Abstract: A VOC removal or destruction system incorporates a regenerator/reactivator having a cylindrical ceramic tube for receiving contaminated adsorbent activated carbon. Electrodes are provided in the ceramic tube in contact with the activated carbon and a programmable logic controller is connected to control the voltage applied to the electrodes and the current flowing through the activated carbon within the tube. The temperature of the material in the tube is controlled by the programmable controller to maintain a temperature within one of two temperature ranges for regenerating the activated carbon and for reactivating the activated carbon. An inert gas is supplied through the tube in contact with the contaminated adsorbent material; the effluent gas including the stripped VOC's is supplied to an oxidizer for destruction. The oxidizer includes a stoichiometric burner providing combustion products for oxidizing the gaseous adsorbate and for providing carrier gas to the regenerator/reactivator.

Abstract: An adsorption/desorption unit includes a hollow enclosure containing one or more elongate hollow elements of activated carbon fiber cloth (ACFC) of appropriate length to cross sectional area to provide suitable electrical resistance for heating. The elements conduct electrical current to heat to a temperature that permits selective adsorption of a gas stream constituent and subsequent desorption to recover sorbate. An enclosure houses the ACFC elements and is arranged to direct gas stream flow through the elements and into and out of the enclosure via gas ports. The ability to heat the elements to a desired temperature by electrical current flow allows for straightforward implementation of selective adsorption. After an adsorption step, altering the temperature of the element or elements enables desorption.

Abstract: A method for the decontamination of fluid (liquid or supercritical) carbon dioxide fluid, especially of hydrocarbon contaminants, down to ≦100 ppb concentration are described. The critical component is a high silica zeolite, preferably a high silica Y-type zeolite, ZSM-5 or a high silica mordenite, which in a variety of physical forms is capable of decontaminating such fluid CO2 to ≦100 ppb, ≦10-50 ppb, or ˜1 ppb, without being detrimentally affected by the supercritical operating environment. The high silica zeolite may be produced by the removal of alumina from a natural or synthetic zeolite while retaining the desirable zeolite structure, to a silica:alumina ratio of from 20-2000:1. Preferably the zeolite is disposed in separate quantities in at least two vessels, which operate alternately. A portion of the purified product from the operating vessel is directed to the other vessel and there used to remove accumulated contaminants from that vessel's zeolite.

Abstract: The present invention provides for a multi-composite adsorbent mixture which will remove H2O, CO2 and nitrogen oxides and/or hydrocarbons from a feed gas stream. The improvement lies in the use of a third adsorbent which is selective for nitrogen oxides, hydrocarbons or both.

Abstract: A method for storing natural gas by adsorption which comprises separating an available natural gas in an infrastructure side (10) into a low carbon number component mainly containing methane and ethane and a high carbon number component mainly containing propane, butane and the like, and storing the low carbon number component by adsorption in a first adsorption tank (16) and storing the high carbon number component by adsorption in a second adsorption tank (18). The method can solve the problem that the high carbon number component condenses within a pore of an adsorbing agent and hence the adsorption of the carbon number component, the main component of natural gas, is inhibited, and thus improves the storage density. Accordingly, the method can be used for ensuring a high storage density also for an available natural gas. An adsorbing agent for use in the method is also disclosed.

Abstract: This invention is directed to a method and system for purifying hexafluoroethane near its critical temperature and pressure, particularly where the hexafluoroethane contains at least about 1 ppb by weight of a non-volatile residue. A combination of a sand trap, an adsorption assembly made of a glass wool-molecular sieve-glass wool combination, and a filter is used.

Abstract: A gas adsorption separation process characterized by adsorption separation of components in a gas by contacting the gas with a porous solid which is a porous solid having an X-ray diffraction pattern with at least one peak at a diffraction angle corresponding to a d value of 1 nm or greater; and having a nitrogen adsorption isotherm measured at liquid nitrogen temperature with at least one section where the change in nitrogen adsorption in terms of the volume of nitrogen under standard conditions is 50 ml/g or greater with a relative vapor pressure change of 0.1 in a relative vapor pressure range of 0.2-0.8; wherein the porous solid possesses mesopores with a median pore size of 2-50 nm in the pore size distribution curve and pore walls that are porous.

