Abstract: A fuel storage system is provided including at least one storage tank, an air exhaust port, a first filter assembly, a primary pump, a least one secondary pump, at least one additional filter assembly, and an additional secondary pump. The first filter assembly includes a filter input port, a fuel vapor duct, a primary filter output port, and a secondary filter output port. The filter input port is coupled to a fluid vent port. The fuel vapor duct defines a substantially unobstructed flow path extending from the filter input port to a primary filter output port. The primary filter output port is coupled to a pollutant return port. The secondary filter output port is partitioned from the fuel vapor duct by an air-permeable partition. The primary pump is positioned to cause fluid to pass from the filter input port to the primary filter output port.

Abstract: A process for the separation and recovery of fluorochemicals from a gas stream containing a diluent gas and fluorochemicals by contact of the gas stream with a membrane system in combination with an adsorption system, the adsorption system used either before or after the membrane system.

Abstract: Processes and systems to recover at least one perfluorocompound gas from a gas mixture are provided. In one embodiment the inventive process comprises the steps of a) providing a gas mixture comprising at least one perfluorocompound gas and at least one carrier gas, the gas mixture being at a predetermined pressure; b) providing at least one glassy polymer membrane having a feed side and a permeate side; c) contacting the feed side of the at least one membrane with the gas mixture; d) withdrawing from the feed side of the membrane as a non-permeate stream at a pressure which is substantially equal to the predetermined pressure a concentrated gas mixture comprising essentially the at least one perfluorocompound gas; and e) withdrawing from the permeate side of the membrane as a permeate stream a depleted gas mixture comprising essentially the at least one carrier gas.

Abstract: Processes and systems to recover at least one perfluorocompound gas from a gas mixture are provided. In one embodiment the inventive process comprises providing a gas mixture comprising at least one perfluorocompound gas and at least one carrier gas, the gas mixture being at a predetermined pressure; providing at least one size selective membrane having a feed side and a permeate side; contacting the feed side of the at least one membrane with the gas mixture; withdrawing from the feed side of the membrane as a non-permeate stream at a pressure which is substantially equal to the predetermined pressure a concentrated gas mixture comprising essentially the at least one perfluorocompound gas; and withdrawing from the permeate side of the membrane as a permeate stream a depleted gas mixture comprising essentially the at least one carrier gas.

Abstract: A process for recovering SF.sub.6 from a gas is provided. The process includes the step of contacting a gas stream comprising SF.sub.6 and at least one of N.sub.2, O.sub.2, CO.sub.2, and H.sub.2 O with a membrane in at least one membrane separation unit at conditions effective to obtain a retentate stream rich in SF.sub.6 and a permeate stream rich in at least one of N.sub.2, O.sub.2, CO.sub.2, and H.sub.2 O.

Abstract: A system for generating oxygen enriched air includes a compressed air supply for supplying compressed air and a permeable membrane gas separation system for separating a nitrogen gas component and an oxygen enriched air component from the compressed air. An oxygen analyzer is provided to detect an oxygen concentration in the oxygen enriched air component. The nitrogen gas component is divided, by a vortex tube, into a cold gas stream and a hot gas stream, and solenoid valves are actuated to modify a flow path of the compressed air through the cold gas stream and the hot gas stream in order to selectively heat and cool the compressed air. The oxygen enriched air is then selectively distributed for further use.

Abstract: The present invention provides a process for recovering sulfur hexafluoride ("SF.sub.6 ") from a gas stream using membrane separation.

Abstract: This invention relates to a method of an apparatus and method for separating component gases in a gas mixture employing a glassy polymer membrane at temperatures at or slightly above the freezing point of any liquid present so as to achieve superior separator of gas components. The composition of certain monomers and polymers are claimed.

Abstract: The present invention provides a process for preparing membranes using novel silicon containing polyarylates of Formula I ##STR1## where R.sub.1 to R.sub.8 represent hydrogen, alkyl groups containing 1 to 5 methylene group or halogen atoms, R.sub.9 and R.sub.10 represents alkyl groups containing 1 to 5 carbon atoms or CF.sub.3 group and R.sub.11 and R.sub.12 represent alkyl groups with 1 to 5 carbon atoms or phenyl groups.

Abstract: A process for recovering at least one of CF.sub.4 and C.sub.2 F.sub.6 from a vent gas from an aluminum electrolysis cell. The process includes the steps of:(a) removing inorganic fluorides from a vent gas comprising inorganic fluorides and at least one of CF.sub.4 and C.sub.2 F.sub.6 to obtain a purified vent gas; and(b) contacting the purified vent gas with a membrane at conditions effective to obtain a retentate stream rich in at least one of CF.sub.4 and C.sub.2 F.sub.6, and a permeate stream depleted in at least one of CF.sub.4 and C.sub.2 F.sub.6.

