Abstract: A process for recovering organic components from gas streams by condensation. The process uses a semipermeable separation membrane as an expansion device to provide cooling for condensation.

Abstract: A process for separating two low-boiling components of a gas-phase mixture. The invention involves three separation steps: condensation, flash evaporation and membrane separation. The steps are integrated together in such a way as to provide a good separation between the components, and to avoid creation of secondary streams that need additional treatment. The invention is particularly useful for separation of low molecular weight organic compounds from other gases.

Abstract: A staged adsorbent membrane system is operated to separate a gas mixture wherein more strongly adsorbed secondary components preferentially adsorb and permeate through the adsorbent membrane in the first stage. Less strongly adsorbed primary components are recovered therefrom in a nonpermeate gas product stream. Preferably two stages are utilized wherein the permeate gas from the first stage is introduced into the second stage and the nonpermeate gas from the second stage is recycled to the first stage as additional feed gas to increase the overall recovery and/or purity of the nonpermeate gas product. The two-stage membrane system is operated such that the ratio of the recovery of the primary component in the first stage to the recovery of the primary component in the second stage is less than about 1.0. The method is particularly useful for the recovery of hydrogen from hydrogen-containing gas mixtures.

Abstract: A device and method for selectively removing one or more components from a multicomponent gas/vapor mixture by membrane fractionation. The membrane fractionation gas removal system preferably comprises: a feed chamber which contains the gas/vapor mixture; at least one porous membrane having a first side which contacts the gas/vapor mixture in the feed chamber, and a second side; at least one nonporous membrane having a first side which contacts the second side of the at least one porous membrane, and a second side, the nonporous membrane having a permeability selective to one or more components; an exit chamber connected to the second side of the at least one nonporous membrane such that the component exiting the nonporous gas enters the exit chamber; and an evacuation member connected to the exit chamber for evacuating one or more components from within the exit chamber.

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 homogeneous membrane or an asymmetric membrane which is made of polyimide resin containing fluorine as a main component and has high separation and permeation properties, is used in a method of separating unsaturated hydrocarbon from a mixture of unsaturated and saturated hydrocarbon. The method includes the steps of contacting the mixture onto the membrane made of the polyimide resin having a repeating unit shown in the following formula as a main component, selectively permeating unsaturated hydrocarbon through the membrane, and separating unsaturated hydrocarbon from the mixture. The membrane satisfies the condition of a solubility coefficient ratio between unsaturated and saturated hydrocarbon.gtoreq.1.2 at 25.degree. C. and more than 50 Torr when the absorption of hydrocarbon to the polyimide resin is in equilibrium.

Abstract: A process and apparatus for purification and compression of raw landfill gas stream in a landfill to produce vehicle grade fuel. After the landfill gas stream is extracted and collected, all solids and significant moisture are removed in a pretreatment system prior to compression of the gas stream. The gas stream is then compressed to enhance the function of a membrane purification system. Additional moisture and compressor oil are removed. The gas stream is then heated to maintain any remaining moisture in vapor form. Volatile organic compounds and the balance of the compressor oil are removed from the gas stream by passing the gas stream across an activated carbon guard bed system. The resultant gas stream is fed to a multi-stage membrane system which separates the methane from the other constituents of the landfill gas stream including any remaining moisture.

Abstract: A separation membrane useful for gas separation, particularly separation of C.sub.2+ hydrocarbons from natural gas. The invention encompasses the membrane itself, methods of making it and processes for using it. The membrane comprises a polymer having repeating units of a hydrocarbon-based, disubstituted polyacetylene, having the general formula: ##STR1## wherein R.sub.1 is chosen from the group consisting of C.sub.1 -C.sub.4 alkyl and phenyl, and wherein R.sub.2 is chosen from the group consisting of hydrogen and phenyl. In the most preferred embodiment, the membrane comprises poly(4-methyl-2-pentyne) ?PMP!. The membrane exhibits good chemical resistance and has super-glassy properties with regard to separating certain large, condensable permeant species from smaller, less-condensable permeant species. The membranes may also be useful in other fluid separations.