Abstract: A method and apparatus for preventing contamination of a substrate or a substrate surface, and particularly relates to prevention of contamination of raw materials, semi-finished products, base materials of products and substrate surface in a high-tech industry such as in the production of semiconductors and liquid crystals. A gas coming into contact with a base material or substrate is purified by dust removing apparatus and adsorption and/or absorption apparatus so that the concentration of fine particles in the gas is below class 1,000 and a non-methane hydrocarbon concentration is below 0.2 ppm. Thereafter, the base material or the substrate surface is exposed to this gas.

Abstract: This invention provides a pressure swing adsorption process for purifying a synthesis gas stream containing from 60 to 90 mole % hydrogen and impurities such as CO2, CH4, N2, and CO. The PSA process of the invention further provides a method of adsorbing substantially all of the nitrogen and other contaminants from the feed gas stream; wherein the feed stream is passed at superatmospheric pressure through a plurality of adsorbent beds and each adsorbent bed contains at least a CaX, LiA, LiX or calcium containing mixed cation zeolite having a SiO2/Al2O3 mole ratio of 2.0-2.5. Such process involves sequentially pressurizing, depressurizing, purging and repressurizing the adsorbent beds with product hydrogen, and recovering product hydrogen in purities of 99.9% or greater from the beds.

Abstract: Adsorbents useful in the selective adsorption of unsaturated hydrocarbons, the manufacture of the adsorbents, and processes for the separation of unsaturated hydrocarbons using the adsorbents.

Abstract: A synthesis gas obtained by steam reforming is sent to a pressure swing adsorption unit (2) which separates a CO/H2 mixture, as a production gas, from the other constituents. The CO/H2 mixture is sent to a unit (3) for at least partially purifying CO, for example a permeation unit, which produces under pressure the CO with high purity or an H2/CO mixture with an adjusted CO content, containing very little impurities.

Abstract: A pressure swing adsorption process for the separation of hydrogen from a mixture of the same with methane, utilizing two separate PSA stages, one containing a nitrogen selective crystalline zeolite, and the second containing a methane selective adsorbent.

Abstract: The present invention provides a method and apparatus to purify various gases utilizing the superior performance a heated getter process in a smaller package than previous multiple stage, heated getter processes. The smaller package includes inner and outer enclosures, and an integral, regenerative heat exchanger to simultaneously increase heater efficiency and cool the purified gas. The invention also includes a particle filter to remove particles from the gas flow. The invention further provides an interface to various modular gas stick substrate designs with an inlet and an outlet in one end of the integrated heated getter purifier system. The inlet gas is preheated by the integral heat exchanger and then heated to operating temperature of 200-400° C. The heated getter removes various impurities from the gas. The heated gas is then cooled in the integral heat exchanger. The cooled gas is exposed to a second quantity of cooler getter to remove residual impurities.

Abstract: A system for cleaning the air, such as air in the interior of motor vehicles, airplanes, buildings or shelters, having organic substances such as alcohols, alkanes and aliphatic and aromatic hydrocarbons. The air cleaning system includes a cylindrical adsorber. The cylindrical adsorber has a plurality of circular segments for passing air to be cleaned and for passing desorption air through the adsorber. The adsorber contains adsorption agents, such as a hydrophobic zeolite, that can be regenerated with microwaves. The air cleaning system also includes a microwave unit disposed on adsorber and an oxidation catalyst.

Abstract: A rotary concentrator heats media in a desorption zone to a desorption temperature, then removes the pollutants using a second cold desorbent gas stream in a desorbent zone. First, the adsorbent media is rotated and an inlet gas stream is passed over the media in the adsorbent zone, thereby removing the adsorbable pollutants. A first gas stream having a temperature equal to or greater than the desorption temperature of the adsorbable pollutants is passed over the media in the desorbent zone to heat the media to generally the desorption temperature of the adsorbable pollutants. A second gas having a temperature less than the desorption temperature of the adsorbent media is passed over the media in the desorbent zone to remove the adsorbable pollutants from the desorbent zone. Subsequently, the gas containing the adsorbable pollutants received from the desorbent zone is processed by destroying or removing the adsorbable pollutants.

Abstract: A method and plant to process a fluid comprising one or more compounds G2 having a kinetic diameter less than or equal to that of nitrogen and one or more compounds G1 having a kinetic diameter greater than or equal to that of methane. The method and plant use in combination, several adsorption and desorption stages during which a first stream F1 mainly comprising compounds G1, a second stream F2 enriched in compounds G2, a third stream F3 mainly comprising compounds G2 and a fourth stream F4 mainly comprising compounds G1 are produced. At least a fraction of stream F3 is used to flush adsorption section A1.