Abstract: A process for separating perfluoro compound gas or vapor from another gas, typically nitrogen, in a gas mixture. The process involves a combination of membrane separation and condensation, and is particularly useful in the semiconductor industry, for treating exhaust gases from cleaning of chemical vapor deposition chambers. Operation of the condensation step at temperatures no lower than about -30.degree. C. reduces the need for refrigeration equipment and controls the amount of gas dissolved in the recovered perfluoro compound.

Abstract: Processes and systems to recover at least one perfluorocompound gas from a gas mixture are provided. In one embodiment the inventive process comprises the steps of a) providing a gas mixture comprising at least one perfluorocompound gas and at least one carrier gas, the gas mixture being at a predetermined pressure; b) providing at least one glassy polymer membrane having a feed side and a permeate side; c) contacting the feed side of the at least one membrane with the gas mixture; d) withdrawing from the feed side of the membrane as a non-permeate stream at a pressure which is substantially equal to the predetermined pressure a concentrated gas mixture comprising essentially the at least one perfluorocompound gas; and e) withdrawing from the permeate side of the membrane as a permeate stream a depleted gas mixture comprising essentially the at least one carrier gas.

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 method for the separation and recovery of fluorochemicals from a gas stream containing a diluent gas and fluorochemicals by contact of the gas stream with a membrane, comprising the steps of: compressing a gas stream containing a diluent gas and fluorochemicals to an elevated pressure; heating the gas stream containing a diluent gas and fluorochemicals to an elevated temperature sufficient to increase the flux of the permeate stream and to increase the selectivity of the membrane for the permeation of the diluent gas relative to the permeation of the fluorochemicals; contacting the gas stream with a membrane which is selectively more permeable to the diluent gas than the fluorochemicals to result in a permeate stream rich in the diluent gas and a retentate rich in fluorochemicals; contacting the gas stream with one or more additional membranes which are selectively more permeable to the diluent gas than the fluorochemicals to result in a second permeate stream rich in the diluent gas and a second retentate

Abstract: An asymmetric microporous membrane with exceptional solvent resistance and highly desirable permeability is disclosed. The membrane is made by a solution-casting or solution-spinning process from a copolyamic acid comprising the condensation reaction product in a solvent of at least three reactants selected from certain diamines and dianhydrides and post-treated to imidize and in some cases cross-link the copolyamic acid. The membrane is useful as an uncoated membrane for ultrafiltration, microfiltration, and membrane contactor applications, or may be used as a support for a permselective coating to form a composite membrane useful in gas separations, reverse osmosis, nanofiltration, pervaporation, or vapor permeation.

Abstract: An efficient method removes oxidants from fluids (gases and liquids, particularly air) by means of solid phase extraction or reaction. The solid phase extraction or reaction medium comprises a porous, preferably fibrous, polymeric, membrane or web in which are incorporated oxidant scavenger particulates. Typical oxidants removed in the method include ozone, oxides of nitrogen, halogen, and peroxides. The method of the invention protects organic analytes in analytical applications and removes oxidants in remediation applications by use of oxidant scavenger particles in porous membranes.

Abstract: A hollow fiber contactor and process for fluid treatment having forced circulation with entry of fluid to be treated through the open ended lumen of a porous input hollow fiber having its opposite end closed and exit of treated fluid through the open ended lumen of an adjacent or nearby porous output hollow fiber having its opposite end closed. Fluid to be treated passes through the porous wall of an input hollow fiber, passes in contact with a treatment medium between the input and output hollow fibers forming treated fluid which passes through the porous wall of an output hollow fiber and exits the process. This invention provides high contact with treatment medium between the hollow fibers, especially suitable for selective sorption for gas purification or separation and for conduct of catalytic reactions.

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 process for purifying water including removing cations, anions and carbon dioxide and/or ammonia from water feed stream to produce high purity water having a resistivity of greater than 1 megohm-era comprising the steps of providing a water feed stream to be purified, the stream containing cations, anions and carbon dioxide and/or ammonia; introducing the water feed stream to a high pressure side of a first reverse osmosis membrane module; passing water through the first reverse osmosis membrane to provide a first retentate having cations and anions concentrated therein and a first permeate depleted in cations and anions and containing carbon dioxide and/or ammonia; adding the first permeate to a high pressure side, of a gas permeable hydrophobic membrane module; passing carbon dioxide and/or ammonia through the gas-permeable membrane from the first permeate in the high pressure side of the gas-permeable hydrophobic membrane to provide a carbon dioxide and/or ammonia permeate on a low pressure side of the h

Abstract: A filter material from active carbon compacts is prepared by the following steps:(a) mixing active carbon powder with polyvinyl alcohol powder in the ratio of 9:1 to 3:1,(b) mixing the powder from step (a) with distilled water or a mixture of distilled water and ethyl alcohol,(c) shaping tablets and similar articles in a mold under pressure, and(d) successively heating the tablets at1) 40.degree. to 80.degree. C. for 3 to 6 hours,2) 80.degree. to 120.degree. C. for 10 to 14 hours.A filter material according to the invention for the selective separation of organic material from an organic phase consists of active carbon compacts thus prepared and is used for the selective separation of organic and inorganic phases.