Abstract: A process for separating the components of a gas mixture, including a sterilant gas and a diluent gas is disclosed. The gas mixture is fed to a membrane separation unit within which a perm-selective membrane is located which allows migration of diluent gas and sterilant gas at different rates. Both sterilant-rich and diluent-rich gas streams are withdrawn from the membrane separation unit and optionally recovered or further processed to a less hazardous compound. The process may be utilized to separate and treat the constituents of the exhaust gases from a chemical sterilization process of which the common components are olefin oxides such as ethylene oxide as a sterilant and chlorofluorocarbons (freon) such as dichlorodifluoromethane (CFC-1) as a diluent.

Abstract: A process for separating hydrocarbon gases of low boiling point, particularly methane, ethane and ethylene, from nitrogen. The process is performed using a membrane made from a super-glassy material. The gases to be separated are mixed with a condensable gas, such as a C.sub.3+ hydrocarbon. In the presence of the condensable gas, improved selectivity for the low-boiling-point hydrocarbon gas over nitrogen is achieved.

Abstract: This invention relates to a method of and apparatus for separating component gases in a gas mixture employing a glassy polymer membrane at temperatures of 5.degree. C. or less so as to achieve superior separation of gas components.

Abstract: A membrane separation process for treating a gas stream containing methane and nitrogen, for example, natural gas. The separation process works by preferentially permeating methane and rejecting nitrogen. We have found that the process is able to meet natural gas pipeline specifications for nitrogen, with acceptably small methane loss, so long as the membrane can exhibit a methane/nitrogen selectivity of about 4, 5 or more. This selectivity can be achieved with some rubbery and super-glassy membranes at low temperatures. The process can also be used for separating ethylene from nitrogen.

Abstract: A membrane and process for separating unsaturated hydrocarbons from fluid mixtures. The membrane and process differ from previously known membranes and processes, in that the feed and permeate streams can both be dry, the membrane need not be water or solvent swollen, and the membrane is characterized by a selectivity for an unsaturated hydrocarbon over a saturated hydrocarbon having the same number of carbon atoms of at least about 20, and a pressure-normalized flux of said unsaturated hydrocarbon of at least about 5.times.10.sup.-6 cm.sup.3 (STP)/cm.sup.2 .multidot.s.multidot.cmHg, said flux and selectivity being measured with a gas mixture containing said unsaturated and saturated hydrocarbons, and in a substantially dry environment.

Abstract: A membrane separation process combined with a cryogenic separation process for treating a gas stream containing methane, nitrogen and at least one other component. The membrane separation process works by preferentially permeating methane and the other component and rejecting nitrogen. The process is particularly useful in removing components such as water, carbon dioxide or C.sub.3+ hydrocarbons that might otherwise freeze and plug the cryogenic equipment.

Abstract: An apparatus reduces the pressure in a volatile chemical tank ullage including a first conduit for connection to the volatile chemical tank ullage, a vapor extractor, a pressure sensor to detect the pressure in the volatile chemical tank ullage, a separation module having an inlet connected to the first conduit, a separation membrane, a permeate outlet separated from the inlet by the separation membrane, and a retentate outlet, a second conduit connected to the permeate outlet for connection to the volatile chemical tank, a vapor pump associated with the second conduit for creating a low pressure in the separation module near the permeate outlet as to induce selected vapors to pass through the separation membrane, a vent associated with the retentate outlet to vent retentate to atmosphere, a VOC detector to detect VOC concentrations in the vent, and a controller to receive inputs from the pressure sensor and the VOC detector and output control signals to the vapor extractor and the vapor pump to pull vapor fr

Abstract: A process for the removal of at least one non-water vapor component of a vaporous mixture, the basic process comprising directing a vaporous mixture against the feed side of a membrane, directing a condensable vapor sweep stream past the permeate side of the membrane in a manner such that the flow of the condensable vapor sweep is substantially countercurrent to the flow of the vaporous mixture, thereby transporting at least a portion of at least one non-water vapor component of the vaporous mixture from the feed side to the permeate side of the membrane to form a combined permeate side mixture of condensable vapor and at least one non-water vapor transported component.