Abstract: A process is provided for the removal of trace amounts of aromatic hydrocarbons from an acid waste gas feed stream comprising sulfur compounds and the aromatic hydrocarbons. An adsorption process employing an adsorbent such as a high silica zeolite adsorbent having a framework silica-to-alumina ratio greater than about 15 and having a pore size greater than about 6.2 angstroms is used to remove from the feed gas mixture aromatic hydrocarbon contaminants and permit the recovery of a high purity sulfur product from the treated effluent stream. The use of the present invention removes aromatic hydrocarbon contaminants which are responsible for the degeneration of the performance of the downstream sulfur recovery zone.

Abstract: Channel flow filtration media possessing high efficiency and low pressure drop is formed from a plurality of filtration layers at least some of which include a multi-dimensional channel pattern having a plurality of continuous, tortuous channels and a multi-dimensional edge at each end of the plurality of channels formed therein. The filtration medium is configured as a stack with the multi-dimensional edge of the channel pattern forming a plurality of inlets open through a first face of the stack, a plurality of outlets open through a second face of the stack, and a corresponding plurality of disruptive fluid pathways passing from the inlets through the stack to the outlets. The filtration layers may be formed from a non-woven material, such as a carbon loaded multi-layer BMF web capable of adsorption of undesired vapors and odors from a fluid.

Abstract: A process, particularly of the TSA type, for separating impurities of the nitrogen protoxide (N2O) and possibly carbon dioxide (CO2) or ethylene (C2H4) type which are contained in a gas stream, such as air. The impurities of nitrogen protoxide type are removed on a faujasite zeolite having a Si/Al ratio of 1 to 1.5 and containing from 0 to 35% of K+ cations, between 1 and 99% of Na+ cations and between 1 and 99% of Ca2+ cations, preferably at least 50% of Ca2+ cations. The separation is preferably carried out at a temperature of approximately −40° C. to +80° C., preferably at room temperature. Advantageously, the process is employed for prepurifying atmospheric air before cryogenic distillation of the air thus prepurified.

Abstract: The present invention is a portable filter fan. A highly efficient and inexpensive air filtering device is made from a portable box fan with a pleated sheet o micron particle filter installed externally in channels on the inlet side of the fan housing. Activated charcoal used for removing odors and volatile organic compounds from the air is prevented from egress by a second similar filter mounted externally in channels on the outlet side of the fan housing. A low-cost fan filter sitting at floor level circulates the air and cleans the air more efficiently than many other filters placed in ceiling or attic areas. Gravity pulls the floating particles in the air downward toward the floor, and the new portable air filtering box fan draws and holds the particles on the filter.

Abstract: Process for recovering a solvent from a gas coming from a treating process using the solvent, the gas having a low temperature Ta and a high temperature Td, the difference Td-Ta being sufficient to carry out an adsorption step and a desorption step. The process is characterized in that/ a) a first solvent-containing gas stream is sent to an adsorption step, this gas being at a temperature Ta, at the end of this step the gas is practically solvent-free and the solvent is collected in a first adsorber, b) a second gas stream at a temperature Td, this gas being solvent-free, is sent to carry out desorption of a second adsorption means loaded with solvent during a previous step a), and c) the solvent is sent at least partly to a step of the treating process using the solvent.

Abstract: The present invention relates to a process for preparing mono-disperse adsorber resin gels by polymerizing monomer droplets to give monodisperse polymers, followed by haloalkylating and crosslinking the resultant polymers, and also relates to the use of these resins.

Abstract: A filter assembly includes a shaped adsorbent article disposed in a housing. The shaped adsorbent article has one or more projections extending from a surface of the article toward the housing to provide for flow of fluid between the shaped adsorbent article and the housing. The filter assembly may optionally includes a diffusion channel for additional filtering and/or one or more porous polymer films disposed over inlet or outlet openings in the housing to reduce or prevent particulate contamination. The filter assembly may be used in a device, such as a computer disk drive, to filter a fluid, such as air, within and/or entering or exiting the device.

