Abstract: Solvent-resistant polybenzimidazole membranes, methods of making them and crosslinking them and composite membranes and hollow fiber membrane modules from them are disclosed.

Abstract: A compressed gas system utilizing a membrane air dryer is shown wherein, during unloading, additional sweep gas is provided to the membrane air dryer to prevent excess moisture from being introduced into the accumulator at the end of each unloading cycle. A membrane air drier for use in such system is also described.

Abstract: A hydrogen diffusion cell that is used to purify contaminated hydrogen gas. The hydrogen diffusion cell has a supply tube that supplies contaminated hydrogen gas into a confined area and a drain tube that removes contaminated hydrogen gas from the confined area. Hydrogen permeable coils are disposed between the supply tube and the drain tube. The hydrogen permeable coils surround a perforated output tube that draws in any hydrogen gas that diffuses through the hydrogen permeable coils. The presence and position of the output tube prevent any significant lateral movement of hydrogen gas within the diffusion cell.

Abstract: Porous hollow polymer fiber membranes having convoluted inside and/or outside surfaces, as well as filter devices comprising a plurality of the hollow fiber membranes, the devices preferably being arranged to direct fluid flow from the inside surface of the membranes to the outside surface, methods of making the membranes, and methods of using the filter devices, are disclosed.

Abstract: Porous asymmetric hollow polymer fiber membranes having spiraled inner and/or outer surfaces, as well as filters and filter devices comprising one or more of the hollow fiber membranes, the filter and devices preferably being arranged to direct fluid flow from the inner surface of the membranes to the outer surface, and methods of using the filters and filter devices, are disclosed.

Abstract: A composition of and a method of making high performance mixed matrix hollow fiber membranes is described. The membranes have a high resistance to plasticization by use of a predetermined amount of crosslinking. The preferred polymer material for the membrane is a polyimide polymer continuous phase comprising ester crosslinks and a molecular sieve material dispersed within the polymer continuous phase. The resultant mixed matrix hollow fiber membrane exhibits a high permeance of CO2 in combination with a high CO2/CH4 selectivity. Another embodiment provides a method of making the mixed matrix hollow fiber membrane from a monesterified polymer followed by final crosslinking after hollow fiber formation.

Abstract: A composition of and a method of making high performance mixed matrix hollow fiber membranes is described. The membranes have a high resistance to plasticization by use of a predetermined amount of crosslinking. The preferred polymer material for the membrane is a polyimide polymer contineous phase comprising ester crosslinks and a molecular sieve material dispersed within the polymer contineous phase. The resultant mixed matrix hollow fiber membrane exhibits a high permeability of CO2 in combination with a high CO2/CH4 selectivity. Another embodiment provides a method of making the mixed matrix hollow fiber membrane from a monesterified polymer followed by final crosslinking after hollow fiber formation.

Abstract: A combined hot gas cleanup system and gas separation unit is contained within a single pressure vessel. Preferably, the combined unit is an integral structure that is retrofittable to replace existing candle filters in their installed holders. The integral unit can be replaced to adapt the combined system for different applications.

Abstract: A composition of and a method of making high performance hollow fiber membranes is described. The membranes have a high resistance to plasticization by use of a predetermined amount of crosslinking. The preferred polymer material for the membrane is a polyimide polymer comprising ester crosslinks. The resultant hollow fiber membrane exhibits a high permeability of CO2 in combination with a high CO2/CH4selectivity. Another embodiment provides a method of making the hollow fiber membrane from a monesterified polymer followed by final crosslinking after hollow fiber formation.

Abstract: A method for fabricating a composite membrane includes coating a substrate, such as, for example, an asymmetrical porous hollow fiber substrate, with a solution which includes a perfluorinated polymer and a perfluorinated solvent. Prior to coating, the substrate is impregnated with an impregnation fluid which is immiscible with the perfluorinated solvent. The method of the invention further includes removing the perfluorinated solvent and the impregnation fluid. A composite membrane includes a porous asymmetric hollow fiber substrate having an outer surface coated with a perfluoropolymer coating. Separation devices which include composite membranes and methods of separating a fluid mixture into a fraction enriched in a first component and a fraction depleted in that component also are described.

