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: An apparatus and method for supplying oxygen to passengers on board an aircraft in the form of a portable machine including a housing having a shape and size allowing it to be positioned under a seat on the aircraft, an air separation device in the housing for separating oxygen from the air inside the aircraft, a self-contained compressed air supply in the housing including a compressor operatively connected to the air separation device and a brushless d-c motor for driving the compressor, and a circuit for connecting the d-c motor to the aircraft electrical power source including converting the a-c voltage and current on board the aircraft to d-c voltage and current for operating the motor. The brushless motor insures compliance with airline requirements that the machine generates a low level of electrical interference. The machine includes an intake resonator and a muffler associated therewith for reducing the level of noise generated to a value acceptable for airline use.

Abstract: Oxygen of uniform purity is produced in a two-bed air-fed oxygen pressure swing adsorption process in which the beds are operated out of phase. The steps of the adsorption cycle include a pressurization/production step and a bed regeneration step, with the bed undergoing regeneration being purged with a low pressure stream of the oxygen-enriched gas produced as the nonadsorbed product of the process. The oxygen concentration in the purged gas effluent is continuously periodically monitored, and the maximum oxygen concentration in the effluent during selected purge steps is compared with the maximum oxygen concentration in the effluent during a previous purge step, and the difference is used to adjust the timing and duration of a purge step following the selected purge step in a manner that reduces the difference between the oxygen concentration in the sequential purge steps.

Abstract: A process for treating a gaseous mixture, particularly air, by pressure swing adsorption (PSA), of the type in which three adsorbers (1 to 3) are used in each of which is carried out, for a given nominal production, a cycle comprising the following successive stages, the cycle being offset from one adsorber to the other by a third of the nominal duration (T) of the cycle:(a) a substantially isobaric adsorption phase at a high pressure (PM) of the cycle, by circulation of the mixture through the adsorber in a so-called co-current direction;(b) a desorption phase comprising a stage (b2) of pumping to a low pressure (P.sub.m) of the cycle less than atmospheric pressure, via a vacuum pump (7) of constant speed and continuous operation whose output is in the vicinity of atmospheric pressure; and(c) a repressurization phase of the adsorber to the high pressure of the cycle. During a reduction of the production flow rate, the mean intake pressure of the vacuum pump is raised for the duration of the cycle.

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: In a pressure-swing adsorption-type gas separation unit, a distinct intermediate gas passageway is formed between a first water retaining bed (A) and a second separating adsorbent bed (B), a controlled heat flow being supplied to prevent the formation of a very cold area between both beds. The unit is particularly useful in the production of oxygen from air.

Abstract: The components of a gas mixture are separated by pressure swing adsorption in a plurality of adsorption vessels. In the first step of the half-cycle adsorption takes place in a first bed while the second bed undergoes countercurrent desorption. At the end of the first step the first bed is vented countercurrently and the first and second beds undergo, as a first bed equalization step, outlet-to-outlet equalization or outlet to both inlet and outlet equalization. The vent step may precede or be concurrent with the first bed equalization step. In a second equalization step the beds simultaneously undergo inlet-to-inlet and outlet-to-outlet equalization. The second bed is then further pressurized with nonadsorbed product gas. The half cycle is then repeated but with the first bed being substituted for the second bed and vice versa.

Abstract: A pressure swing adsorption process employs a simultaneous equalization and evacuation step followed by simultaneous feed and product gas repressurization steps, resulting in faster processing, and a reduction in power requirements, in the recovery of oxygen and argon from feed air.

Abstract: A method and apparatus suitable for sweetening sewerage which avoids the need for pumping the sewerage. The method comprises the steps of passing the sewerage under a gas-tight enclosure and causing it to fall as a stream through a first passageway, passing bubbles of a gas, such as oxygen, up through the descending sewerage to dissolve in the liquid stream to form a gas-liquid stream and causing the gas-liquid stream to ascend through a second passageway in which further bubbles of the gas are passed therethrough to dissolve further gas in the stream to balance the liquid density in the descending and ascending streams.