Abstract: According to the present invention, a process is provided which overcomes historical limitations to the capacity of PSA units for a wide variety of gas separations. Capacities in excess of about 110 thousand normal cubic meters per hour (100 million standard cubic feet per day) can now be achieved in a single integrated process train. The corresponding significant equipment reduction results from a departure from the accepted principle in the PSA arts that the length of the purge step must be equal to or less than the length of the adsorption step.

Abstract: A pressure swing adsorption process for the separation of hydrogen from a mixture of the same with methane, utilizing two separate PSA stages, one containing a nitrogen selective crystalline zeolite, and the second containing a methane selective adsorbent.

Abstract: An adsorptive monolith made by extruding a mixture of activated carbon, a ceramic forming material, a flux material, and water, drying the extruded monolith, and firing the dried monolith at a temperature and for a time period sufficient to react the ceramic material together and form a ceramic matrix. The extrudable mixture may also comprise a wet binder. The monolith has a shape with at least one passage therethrough and desirably has a plurality of passages therethrough to form a honeycomb. The monolith may be dried by vacuum drying, freeze drying, or control humidity drying. The monolith is useful for removing volatile organic compounds and other chemical agents such as ozone from fluid streams. Particularly useful applications include adsorptive filters for removing ozone from xerographic devices and other appropriate office machines and volatile organic compounds from automobile engine air intake systems.

Abstract: A process for purifying halosilanes consisting of contacting a mixture comprising a halosilane and a hydrocarbon with silica gel, thereby reducing the hydrocarbon content of the mixture. The present process is particularly useful for removing hydrocarbon contaminates from chlorosilanes, where the hydrocarbon contaminates have a boiling point similar to that of the chlorosilanes.

Abstract: A filter assembly includes a shaped adsorbent article disposed in a housing. The shaped adsorbent article has one or more projections extending from a surface of the article toward the housing to provide for flow of fluid between the shaped adsorbent article and the housing. The filter assembly may optionally include a diffiusion channel for additional filtering and/or one or more porous polymer films disposed over inlet or outlet openings in the housing to reduce or prevent particulate contamination. The filter assembly may be used in a device, such as a computer disk drive, to filter a fluid, such as air, within and/or entering or exiting the device.

Abstract: A method for generating electric power, such as at, or close to, natural gas fields. The method includes conditioning natural gas containing C.sub.3+ hydrocarbons and/or acid gas by means of a membrane separation step. This step creates a leaner, sweeter, drier gas, which is then used as combustion fuel to run a turbine, which is in turn used for power generation.

Abstract: Device and method for removing volatile compounds from a gas stream, the device including a material which is capable of removing and retaining the volatile compounds while displaying a visible color change, wherein at least some moisture has been removed from the material and there is relative movement between the gas stream and the material.

Abstract: A filter assembly includes a shaped adsorbent article disposed in a housing. The shaped adsorbent article has one or more projections extending from a surface of the article toward the housing to provide for flow of fluid between the shaped adsorbent article and the housing. The filter assembly may optionally include a diffusion channel for additional filtering and/or one or more porous polymer films disposed over inlet or outlet openings in the housing to reduce or prevent particulate contamination. The filter assembly may be used in a device, such as a computer disk drive, to filter a fluid, such as air, within and/or entering or exiting the device.

Abstract: Adsorbent composites composed of microparticulate zeolites at least 90% of whose particles have a characteristic particle dimension not greater than about 0.6 micron and a macropore inert binder. The composites are useful for separating strongly adsorbed gas components from gas mixtures. Microparticulate type X zeolites composites are particularly useful for separating nitrogen or carbon dioxide from air.

Abstract: A low energy cost process for the co-production of oxygen and nitrogen employing a fuel tube extending into the first oxygen selective ion transport membrane whereby fuel is introduced adjacent to the closed end and flows cocurrently with oxygen containing gas in the annulus and an oxygen selective ion transport membrane having a separator section and a reactor section. An oxygen-containing feedstock, typically air, is compressed and then contacts the cathode side of the separator section where a portion of the oxygen contained within the feedstock is transported to the anode side of the separator section and recovered as an oxygen product gas. Substantially the remainder of the oxygen contained within the feedstock is transported from the cathode side of the reactor section to the anode side and exothermically reacted with a fuel. Following the exothermic reaction, hot nitrogen rich product gas is expanded in a turbine to generate the power necessary to compress the feedstock.