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: Air is compressed in an air compressor and cooled in an air cooler whereafter the impurities which have condensed out are removed. The air is subsequently reheated in a heat exchanger which is connected on the hot air side between the air compressor and the air cooler. The reheated air is passed through a plurality of membrane-type nitrogen separators, whereby the permeate of the last separator is constituted by nitrogen of the desired purity. The concentrate of this separator is recirculated to the suction side of the air compressor. The output control of the apparatus can be effected by means of an air feedback line which branches off before the heat exchanger and leads to the suction side of the air compressor. The flow through the air feedback line can be controlled by a valve which operates in dependence on the outlet pressure of the air compressor.

Abstract: Process and apparatus for the separation of at least one gas from an entering gaseous mixture (1), of the type in which a membrane separation is conducted with at least two successive membrane separators in the following manner: the entering mixture is passed through a first membrane separator (2) operating at a first operating temperature and all or a portion of the residual mixture (5) from this first membrane separator is passed through a second membrane separator (3) operating at a second operating temperature. A mixture enriched in the gas is obtained from the permeate outlet (6, 4) of each of these two separators. Two separators are used whose selectivities for the gas are different. These may be membranes of different type, or membranes of the same type, if the first operating temperature is different from the second operating temperature.

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

Abstract: A membrane-assisted process to produce ammonia is set forth wherein the recycle stream from the ammonia process containing primarily unreacted hydrogen and nitrogen but also containing inerts and unrecovered ammonia is separated in a first ammonia-selective membrane separator into a permeate stream enriched in ammonia and a non-permeate stream enriched in hydrogen, nitrogen and the inerts which is recycled to the reactor feed. A key to the present invention is that the permeate stream enriched in ammonia is recycled to the reactor effluent.

Abstract: A membrane nitrogen generator exhibiting increased flexibility and productivity in response to changes in customer demand which entails a membrane generator capable of generating nitrogen of variable flow rate and purity, bulk storage capacity for storing nitrogen of a purity which is higher than that required by a customer and flow and purity controllers for delivery to a customer plant.

Abstract: Composite membrane, process for its production and its useA composite membrane for gas separation having a three-layer structure, constructed fromA) a supporting membrane layer made of porous polymer,B) a nonporous, gas-permeable intermediate layer,C) a permselective layer of regularly arranged organic molecules having a layer thickness of 3 to 100 nm,the layers (A) and (C) enclosing the intermediate layer (B), wherein the permselective layer (C) is constructed from regularly arranged amphiphilic molecules which contain one or two alkyl chains each having 7 to 25 carbon atoms per polar hydrophilic group.

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: 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: This invention provides a composite gas separation membrane comprising: (a) a porous polyacrylonitrile structural support material having a polyacrylonitrile surface; (b) a gutter layer coating comprising a crosslinked polar phenyl-containing-organopolysiloxane material on the polyacrylonitrile surface of the structural support material, leaving an uncoated gutter layer surface; and (c) an ultrathin 6FDA type polyimide selective membrane layer coating on the uncoated gutter layer surface. In preferred embodiments, the phenyl-containing-organopolysiloxane material additionally comprises a silica-sol. Processes for making the composite gas separation membrane and for using the membrane to carry out gas separations are also provided.

Abstract: A membrane nitrogen generator adapted to deliver a flow rate of nitrogen gas having a purity at least equal to P.sub.0, which contains:a) a source of compressed nitrogen containing gas having a purity lower than P.sub.0, the source having a maximum flow rate Fm.sub.1 ;b) a varyer connected to the source, which is adapted to vary the flow rate of the source between Fm.sub.1 and 0;c) a nitrogen membrane fed by the source which is capable of delivering a low purity nitrogen gas having a purity P.sub.1, which purity is lower than P.sub.0 at the maximum flow rate Fm.sub.1 ;d) a source of high purity compressed nitrogen gas having a purity which is greater than P.sub.0 which has a controllable flow rate of from 0 to a maximum flow rate value of Fm.sub.2 ;e) a mixer; andf) a purity controller.

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.

Abstract: Aromatic polyimide membranes have superior flux at low temperature for carbon dioxide and other condensable gases. Superior flux is achieved without reduction in selectivity or other valuable properties of prior art membranes.

Abstract: .[.A process is provided for purifying argon gas, especially an argon gas stream obtained by cryogenically separating air, wherein the argon gas is heated and compressed, and then permeated through a solid electrolyte membrane selective to the permeation of oxygen over other components of the gas, and removing oxygen from the argon by selective permeation of oxygen through the membrane. The purified argon can then be distilled to remove other components such as nitrogen..]..Iadd.A process is provided for producing a purified argon stream wherein oxygen and nitrogen are removed from crude bulk argon streams, particularly those produced by cryogenic, adsorptive or membrane separation of air. The process comprises separating a heated, compressed crude argon stream containing nitrogen and oxygen into an oxygen permeate stream and an oxygen-depleted argon stream by passing the compressed heated argon stream through a solid electrolyte membrane selective to the permeation of oxygen.