Abstract: A membrane air drier utilizes an orifice to serve as the sweep air inlet with a sweep diffuser placed a short distance from the orifice. Preferably, an open channel extends from the product end of the membrane module on the shell side of the fibers with a porous diffuser at one end of the open channel and an orifice at the other end of the channel.

Abstract: A breathable, stretch-thinned barrier film having improved strength, processability and/or breathability is formed from a mixture of a thermoplastic polymer and cavated filler particles such as cyclodextrin. The cavated filler particles provide the film with enhanced breathability to water vapor due to their ring-like, conical, cylindrical or otherwise hollow molecular structure, yet the film remains substantially impermeable to aqueous liquids. The enhanced breathability occasioned by the cavated particles permits the use of relatively low filler levels and correspondingly high polymer levels, thereby enhancing the film strength. The filler may melt during extrusion of the molten polymer into a film, facilitating smooth processing, and re-crystallize into particles after the film is formed and cooled.

Abstract: A high carbon content membrane and method for making the same are disclosed. The carbon membrane includes an asymmetric hollow filamentary carbon membrane, including a partial carbonization product of an asymmetric hollow filament including an aromatic imide polymer material. The carbon membrane is at least 95 weight percent carbon, and has a dense layer located in the outside surface portion of the hollow filamentary membrane and a porous base layer continued from the dense layer and located in the inside portion of the hollow filamentary membrane. A process for separating CO2 from natural gas is described including: contacting a mixture of CO2 and natural gas with a first side of a carbon membrane in a manner to cause a portion of the mixture to pass through the carbon membrane to a permeate side. The resulting mixture on the permeate side becomes enriched in CO2 over that of the mixture on the first side. The contacting step occurs at a pressure of at least about 200 psia.

Abstract: An ion-transport membrane assembly including a tubular, ion-transport membrane that is fabricated from one or more ion-transport, ceramic materials capable of ionic transport at an operational temperature of greater than 400° C. The membrane may be an oxygen transport membrane or a hydrogen transport membrane. A plurality of structural supporting members, fabricated from an open porous material and having an outer cylindrical surface, are inserted within the membrane, without being bonded to the membrane, to inhibit inward collapse of the membrane under application of a pressure applied to an exterior surface of the membrane. The structural supporting members are configured to permit relative movement between the outer surface of the structural supporting member and the interior surface of the tubular membrane during heating to or cooling from the operational temperature thereof.

Abstract: Mixed matrix membranes capable of separating carbon dioxide from mixtures including carbon dioxide and methane, and processes for purifying methane using the membranes, are disclosed. The membranes are preferably polymer membranes, that include discrete carbon-based molecular sieve particles with sizes of between about 0.5 microns to about 5.0 microns. The particles are formed by pyrolyzing a precursor polymer in the form of a powder or film. The pyrolyzed polymer is then ideally milled to desired small size particles. The preferred ratio of particles to polymer is about 0.25 to about 1.0 by volume. A preferred method for preparing the mixed matrix membrane is by dispersing the particles in a solvent, adding a small quantity of the desired polymer or “sizing agent” to “size” or “prime” the particles, adding a polymer, casting a film of the polymer solution, and evaporating the solvent to form a mixed matrix membrane film.

Abstract: A method and system is provided for combusting a fuel having application to a heat consuming device such as a boiler or furnace or a reactor. An oxygen-containing stream is introduced into one or more oxygen transport membranes subjected to a reactive purge or a sweep gas. The oxygen transport membrane(s) can advantageously be subjected to a reactive purge or a sweep gas passing in a cross-flow direction with respect to the membranes to facilitate separation of the oxygen. In case of a reactive purge, temperature control of the oxygen transport membrane(s) is effectuated by the use of a suitable heat sink. Further, the oxygen transport membranes can be arranged in a row and be connected in series such that retentate streams of ever lower oxygen concentrations are passed to successive oxygen transport membranes in the row. The fuel or sweep gas can be introduced in a direction counter-current to the bulk flow of the retentate streams.

Abstract: The invention is directed to a silver/palladium (AgPd) cell for adjusting or measuring a level of hydrogen in a high pressure environment, a high temperature environment, and/or an environment incompatible with stainless steel. The inventive cell includes a hollow diffusion tube of a AgPd alloy operably associated with a hollow connecting member and a connected tube, also operably associated with the hollow connecting member. The cell is operable in environments having a pressure of up to 3,600 p.s.i.