Abstract: A method of treating a material with ozone including the steps of passing oxygen rich gas from a PSA plant 2 through an ozonizer 4 and then passing the ozonized oxygen thus formed directly back to the PSA plant where the ozone is adsorbed in a bed of silica gel contained within a vessel. During the desorption step nitrogen adsorbed in a bed of zeolite also located in the vessel desorbs the ozone from the bed of silica gel and a nitrogen-ozone gas leaves the PSA plant via a line in the feed end. The material is treated with the nitrogen-ozone gas.

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: 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 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: A pressure swing adsorption apparatus including a compressor for pumping a flow of a gaseous mixture through an adsorption medium utilizes a capacity control system by which the operating capacity of the compressor can be preselected. The capacity control system is disposed upstream, i.e. on the suction side of, the compressor for limiting, when desired, the feed stream drawn into the compressor. A reduction in the operating capacity of the apparatus by way of the control system results in a corresponding reduction in the power consumption and noise levels of the compressor.

Abstract: A process for removing argon from a feed gas stream comprising oxygen and argon to yield a high purity oxygen stream and the system for carrying out the process. The process includes the steps of: (a) providing a feed gas of oxygen and argon at a temperature between -30.degree. C. and 100.degree. C. and a pressure between 5 psia and 160 psia; and (b) passing the feed gas over an adsorbent bed comprising a Ag ion exchanged type X zeolite wherein at least 80% of the available ion sites are occupied by Ag such that at least a portion of the argon in the feed gas is adsorbed by the adsorbent bed thereby leaving an oxygen-enriched gas stream.

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: In using calcium-exchanged forms of zeolite X as selective adsorbents for nitrogen in PSA air separation process, it has been discovered that, particularly under certain temperature and pressure conditions, the peak performance is not, as is generally believed, obtained when the calcium content is at a maximum, but rather when the degree of calcium exchange is in the range of 60 to 89 equivalent percent and only when the framework Si/Al.sub.2 ratio of the zeolite is within the range of 2.0 to 2.4.

Abstract: Waste heat generated within a pressure swing adsorption system is effectively captured and utilized to preheat the feed gas passing to a feed gas blower for compression to the desired adsorption pressure level. The energy efficiency of the system, and overall system performance, are thereby enhanced.

Abstract: A system for controlling the atmosphere of a container for use in the storage and/or transportation of perishable goods which includes adsorption apparatus for the selective adsorption in whole or in part and in a predeterminded order of any water vapor, carbon dioxide, oxygen or ethylene contained within the atmosphere, a blower for urging the atmosphere to the adsorption apparatus, and a conduiting for returning the controlled atmosphere to the container.

Abstract: Pressure swing adsorption air and other gas separation operations are carried out using specific preferred zeolite adsorbent compositions based on the symmetry of the framework atoms and cations therein. Specific SiO.sub.2 /Al.sub.2 O.sub.3 and cation/cation ratios for enhanced performance are identified. LiX adsorbent having a silica to alumina ratio on the order of 2.364 provides enhanced PSA performance.

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 trans-atmospheric pressure swing adsorption process is carried out using product gas for purge and partial repressurization in the production of oxygen from air. No transfer of gas is made directly from one bed to another, as for pressure equalization purposes, but the power requirements are reduced under controlled pressure swing conditions.

Abstract: Lithium/alkaline earth metal X zeolites in which the lithium:alkaline earth metal equivalent ratio is from about 95:5 to about 50:50 and lithium/alkaline earth metal A zeolites in which the lithium:alkaline earth metal equivalent ratio is from about 10:90 to about 70:30 are useful for separating oxygen and nitrogen from mixtures because they combine high adsorption capacity with high thermal stability.

Abstract: A method for separating gases wherein the gases to be separated are contacted with a particulate composite material with a carbon matrix to selectively adsorb gases. The material contains a microporous phase which is essentially carbon with a microporous volume between 0.1 cm.sup.2 /g and 1 cm.sup.2 /g, which is associated with an amorphous mineral dispersed phase containing an oxide of silicon, aluminum, titanium or magnesium disposed on the carbon phase at a thickness of less than 10 nm.