Abstract: Process and apparatus for the purification of a gaseous flow containing at least one impurity which can be carbon dioxide, water vapor and/or hydrocarbon. The impurity is adsorbed on a bed of adsorbent containing at least one adsorbent material, it being possible to use stacked adsorbent beds. Atop the uppermost bed is a layer of particulate ballast having a density greater than that of the adsorbent. The bed of ballast exerts a mechanical pressure on the subjacent adsorbent and prevents fluidization of the upper portion of the subjacent adsorbent. As a result, the rate of gas flow through the adsorbent can be increased.

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

Abstract: A method is described for providing clean air at desired temperature to an environment. Incoming air possibly contaminated with nuclear biological and chemical contaminants is compressed. The compressed air is cooled in a first heat exchanger. The cooled air from the first heat exchanger is compressed in a secondary compressor. Compressed air from the secondary compressor is cooled in a second heat exchanger. Cooled air from the secondary heat exchanger is directed through a regenerative pressure swing absorption system to provide clean output air with the contaminants removed therefrom. This cleaned air is expanded in a turbine coupled to the secondary compressor, whereby to recover energy from the cleaned air to drive the secondary compressor. The expanded cleaned air from the turbine is utilized to condition air in the environment. The regenerative pressure swing absorption system is purged with air derived from the expanded clean air.

Abstract: Industrial grade carbon dioxide may contain unacceptable amounts of sulfur-containing materials, oxygen, and organic materials particularly detrimental to food-related uses of carbon dioxide. These can be effectively removed by a bed of silver-exchanged faujasite and an MFI-type molecular sieve. This permits an on-site, on-demand method of purifying carbon dioxide ranging from laboratory to tank car seals.

Abstract: Pelletized adsorbent compositions and methods of adsorbing toxic target compounds are provided for the destructive adsorption or chemisorption of toxic or undesired compounds. The pelletized adsorbents are formed by pressing together powder nanocrystalline particles comprising a metal hydroxide or a metal oxide at pressures of from about 50 psi to about 6000 psi to form discrete self-sustaining bodies. The pelletized bodies should retain at least about 25% of the surface area/unit mass and total pore volume of the starting metal particles.

Abstract: This invention relates to the manufacture of a molecular sieve adsorbent for selectively separating methane from its gaseous mixture with nitrogen. More particularly, the invention relates to the manufacture of novel molecular sieve adsorbents useful for the separation of methane-nitrogen gaseous mixture.

Abstract: Process for purifying an inert fluid, in particular argon or helium, with respect to at least one of its impurities nitrogen (N.sub.2), oxygen (O.sub.2), carbon dioxide (CO.sub.2), carbon monoxide (CO) and hydrocarbons, in which at least some of the impurities are removed using a first adsorbent of the X zeolite type having a silica to aluminum ratio less than or equal to 1.15, and a purified inert fluid containing at most 10 ppb, preferably at most 1 ppb of impurities is recovered.

Abstract: A feedstream comprising nitrous oxide is purified by a pressure swing adsorption process employing a copurge with an oxygen-lean stream to produce a high purity nitrous oxide stream. The high purity nitrous oxide stream can be incorporated in a complex for the production of adipic acid to recover nitrous oxide from a dilute waste stream and pass the recovered nitrous oxide to a process for the production of phenol from an aromatic hydrocarbon. Unreacted nitrous oxide from the phenol production step acid can be recovered in a second, or vent PSA step, and combined with the recovery of byproduct nitrous oxide waste streams from the production of adipic for the overall recovery of nitrous oxide, thereby significantly reducing nitrous oxide emissions from the production of adipic acid.

Abstract: The purge and trap procedure commonly used for analysis of volatile organic compounds in water or air can be significantly improved using traps employing clays and modified clays as adsorbents. Examples of clays include attapulgite clay, attapulgite clay modified with tetrasodiumpyrophosphate, carboxymethylcellulose and the combination thereof, kaolin clay, kaolin clay modified with tetrasodiumpyrophosphate, carboxymethylcellulose or the combination thereof, and mixtures of the above clays.

Abstract: A process for removing sulfur-containing compounds and halocarbons such as fluorocarbons and chlorocarbons from gases to provide gas streams which contain these compounds at unprecedentedly low levels using an adsorption train of four beds has been developed. The first bed serves to remove water, the second and third beds remove sulfur-containing compounds generally, and the fourth adsorbent bed removes sulfur-containing compounds and halocarbons such as chlorocarbons and fluorocarbons to very low levels.