Abstract: A process for making microporous membranes that incorporate selected gas selective species as surface sites in a controlled spacing and orientation manner and such membranes so formed being suitable for separating and purifying the selected gas from selected gas containing gas mixtures. An example is the use of oxygen selective transition element complexes (TECs) as surface sites for separating and purifying oxygen from oxygen-containing gas mixtures.

Abstract: A hollow fiber membrane dehumidification device that possess hollow fiber membranes that cause the compressed air supplied from one end to the interior to flow through and at the same time discharge moisture in the compressed air to the outside, and by so doing exhausts the compressed air to the other end as dehumidified air. There is a reflux route that causes a portion of the dehumidified air exhausted from the hollow fiber membranes to flow back to the outside of the hollow fiber membranes as purged air and a variable restrictor that is provided on the reflux route that increases or decreases the opening-closing volume in accordance with the increase or the decrease of the pressure of the compressed air that flows through the interior of the hollow membranes.

Abstract: A hollow fiber membrane dehumidification device with a housing chamber open to atmosphere via a through hole. Hollow fiber membranes are disposed in the housing chamber and cause compressed air entering from one end to flow through and be discharged at the other end as dehumidified air by discharging moisture to the outside housing chamber. A reflux route is provided to permit a portion of the dehumidified air to flow back to the housing chamber as purged air. First and second orifices are provided on the reflux route wherein the second orifice has an opening diameter larger than that of the first orifice.

Abstract: A method for fabricating a composite membrane includes coating a substrate, such as, for example, an asymmetrical porous hollow fiber substrate, with a solution which includes a perfluorinated polymer and a perfluorinated solvent. Prior to coating, the substrate is impregnated with an impregnation fluid which is immiscible with the perfluorinated solvent. The method of the invention further includes removing the perfluorinated solvent and the impregnation fluid. A composite membrane includes a porous asymmetric hollow fiber substrate having an outer surface coated with a perfluoropolymer coating. Separation devices which include composite membranes and methods of separating a fluid mixture into a fraction enriched in a first component and a fraction depleted in that component also are described.

Abstract: The new hydrogen-recovering device 10 has a box-shaped frame 11 made of stainless steel having a takeout pipe 12 attached to its one side. A plurality of spacers 13 are arranged inside the box-shaped frame 11 along a lengthwise direction of the device 10. A perforated metal plate 14 is fixed to each surface of the box-shaped frame 11, and a hydrogen-permeating membrane 16 cladded with a membrane holder 15 is further fixed to the perforated metal plate 14. Hydrogen gas as a decomposition product of hydrocarbon selectively passes through the hydrogen-permeating membrane 16 and flows through the takeout pipe 12 to the outside. A tubular device, which has the structure that a hydrogen-permeable membrane is fixed to a perforated metal plate wound around a tubular frame, is also proposed. The device 10 is light and strong, so that it is installed in a gas-reforming plant without use of a fixing jig.

Abstract: A new type of silica-modified membrane has been developed by the high-temperature, atmospheric-pressure CVD of Vycor glass. The new membrane, Nanosil, showed unprecedented selectivity to hydrogen (100%), without loss of permeability compared to the porous Vycor precursor. The membrane also showed high stability under hydrothermal conditions over prolonged time. The suitability of a Rh/Al2O3 catalyst for the methane reforming with carbon dioxide was also demonstrated. The limitations imposed by thermodynamics on methane conversion have been circumvented by the use of membranes to preferentially remove hydrogen during reaction. The shortcoming of the Knudsen mode of diffusion was overcome by the development of the modified porous glass membrane.

Abstract: The invention relates to a method for separating a fluid mixture consisting of at least two components. The inventive method comprises the following steps: contacting the fluid mixture at a first, lower temperature in a first operating zone with a carbon membrane which is arranged adjacent to a surface of a porous transport matrix or which is applied on a surface of the matrix, whereby at least one fluid component is adsorbed and at least one component of the fluid mixture preferably permeates the membrane; heating a surface spatially distant from the membrane and/or a part of the porous transport matrix to a second, higher temperature which facilitates the thermal desorption of adsorbed components in a second operating zone; separately removing the fluid mixture depleted by the at least one permeated component from the first operating zone and the fluid mixture enriched with the at least one permeated component from the second operating zone.