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 with two cocurrent depressurizations, first to provide product and then to provide a purge gas, and using a combination of less strongly adsorbable component and feed gas mixture to repressurize the adsorbent bed. Oxygen product can be recovered from air at high recovery using the process.

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 process is conducted in a circuit having first and second adsorbers and a product reservoir vessel, connected serially. The feedstock is a gas mixture containing contaminant and product components (for example, air containing N.sub.2 and O.sub.2). The process steps involved are: (1) feeding a charge of feed gas into the first adsorber, temporarily retaining it therein, and pressurizing it, so that the adsorbent adsorbs most of the contaminant component and purified product gas is produced; (2) co-currently depressurizing the first adsorber by discharging purified product gas through the second adsorber and reservoir vessel; (3) counter-currently venting both adsorbers; (4) partly re-pressurizing both the adsorbers with purified gas from the reservoir vessel; and then repeating steps (1)-(4) inclusive.

Abstract: A two stage pressure swing adsorption process is set forth for producing high purity oxygen from a feed air stream wherein carbon dioxide, water and preferably nitrogen are removed in the first stage and wherein an oxygen selective adsorbent is used to adsorb oxygen in the second stage. The oxygen product is recovered upon depressurization of the second stage. The high purity of the oxygen product is achieved by rinsing the oxygen selective adsorbent with oxygen prior to the depressurization step. A key to the present invention is that the effluent streams from the second stage feed and rinse steps are used to regenerate the first stage adsorbent(s) in a specific regeneration scheme.

Abstract: In a unit for the production of oxygen by separation of air by adsorption with regeneration of the adsorbers (1-5) under vacuum, the sub-atmospheric depressurization is ensured with rejection to the atmosphere by pumping with two successive pumping devices: one, for example of the type of a volumetric compressor (13), operates to a pressure of the order of 0.5.times.10.sup.5 Pa absolute, while the other, for example of the type of a centrifugal compressor (14), operates alone to a pressure of the order of 0.2.times.10.sup.5 Pa absolute.

Abstract: A single bed, air separation PSA system utilizes an external product surge tank to supply product oxygen and purge gas to the adsorbent bed. An equalization tank supplies void space gas to the bed for repressurization purposes.

Abstract: A pressure swing adsorber system includes a pneumatically driven booster compressor to increase the pressure of the output product gas. A pair of inlet valves controls feed air flow to the sieve beds and the drive cylinder of the booster compressor and are cycled so that one valve opens to pressurize one sieve bed before the other valve closes to allow the other sieve bed vent to atmosphere. During the time that both valves are open, the pressure in the two sieve beds and on opposite sides of the drive cylinder equalize and a portion of the gas in the pressurized sieve bed and drive cylinder side is captured rather than being vented to ambient. System efficiency is increased by selecting whether captured gas from the last pressurized sieve bed or drive cylinder side reaches the next to be pressurized sieve bed first.

Abstract: A pressure swing adsorption process is set forth for the recovery of two gas products at high recovery and high purity using the steps of adsorption, depressurization, low pressure purge, evacuation and repressurization. The purge effluent and a portion of the depressurization effluent are used to partially accomplish the repressurization step.

Abstract: The present invention is directed to a process for separating nitrogen from gas mixtures containing nitrogen and less strongly adsorbed components such as oxygen, hydrogen, argon or helium at ambient temperatures or above by use of a magnesium exchanged, sodium A-zeolite in a preferred level of magnesium exchange and an appropriate pressure range for adsorption and desorption of bulk gases which provides improved recovery and reduced bed size factor.

Abstract: An operating system for dual-sieve oxygen concentrators, as used by invalids, provides a method and apparatus for controlling the purging and release of product gas and the cycling period in response to the pressure build-up in each sieve column. The cycling period is thereby self-adjusting to changes in the capacity of the columns. Restricting flow of product gas and purge gas to the higher-pressure part of the adsorption period provides product gas of higher purity and reduces the loss of oxygen in the purge.