Abstract: A gas-separation method for controlling vapor emissions. The method employs a spiral-wound membrane module, adapted to provide one or more feed-side baffles in the feed channel. The method may be used to control vapor emissions from a volatile liquid, and is particularly useful to control fuel vapors emitted during fuel transfer operations.

Abstract: A method for removing condensable organics from a fluid is disclosed. A fluid contaminated with condensable organics is provided. A poly (alkyl sulfone) permeable membrane having a selectivity.gtoreq.20 is provided. The fluid is passed along a surface of the membrane. The organics permeate through the membrane. The permeated organics are recycled.

Abstract: An apparatus reduces the pressure in a volatile chemical tank ullage including a first conduit for connection to the volatile chemical tank ullage, a vapor extractor, a pressure sensor to detect the pressure in the volatile chemical tank ullage, a separation module having an inlet connected to the first conduit, a separation membrane, a permeate outlet separated from the inlet by the separation membrane, and a retentate outlet, a second conduit connected to the permeate outlet for connection to the volatile chemical tank, a vapor pump associated with the second conduit for creating a low pressure in the separation module near the permeate outlet as to induce selected vapors to pass through the separation membrane, a vent associated with the retentate outlet to vent retentate to atmosphere, a VOC detector to detect VOC concentrations in the vent, and a controller to receive inputs from the pressure sensor and the VOC detector and output control signals to the vapor extractor and the vapor pump to pull vapor fr

Abstract: In a method for separating a gas mixture above a liquid a separating device with a gas separation membrane having retentate side and a permeate side is employed. A vacuum at the retentate side of the gas separation membrane and a vacuum at the permeate side of the gas separation membrane are provided. The gas mixture, resulting from transferring a liquid from one storage container to another container upon contact with the surroundings, is fed to the retentate side of the gas separation membrane by the vacuum present at the retentate side and the permeate side. The flow volume per time unit of the gas mixture fed to the separating device is greater than a flow volume per time unit of the liquid being transferred. On the retentate side of the gas separation membrane a gas-diminished retentate is generated and on the permeate side of the gas separation membrane a gas-enriched permeate is produced.

Abstract: A composite semipermeable membrane comprising microporous adsorbent material supported by a porous substrate is utilized to separate hydrogen-hydrocarbon mixtures and a sweep gas comprising some of the same hydrocarbons is passed across the low pressure side of the membrane to enhance hydrocarbon permeability. Methane is an effective sweep gas which promotes the permeation of heavier hydrocarbons even when methane is present in the membrane feed.

Abstract: A process for separating C.sub.3 + hydrocarbons, particularly propane and butane, from natural gas. The process uses a poly(trimethylsilylpropyne) membrane.

Abstract: A fluid mixture from which an unsaturated hydrocarbon has to be separated, is passed in the first stage at superatmospheric pressure to one side of a first semiselective gas separation membrane with a non-porous active layer, and a liquid complexing agent is passed along the other side of said first membrane, where said unsaturated hydrocarbon is bound through complexation in the interface of membrane and complexing agent. In the second stage said unsaturated hydrocarbon is dissociated from the complexing agent through temperature increase, the mixture of complexing agent and dissociated unsaturated preferably is passed at superatmospheric pressure to one side of a second semiselective membrane with a non-porous active layer and the unsaturated hydrocarbon migrates to the other side of the membrane and is discharged. Finally, the complexing agent is recycled.

Abstract: This invention is directed to a method and system for extracting a solute from a fluid or a dense gas using a porous membrane. The invention includes providing a porous membrane having opposite sides in a module under pressure, with the membrane serving as a barrier interface between a fluid and a dense gas. The dense gas is introduced into the module on one side of the membrane and the fluid is introduced on the opposite side of the membrane. At least one of the fluid and dense gas contains a solute to be extracted, and the other one of the fluid and dense gas serves as an extracting medium. The dense gas has a density of at least about 0.5 g/cc and is essentially immiscible in the fluid so as to provide two phases. The process is conducted with the pressure on both sides of the membrane in the module being essentially the same, and the solute is extracted across the membrane as driven by the concentration gradient of the solute across the membrane.