Abstract: A hollow fibre membrane has an active layer (2) in which elongate polymer molecules (3) are longitudinally aligned essentially parallel to the extrusion direction to thereby define a plurality of spaced free volume cavities (4) which are particularly numerous and are essentially regularly spaced to provide enhanced selectivity when used in gas separation. The hollow fibre membrane is manufactured using a dry/wet phase separation process by spinning a dope composition which is extruded through a spinneret (12) having an annulus or annular orifice (16) together with a bore-forming fluid or coagulant. The dope composition has a power law index of less than 1 (unity) and the bore coagulant has a water activity of less than 1 (unity).

Abstract: A method for removing a condensable component from a process stream in which a first side of a permselective membrane is contacted with the process stream in which is disposed the condensable component. The condensable component is passed through the permselective membrane to a second side of the permselective membrane, forming a condensable permeate. The condensable permeate is then contacted with a liquid stream having a liquid form of the condensable permeate, forming a condensed permeate. The condensed permeate may then be returned to the process which generated the process stream.

Abstract: Contaiminated hydrogen gas from a catalytic steam reformer is purified by passing it through a membrane assembly having a metallic membrane sealed between two tubular stainless steel members having perforations (or being formed as screen or mesh) and having an encapsulating chamber around it. Pressure regulating valve means in recycle path of residual gas flowing out of the membrane assembly maintains a constant pressure of contaminated hydrogen gas in the membrane assembly. The purified hydrogen gas may be further purified, if needed, by directing the purified hydrogen gas out of a side tube of the chamber through a second encapsulated membrane assembly that is a replica of the first encapsulated membrane assembly. A directional valve may be selectively set to recycle residual gas out of the first membrane assembly until it is virtually free of hydrogen. Residual gas out of the second membrane assembly approaches being 100% free of hydrogen and may always be exhausted to a burner.

Abstract: An exchanger and method for manufacturing the same are disclosed. In one embodiment, the exchanger crimps a hollow fiber bundle along a length of a cylindrical case in at least two radial positions. At least one crimp is between an inlet port and an outlet port of a blood conduit. Preferably, the cylindrical case has two portions with different radii so that when the two portions are mated to enclose the hollow fiber bundle, crimping is achieved. In this way, shunting of blood is avoided by being forced to pass a crimped position between the inlet and outlet ports to more evenly distribute the blood among the fibers of the bundle. In another embodiment, a method for making an exchanger includes filling a chamber, integral to the exchanger, with uncured potting material. The exchanger is spun to distribute the uncured potting material about open ends of an encasement. After curing, a portion of the potting material and the hollow fiber bundle are trimmed away.

Abstract: Mixed matrix membranes capable of separating carbon dioxide from mixtures including carbon dioxide and methane, and processes for purifying methane using the membranes, are disclosed. The membranes are polymer membranes with a selective layer thickness of between about 1000 Angstroms to about 0.005 inch, that include discrete carbon-based molecular sieve particles with sizes of between about 0.5 microns to about 5.0 microns. The preferred ratio of particles to polymer is about 20% to about 50% by volume. A preferred method for preparing the mixed matrix membrane is by dispersing the particles in a solvent, adding a small quantity of the desired polymer or “sizing agent” to “size” or “prime” the particles, adding a polymer, casting a film of the polymer solution, and evaporating the solvent to form a mixed matrix membrane film.

Abstract: Composite membranes capable of separating p-xylene from mixtures including p-xylene and m-xylene, and processes for purifying p-xylene using the membranes, are disclosed. The membranes are polymer membranes with a thickness of between about 10 and 1000 microns that include non-interconnected zeolite particles less than 5 microns. In one embodiment, a relatively thin polymer layer (0.5-3 microns) that includes zeolite particles is adjacent to a relatively thick polymer layer which may or may not include zeolite particles, where the thickness of the two layers is between about 10 and 1000 microns. The preferred ratio of zeolite/polymer is about 0.2 by weight. A preferred method for preparing the composite is by dispersing the zeolite in a polymer solution, casting a film of the polymer solution, and evaporating the solvent to form a polymeric film. The polymer permits passage of p-xylene and m-xylene in the vapor state, such that p-xylene diffuses at the same or a faster rate through the polymer.

