a more readily adsorbable component, such as nitrogen, as from air or other feed gas mixture is carried out using a composite adsorbent bed containing different adsorbent materials positioned in separate zones in which the temperature conditions favor adsorption performance of the particular adsorbent material under applicable processing conditions in each zone. A method for the selection of the adsorbent materials is based on Adsorption Figure of Merit values.

Abstract: A method and apparatus for the purification and collection of hydrogen isotopes in a flowing inert gaseous mixture containing impurities, wherein metal alloy getters having the capability of sorbing non-hydrogen impurities such as oxygen, carbon dioxide, carbon monoxide, methane, ammonia, nitrogen and water vapor are utilized to purify the gaseous mixture of impurities. After purification hydrogen isotopes may be more efficiently collected. A plurality of parallel process lines utilizing metal getter alloys can be used to provide for the continuous purification and collection of the hydrogen isotopes.

Abstract: A process for the production of hydrogen that purifies a synthesis gas stream, containing hydrogen, carbon monoxide and combustibles, in a PSA unit. The PSA unit produces at least three streams: a substantially pure hydrogen product stream, a combustible-rich first tail-gas stream, and a carbon dioxide-rich second tail gas stream.

Abstract: Selective separation and recovery of gaseous components of hot waste gas of combustion containing carbon dioxide is attained by causing the hot waste gas to contact an adsorbent containing as a substantial main component thereof an inorganic solid substance exhibiting surface basicity and inducing adsorption of the gaseous components of the hot waste gas on the adsorbent and then selectively separating the adsorbed gaseous components by virtue of differences in retention time among the gaseous components on the adsorbent.

Abstract: A mixed gas consisting of carbon dioxide and nitrogen is separated into the component gases by a method which comprises treating sepiolite with nitric acid, subjecting the treated sepiolite to an ion-exchange treatment thereby exchanging the cationic metal present in the treated sepiolite with Mg ions, heating the sepiolite resulting from the ion-exchange treatment, and exposing the ultimately prepared sepiolite to the mixed gas.

Abstract: A system for adsorbing a plurality of contaminants from a workstream composed of a first stage open-ended activated carbon monolith adsorber, a second stage open ended activated carbon monolith adsorber downstream of the first stage. The first stage activated carbon has an average pore size that is larger than the average pore size of the second stage activated carbon.

Abstract: Pressure swing adsorption to remove CO.sub.2 from a gas stream is conducted using an improved alumina obtained by impregnating a starting alumina with a basic solution having a pH of at least 9, e.g. of a basic compound such as KHCO.sub.3, and drying at a temperature low enough to avoid decomposing the basic compound to a form which adsorbs CO.sub.2 such that the compound does not regenerate under reduced pressure purging.

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: 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: Separation of nitrogen and carbon dioxide is accomplished by a method using as a separating material one member selected from the group consisting of sepiolite in the unmodified form, sepiolite which has been heat-treated, and sepiolite which has had part or the whole of the exchangeable cation thereof replaced with zinc ion and which has been subsequently subjected to a heat treatment.

Abstract: The present invention relates to the separation of one or more components from a multi-component gaseous stream. The component(s) being separated are relatively small molecular diameter gas components. They are separated by sorption techniques wherein the sorbent is a unique class of layered nanostructure materials, such as carbon nanofibers, characterized as having; (i) a surface area from about 0.2 to 3,000 m.sup.2 /g as determined by N.sub.2 adsorption at -196.degree. C., (ii) a crystallinity from about 5% to about 100%, and (iii) interstices from about 0.335 nm to about 0.67 nm.

Abstract: In a pressure swing adsorption plant for the production of oxygen enriched gas a pressure vessel contains a first bed of molecular sieve adsorbent located adjacent an outlet 4 of the vessel which has an optimum operating efficiency at approximately ambient temperature and a second bed 10 of molecular sieve adsorbent which has an optimum efficiency below that of ambient operating temperature located adjacent the inlet 2.

Abstract: A method for the removal from a feed gas stream such as air of at least two contaminating gas components such as water and CO.sub.2 features repeated cycles of operation the improvement which comprise: feeding a regenerating gas such as dry nitrogen at a higher temperature, e.g. 70.degree. C., in a direction counter-current to the feed direction in contact with the adsorbent to produce a heat pulse travelling in the counter-current direction to desorb the less strongly adsorbed second contaminating gas component from the downstream (with respect to the feed direction) portion of the adsorbent by TSA while at the same time desorbing the more strongly adsorbed second contaminating gas component from the upstream (with respect to the feed direction) portion of the adsorbent by PSA.

Abstract: A process and system for removing contaminants from air comprises flowing a compressed air stream comprising water and carbon dioxide to a first adsorbent zone for contacting with a first adsorbent effective in the adsorption of water by flowing the air in a direction within the first adsorbent zone parallel with the axis of the first adsorbent zone to form a dry gas; flowing the dry gas from the first vessel to a second adsorbent zone comprising a second adsorbent disposed in a radial arrangement about the same axis to remove carbon dioxide. Regeneration of the adsorbent beds may be carried out independently.