Abstract: Flaw-free porous ceramic membranes fabricated from metal sols and coated onto a porous support are advantageously used in gas phase fractionation methods. Mean pore diameters of less than 40 .ANG., preferably 5-20 .ANG. and most preferably about 15 .ANG., are permeable at lower pressures than existing membranes. Condensation of gases in small pores and non-Knudsen membrane transport mechanisms are employed to facilitate and increase membrane permeability and permselectivity.

Abstract: There is disclosed a method for removing a volatile component from a feed or process stream comprising (1) absorbing or adsorbing the volatile component into an absorbent or adsorbent material in an equilibrium process, wherein feed is pumped through a mixture chamber of a device, wherein the device comprises the mixture chamber and a vapor chamber, wherein the mixture chamber comprises a plurality of films comprising absorbent or adsorbent materials, wherein the film is configured to have a first side communicating with the mixture chamber and a second side communicating with the vapor chamber, and (2) removing the volatile component from the absorbent or adsorbent material by applying heat to the mixture chamber and simultaneously applying a gas phase within the vapor chamber such that the volatile component is collected in a gaseous state in the vapor chamber.

Abstract: An apparatus and method for maintaining a desired pressure within a fuel storage tank or tanks while minimizing or eliminating the amount of pollutants discharged from the fuel storage tank(s). A fuel storage tank is provided with a conduit and a chamber interfaced along the path of the conduit such that all fluid passing through the conduit must pass through the chamber. A fractionating membrane is housed within the chamber for capturing pollutants while allowing air to pass through. As pollutants are collected on the fractionating membrane, they permeate, thereby reducing the pressure in the tank and associated conduit. A vapor pump is provided for drawing vapor through the conduit and the membrane, and for drawing pollutants off of the membrane. A pressure transducer located in the tank or associated piping makes the vapor pump responsive to the pressure therein. A vent is further provided for allowing air into the tank and piping and for depressurizing the tank and piping.

Abstract: Recovery of hydrogen from hydrogen-containing gas mixtures by pressure swing adsorption is increased by utilizing an adsorbent membrane to concentrate hydrogen in the pressure swing adsorption reject gas and recycling the resulting hydrogen-enriched stream to the feed of the pressure swing adsorption system. Lower compression requirements are realized compared with the use of polymeric membranes for the same service because the hydrogen-enriched stream is recovered from the adsorbent membrane as nonpermeate at essentially the membrane feed pressure. Simultaneous permeation of carbon dioxide and methane occur in the adsorbent membrane, which can be operated at feed pressures as low as 5 psig when hydrogen is used as a sweep gas.

Abstract: To recover liquid methane from a feed gas mixture (1) essentially consisting of methane, C.sub.2+ hydrocarbons, carbon dioxide and nitrogen, the feed gas mixture (1) is fed first to an adsorption unit (E) and freed from water; dried feed gas mixture (2) is fed to a membrane separating unit (F), wherein the carbon dioxide is separated down to a residual content less than 2% by volume (9) and resultant gas mixture (3) now essentially consisting of methane, C.sub.2+ hydrocarbons and nitrogen is fed to a low-temperature distillation (A) wherein the C.sub.2+ hydrocarbons as well as the residual content of carbon dioxide are separated by distillation.

Abstract: A device and method for removing, concentrating and analyzing airborne organic compounds. The device includes a nonporous membrane which contains a collection media. The liquid collection media typically includes a component which has a molecular weight that is too large to pass through transport corridors in the nonporous membrane and a component which has a molecular weight which is sufficiently small enough to pass through the transport corridors in the nonporous membrane and thereby forming a thin film on the exterior surface of the device. The collection media can consist of only components too large to pass through the membrane transport corridors. Organic contaminants are trapped in the thin film on the exterior surface of the device or the membrane and transported by concentration gradient diffusion forces into the bulk of the collection media within the nonporous membrane.