Abstract: A process for preparing polyimide gas separation membranes is disclosed. The process involves preparing polyamic acid salt membrane precursors that are converted into polyimide membranes by mild thermal or chemical treatments. The gas separation processes that utilize these polyimide membranes are further disclosed.

Abstract: Process for producing integrally asymmetrical hydrophobic polyolefinic membranes with a separation layer, in particular for gas exchange, via thermally induced liquid-liquid phase separation. A solution of at least one polyolefin in a solvent system containing a compound A and a compound B is extruded to form a shaped object. Compound A is a strong solvent and compound B a weak non-solvent for the polymer. After leaving the die, the shaped object is cooled using a solid or liquid cooling medium, which does not dissolve the polymer and does not react chemically with it, until the phase separation and solidification of the high-polymer-content phase take place.

Abstract: A flow-through vacuum degassing unit for degassing a liquid includes a vacuum chamber adapted to be connected to a source for creating a vacuum in the chamber, an inlet and an outlet connection for admitting and discharging liquid to be degassed, a tube for conducting the liquid through the chamber, wherein the tube is a gas permeable polymeric resin material, and a control circuit for operating the source for creating a vacuum in the chamber responsive to a sensed vacuum level in the chamber.

Abstract: The present invention relates generally to on board inert gas generating systems, and more particularly, to an on board inert gas generating system having a fast warm up feature. Even more particularly, the present invention relates to a method and apparatus for quickly warming up a permeable membrane air separation system.

Abstract: The invention is directed to a method for preparing a membrane comprising a homogeneous porous carrier, on which a layer of a molecular sieve is deposited, comprising the following steps (i) preparing an inert solution and a precursor solution of the molecular sieve; (ii) impregnating the porosity of the carrier with the inert solution and/or the precursor solution; (iii) bringing the region of the ceramic carrier intended to receive the layer of a molecular sieve into contact with the precursor solution, and bringing the region of the carrier not intended to receive the layer of a molecular sieve into contact with the inert solution; and (iv) forming a molecular sieve in situ. The invention applies e.g., to filtration or gas or liquid fluid separation, reverse osmosis or catalysis.

Abstract: A hydrogen diffusion cell that is used to purify contaminated hydrogen gas. The hydrogen diffusion cell has a supply tube that supplies contaminated hydrogen gas into a confined area and a drain tube that removes contaminated hydrogen gas from the confined area. Hydrogen permeable coils are disposed between the supply tube and the drain tube. The coils include at least one small diameter coil. Concentrically surrounding the small diameter coil is at least one larger diameter coil. All coils are mounted in such a manner so that they maintain a constant radius of curvature along their entire lengths.

Abstract: An asymmetric membrane is formed using a mixture of two or more different polymers including at least one type of polyimide. It is thereby possible to produce a gas separation membrane with low permeation resistance (a high permeation rate) for permeate gases passing through the porous layer of the membrane, which also maintains a practical level of mechanical strength of the membrane and has excellent water resistance and hot water resistance.

Abstract: An apparatus for extracting a gas, in particular hydrogen, from a fluid stream utilizing a plate membrane flattened with a wave spring on the low pressure side of the membrane and a turbulence generator on the high pressure side. Alternately, the membrane is folded and wrapped against a central conduit within the membrane fold. Extraction membranes have a substrate layer of Ta—W, V—Co, V—Pd, V—Au, V—Cu, V—Al, Nb—Ag, Nb—Au, Nb—Pt, Nb—Pd, V—Ni—Co, V—Ni—Pd, V—Nb—Pt or V—Pd—Au alloy or combination thereof and a first layer affixed to the outer surface of the substrate towards a mixed gas flow which is composed of palladium, platinum, rhodium, or palladium alloys.

Abstract: A downhole preferential hydrocarbon gas recovery system and method employ preferentially selective materials to separate the hydrocarbon gas from contaminants. According to one aspect of the invention, the preferentially selective materials are arranged in tubes with the hydrocarbon gas flowing through the tubes and the contaminants permeating out through the preferentially selective material.