Abstract: The production of naphtha gas from landfill gas is preferably accomplished through a gas purification step, a catalytic conversion of methane gas to hydrogen gas, and a blending step in which various process streams are blended to produce the naphtha gas stream. The landfill gas stream is first treated through a gas purification/separation procedure to produce a substantially pure methane stream. The purified methane stream is then split into at least two portions. The first portion is fed into a hydrogen reformer and a shift reactor, where the methane gas is converted into a hydrogen-bearing stream which includes hydrogen and carbon dioxide. The second portion of the stream is preferably fed into a mixer. In the mixer, the pure methane stream, the hydrogen-bearing stream and a portion of the purified landfill gas stream are preferably blended together to form a naphtha gas stream.

Abstract: A method of treating a gaseous hydrocarbon contained in waste gas by using adsorbent layers of single-tower or multi-tower configuration is characterized in that (1) double-cylinder type or multi-cylinder type adsorption apparatus, in which each adsorbent layer is indirectly cooled by cooling water, are employed as adsorption apparatus; (2) each adsorbent layer is a packed layer of one or more kinds of materials selected from activated carbon, synthetic zeolites and hydrophobic silica gel; (3) swing time required for switching between adsorption and desorption processes is set to 1 to 15 minutes; (4) each adsorbent layer is evacuated under vacuum while being purged by using part of clean gas evacuated from each adsorbent layer and/or air in the desorption process; and (5) the gaseous hydrocarbon is recovered from outflow purge gas. This method makes it possible to prevent abnormal temperature increase within each adsorbent layer and enhance the safety of the apparatus.

Abstract: A method and apparatus are provided for the separation of non-polar organic molecules from fluids which utilize certain hydrocarbon block copolymers having soft and hard segments as absorbents. By employing hydrocarbon block copolymer having a particular concentration of soft and hard segments, optimum absortion is achieved while maintaining the mechanical structure of the absorbent so that it can withstand high fluid flow rates.

Abstract: A method for removing volatile organic compounds (VOCs) from an effluent or exhaust stream produced by an industrial or commercial process that allows for both adsorption and catalytic destruction of the VOCs. The method utilizes a bed containing both adsorbent material and catalytic material, either as an admixture or as separate layers of the two materials. During the preferred mode of operation, one section of the bed collects VOCs from the effluent while simultaneously, in another section of the bed, collected VOCs are destroyed and the bed material is regenerated. This process can continuously eliminate VOCs from an effluent without interruption by rotating the bed through the adsorption and regeneration zones or by rotary feeding of the effluent and an oxygen containing gas to different portions of the bed.

Abstract: A method for generating electric power from natural gas or the like that has a low Btu value and a high nitrogen content. The method involves a membrane separation step to remove a portion of the nitrogen from the gas. The upgraded gas is used as fuel for a turbine or other driver, which provides mechanical power to drive an electric power generator.

Abstract: An apparatus and method for removing volatile organic compounds (VOCs) from a stream of contaminated air using an adsorbent material. The stream of contaminated air is introduced into an end of a first hollow member which contains the adsorbent material. A perforated member disposed within the hollow member is configured to increase the air stream velocity such that dispersed particles of the adsorbent material are entrained in the air stream. Entrainment of the adsorbent in the contaminated air stream facilitates efficient removal of the VOCs. The cleaned air stream exits from a second end of the first hollow member, and the adsorbent material, having a quantity of VOCs adsorbed thereon, is directed to a reconditioning apparatus wherein the VOCs are thermally desorbed. The reconditioned adsorbent material is then returned to the first hollow member.

Abstract: The invention comprises a PSA apparatus for the separation of a heavy component from a light component in a feed stream. The apparatus includes an adsorbent bed comprising either a mixture of adsorbents or composite adsorbent particles wherein each particle comprises two or more adsorbents. At least one of the adsorbents is comparatively weak and the other is comparatively strong. Another embodiment of the invention is a PSA prepurifier having a bed of adsorbent material which comprises a mixture of, or composite adsorbent particles wherein each particle comprises at least two adsorbents, at least one of the adsorbents being comparatively strong and at least another of the adsorbents being comparatively weak.