Abstract: Apparatus for preconcentrating trace amounts of organic vapors in a sample of air for subsequent detection, comprising a metallic substrate; a thin film of fullerenes deposited on the metallic substrate for adsorbing the organic vapors on the thin film of fullerenes, thereby preconcentrating the organic vapors; and apparatus for heating the metallic substrate to a predetermined optimum temperature for desorbing the vapors from the thin film of fullerenes to form desorbed organic vapors for subsequent detection.

Abstract: A process for treating a gas stream to remove or recover a condensable component. The process involves a condensation step followed by a membrane concentration step. The process is useful in treating raw gas streams containing low concentrations of the condensable component, in treating small-volume raw gas streams, as an alternative to processes that require multistage membrane separation systems, in treating raw gas streams that have the potential to form explosive mixtures, or in situations where the treated gas stream composition must meet narrow target specifications.

Abstract: Mixtures of hydrogen and hydrocarbons may be separated by a membrane formed of a thin dense layer of platinum or palladium on the inside of a porous graphite tube.

Abstract: A composite semipermeable membrane comprising microporous adsorbent material supported by a porous substrate is operated in series with a pressure swing adsorption (PSA) system and the PSA reject gas is used as a sweep gas to improve membrane performance. The integrated membrane-PSA system is particularly useful for recovering high-purity hydrogen from a mixture of hydrogen and hydrocarbons, and is well-suited for integration with a steam-methane reformer.

Abstract: A method is disclosed for separating a multicomponent gas mixture comprising at least three components into three product streams by use of adsorbent membrane zones operating in series. Each product is enriched in a different component based upon the relative strength of adsorption of each component on the adsorbent material. A non-permeate primary component product is obtained by the selective adsorption and permeation through the adsorbent membranes of secondary components which are more strongly adsorbed than the primary components in the gas mixture. Two or more permeate streams enriched in the more strongly adsorbed components are withdrawn from the membrane zones as individual secondary products, each of which contains a different component distribution determined by the relative strength of adsorption of the secondary components on the adsorbent material.

Abstract: A method of treating sour liquefied petroleum gas comprising removing hydrogen sulfide from the sour liquefied petroleum gas by:(a) contacting the liquefied petroleum gas in an extraction column with a liquid and regenerable absorbent to obtain purified liquefied petroleum gas;(b) supplying the purified liquefied petroleum gas to a membrane unit comprising a membrane selected from a permselective membrane and a porous hydrophobic membrane, a permeate outlet and a retentate outlet; and(c) removing from the permeate outlet of the membrane unit treated liquefied petroleum gas and from the retentate outlet of the membrane unit contaminated liquefied petroleum gas.

Abstract: A process for separating condensable organic components from gas streams. The process makes use of a membrane made from a polymer material that is glassy and that has an unusually high free volume within the polymer material.

Abstract: A process for removing organic compounds from water is disclosed. The process involves gas stripping followed by membrane separation treatment of the stripping gas. The stripping step can be carried out using one or multiple gas strippers and using air or any other gas as stripping gas. The membrane separation step can be carried out using a single-stage membrane unit or a multistage unit. Apparatus for carrying out the process is also disclosed. The process is particularly suited for treatment of contaminated groundwater or industrial wastewater.

Abstract: A porous membrane comprising a porous substrate and a tin oxide-containing material in contact with at least a portion of the porous substrate.

Abstract: A method and apparatus for removal of gaseous epoxides from effluent gas streams is described. The method comprises contacting a gaseous sample suspected of containing gaseous epoxides with a polymer barrier. The polymer barrier is comprised of a superactidic perfluorinated alyl sulfonic acid polymer that is capable of converting a gaseous epoxides to gaseous non-epoxide products. Specifically, the method is capable of removing ethylene oxide and propylene oxide from effluent gas streams with greater than 90% efficiency.

Abstract: A process for removing and recovering a condensable vapor from a gas stream by a membrane contactor is disclosed wherein a gas stream containing a condensable vapor is circulated on one side of hollow fiber membranes while cool extraction fluid is circulated on the other side under a total pressure differential, thereby condensing the condensable vapor in the gas stream, the condensed vapor permeating the membrane and becoming entrained in the cool extraction fluid.