Abstract: The invention relates to a permeation installation comprising: a single pressure resistant chamber (30), a plurality of permeation modules (34, 36) disposed within the chamber, each module being constituted by at least one permeator formed of hollow fibers with porous walls and being disposed within an envelope (38) provided with perforations placing in communication the external portion of each module and the common gaseous circuit, elements (32) to supply the installation with the gaseous mixture to be treated, elements (46) to recover the fraction of the gaseous mixture having passed through the wall of the fibers; and elements (44) to recover the fraction of the gaseous mixture that has not passed through the wall of the fibers.

Abstract: The present invention provides a gas-permeable hollow fiber membrane having an inner diameter of 50 to 500 &mgr;m, which is preferably a composite hollow fiber membrane having a three-layer structure consisting of a nonporous layer having porous layers disposed on both sides thereof. This membrane can be used to remove dissolved gases present in an ink.

Abstract: The invention is concerned with a device and a process for drying air in ventilation devices for fuel tanks and gas drying in fuel tanks via vapor permeable membranes and sorbents.

Abstract: A multi-channel porous ceramic fiber is provided, preferably having a particular geometry, together with a filtration and/or reaction module comprising such fibers and a precursor paste for the fiber comprising a compression binder as the extrusion binder.

Abstract: A method for dewatering and/or degassing a hydraulic fluid includes separating gases and water in the hydraulic fluid from the hydraulic fluid by pervaporation at a membrane that is permeable to the gas and the water and that is impermeable to hydraulic fluid, while maintaining a partial pressure drop for the gas and the water near the membrane.

Abstract: An unique filtration device (10) which removes acidic contaminants such as H2S and SO2 from a fluid stream through the use of partially hollow wicking fibers (20) impregnated with an effective amount of alkaline-generating chemical compounds, preferably also containing an effective amount of a compound with elements from Group II and Group 6-12 in +2 oxidation state, and most preferably also containing an effective amount of solid fine particles (18). A nonwoven filter mat (12) is formed from a plurality of the elongated fibers (20) each having at least one internal channel (22) connected to the fiber outer surface via an elongated opening (24). The fluid stream containing the acidic gas phase contaminants is directed over the nonwoven filter mat (12) whereby said plurality of small solid particles (18) and reservoir of active chemical reagents disposed in the open channels (22) communicate through the elongated opening (24) with the fluid flow path and absorbs the acidic gas phase contaminants.

Abstract: A partially carbonized asymmetric hollow fiber separation membrane which is a hollow fiber separation membrane having an asymmetric structure obtained by partial carbonization of an aromatic polyimide hollow fiber separation membrane with an asymmetric structure, wherein the thickness of the aromatic polyimide hollow fiber membrane to be partially carbonized is 8-50 &mgr;m, the thickness of the hollow fiber separation membrane obtained by the carbonization is 8-45 &mgr;m, and the carbon content of the hollow fiber membrane obtained by partial carbonization is at least 1.05 times the carbon content of the aromatic polyimide hollow fiber membrane to be partially carbonized, and no greater than 90 wt %; also, a process for its production and a gas separation method employing it.

Abstract: A coating for microporous hollow fiber membrane blood oxygenators increases the resistance of the fibers to passage of blood plasma through the micropores. The coating comprises alkoxysilane/alkylsilane copolymer, preferably aminoalkylsiloxane.

Abstract: A surface modified gas separation membrane having improved permselective properties for separating a mixture of gases as compared to the unmodified membrane, is described. The gas separation membrane is made by a process comprising the steps of coating a surface unmodified gas separation membrane with a solution of a coating material, wherein the coating material is an organic material having at least one site of unsaturation; heating the coated gas separation membrane; and contacting the heated coated gas separation membrane with at least one oxidizing agent for a time effective to surface modify the gas separation membrane to produce the surface modified gas separation membrane having improved permselectivity.

Abstract: Improved polymer blends, and polymer blend membranes having improved mechanical properties are provided by alteration of the critical solution temperature of the polymer blend spinning solution through the incorporation of organic or inorganic complexing agents.

Abstract: The invention relates generally to ceramic oxygen generating modules, and more particularly, to an apparatus and method for controlling a duty cycle for each of a plurality of ceramic oxygen generating modules in a modular ceramic oxygen generating system.