Abstract: A method and an apparatus for separating a specific component gas from a mixed gas, wherein granular adsorbent is held in a sealed space in a layered state, easily adsorptive gas is adsorbed to the granular adsorbent by blowing material mixed gas into the adsorbent layers and contacting the granular adsorbent with a counter-current of material gas, and the granular adsorbent is transferred gradually out of the sealed space, and reactivated by desorbing the easily adsorptive gas from the granular adsorbent, and the reactivated granular adsorbent is returned to the inside of the sealed space to be reused. Therefore, frequent actions of opening and closing valves are unnecessary, so that it is possible to separate and produce excellent product gas with high purity.

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 pressure equalization between beds after initial depressurization to provide a purge gas, using countercurrent evacuation wherein at least two adsorption beds are countercurrently evacuated simultaneously in overlapping countercurrent evacuation steps in the plurality of adsorption beds, and using a combination of less strongly adsorbable component and feed gas mixture to repressurize the adsorbent bed. Oxygen product can be recovered from air at high recovery using the process.

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 pressure equalization between beds after initial depressurization to provide a purge gas and using a combination of less strongly adsorbable component and feed gas mixture to repressurize the adsorbent bed. Oxygen product can be recovered from air at high recovery using the process.

Abstract: The present invention provides a process for utilizing one stream from a gas separation unit in an evaporation cooler to provide cool water which is used to cool the feed gas mixture by direct or indirect contact prior to entering the gas separation unit.

Abstract: The present invention concerns a polyphase particulate composite material containing a microporous phase which is essentially carbon whose microporous volume is between 0.1 cm.sup.3 /g and 1 cm.sup.3 /g, which is associated with an amorphous mineral dispersed phase essentially consisting of an oxide of silicon, aluminum, titanium or magnesium disposed on the carbon phase, at a thickness of less than 10 nm. The invention is also concerned with a process for the preparation of these composite materials, and the use thereof as a molecular sieve.

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: 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: Low silica X (LSX) zeolites having a framework Si/Al ratio equal to 1.0 with lithium exchange levels greater than a threshold level of 70% exhibit unexpectedly higher capacity for nitrogen adsorption compared to LSX-zeolite with lower lithium exchange levels. These materials provide high performance adsorbents for PSA air separation processes at a lower cost for the adsorbent because of the lower threshold lithium exchange levels compared to highly exchanged lithium X-zeolite known in the prior art.

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: The invention is a process for selectively adsorbing nitrogen from a gas mixture which comprises contacting the gas mixture with an adsorbent that has a moderate nitrogen capacity and a high selectivity for nitrogen over the other components in the mixture. With respect to air separation, improved adsorbents have low O.sub.2 capacity with N.sub.2 capacity at roughly the same level as current adsorbents such as CaA. O.sub.2 VSA computer process simulations have shown the unexpected result that for materials with the same binary isothermal working selectivity, those with lower isothermal nitrogen working capacity are superior O.sub.2 VSA adsorbents, provided that they have a nitrogen working capacity of at least about 0.3 mmol/g.

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.

Abstract: The present invention is directed to adsorptive separation of nitrogen with active adsorbent phases with high N.sub.2 capacity and high heats of adsorption when diluted with inert material at levels ranging from 5% to 80%. The presence of diluent reduces the temperature swings in the adsorbent bed, which increases the utilizable effective N.sub.2 working capacity and decreases the relative amount of O.sub.2 left unrecovered on the active adsorbent phase. The net result is equal or better process performance allowing utilization of a lower amount of active adsorbent phase. Use of a diluent having a higher heat capacity than that of the active adsorbent phase increases these benefits, but dilution effects are beneficial even for diluents with heat capacities equal to or lower than that of the active adsorbent phase.

Abstract: The present invention is directed to a process for separating nitrogen from gas mixtures containing nitrogen and less strongly adsorbed components such as oxygen, hydrogen, argon or helium by use of an at least binary exchanged X-zeolite having lithium and a divalent cation selected from the group consisting of barium, cobalt, copper, chromium, iron, magnesium, manganese, nickel, zinc and mixtures thereof in a ratio of preferably 5% to 50% of the divalent cation and 50% to 95% lithium.

Abstract: A pressure swing adsorption process is set forth for the recovery of two gas products at high recovery and high purity using the steps of adsorption, depressurization, evacuation and repressurization. A portion of the depressurization effuent is used to partially accomplish the repressurization step.

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.