Abstract: Carbon dioxide is removed from a gas stream by passing the gas stream through a bed of natural or synthetic clinoptilolite or their chemically-modified derivatives. The process is particularly advantageous when applied to the removal of ppm levels of carbon dioxide from gas streams at temperatures above 20.degree. C.

Abstract: An adsorption process in which high and low pressure feed streams are introduced into a plurality of beds to produce product streams by adsorbing one or more preferentially adsorbed components within the beds. Each bed is subjected to a low pressure feed stage to produce a low pressure product stream followed by a high or higher pressure feeding stages to produce one or more high pressure product streams. Thereafter the beds are regenerated through depressurization and purge stages. The cycle is conducted out of phase so that one of the beds is producing the high pressure product stream while another bed is producing a low pressure product stream.

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: Carbon dioxide is removed from gas streams comprised predominantly of gases that are less polar than carbon dioxide by passing the gas stream through a bed of type X zeolite having a silicon to aluminum atomic ratio not greater than about 1.15, thereby adsorbing the carbon dioxide from the gas stream. The process is particularly advantageous when applied to the removal of low levels of carbon dioxide from gas streams at temperatures above 20.degree. C.

Abstract: In an aircraft, a pressure swing adsorption system (23) is used both for removing carbon dioxide and water vapour from recycled cabin air and for producing in an emergency oxygen from pressurized engine bleed air.

Abstract: The present invention is an apparatus and process for separating oxygen from air by adsorption of at least nitrogen on multiple layers of air separation adsorbent in an adsorption bed wherein the multiple layers are Na X-zeolite followed by at least another layer of adsorbent selected from the group consisting of Ca X-zeolite, Li X-zeolite, Ca A-zeolite followed by Ca X-zeolite, Ca A-zeolite followed by Li X-zeolite, Ca X-zeolite followed by Li X-zeolite, Li X-zeolite followed by Ca X-zeolite and Mg A-zeolite followed by Ca X-zeolite.

Abstract: A process for removing carbon dioxide regeneratively from a hot gas stream, containing flue gases or fuel gases, wherein the gas stream is successively: a) used for heating (1) and/or desorbing (2) a solid absorbent loaded with carbon dioxide; b) optionally used for generating energy (12); c) passed through an absorber (3) in which carbon dioxide from the gas stream is absorbed on the absorbent, and: d) is discharged (11); and wherein: e) the absorbent from step c) is desorbed in ta desorber (2) at least partially and optionally under elevated pressure and is then returned to step c). A system for carrying out the process is also described. The process and the system are suitable for removing carbon dioxide from combustion gases and for shifting (coal) gasification gases toward hydrogen.

Abstract: A process for restarting an adsorption receptacle which is part of an installation for the purification of hydrogen by pressure swing adsorption (PSA), which receptacle, during a hiatus in its operation, has been depressurized and then rendered inert with nitrogen. The receptacle is repressurized with practically pure hydrogen, and then the adsorption cycle is restarted in this receptacle. The repressurization is effected counter-current with respect to the adsorption direction in the receptacle. The receptacle is repressurized with hydrogen produced by the installation before the hiatus. The process can be used for the treatment of a catalytic hydrocarbon reforming gas, in which case the receptacle contains successively, in the adsorption direction, a layer of alumina, a layer of carbon and a layer of molecular sieve.

Abstract: There is diclosed a process for purifying hydrogen gas which comprises removing impurities such as nitrogen, oxygen, methane, carbon monoxide, carbon dioxide and moisture contained in a crude hydrogen gas by bringing the crude hydrogen gas into contact under heating with a hydride of a zirconium alloy such as Zr-V, Zr-V-Ni, Zr-V-Cr, Zr-V-Co, Zr-V-Fe, Zr-V-Cu, Zr-V-Ni-Cr, Zr-V-Ni-Co and Zr-V-Cr-Fe. By virtue of using the above Zr alloy hydride, the process enables highly advanced purification of crude hydrogen gas by removing such impurities as above to a level as low as 1 ppb or less in high safety and efficiency at low installation and running costs.

Abstract: A method and apparatus are provided for use in the delivery of an inhalation anesthetic to a patient while employing a closed loop or re-breather gas recirculation system. The method and apparatus control the system temperature to minimize heat buildup, including heat buildup resulting from an exothermic reaction between a patient's exhaled breath and a scrubbing substance that removes a selected constituent from the patient's exhaled breath. The apparatus includes an enclosure containing a scrubbing substance. The enclosure defines an influent opening for admitting the exhaled breath along a first path into the scrubbing substance and defines an effluent opening through which gases can be discharged from the enclosure. The apparatus also includes a second path adjacent the first path between inlet and outlet openings whereby a coolant fluid can flow along the second path to remove heat from the interior of the enclosure.

Abstract: The present invention discloses an improved method of producing a low-cost, nitrogen-based inert atmosphere suitable for radiation curing of resins, coatings, etc. from non-cryogenically generated nitrogen. According to the disclosed method, residual oxygen present in non-cryogenically generated nitrogen is converted to either moisture or a mixture of moisture and carbon dioxide by reaction with a reducing gas in a catalytic reactor prior to using the nitrogen-based atmosphere for radiation curing of moisture insensitive materials such as resins and coatings.