(19)
(11)EP 2 954 943 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
17.06.2020 Bulletin 2020/25

(21)Application number: 15171665.1

(22)Date of filing:  11.06.2015
(51)International Patent Classification (IPC): 
B01D 53/22(2006.01)
B01D 71/02(2006.01)
B01D 69/08(2006.01)

(54)

DEVICE FOR SEPARATION OF OXYGEN AND NITROGEN

VORRICHTUNG ZUR TRENNUNG VON SAUERSTOFF UND STICKSTOFF

DISPOSITIF DE SÉPARATION D'OXYGÈNE ET D'AZOTE


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30)Priority: 11.06.2014 US 201414301945

(43)Date of publication of application:
16.12.2015 Bulletin 2015/51

(73)Proprietor: Hamilton Sundstrand Corporation
Charlotte, NC 28217 (US)

(72)Inventors:
  • RANJAN, Rajiv
    Vernon, CT 06066 (US)
  • DARDAS, Zissis A.
    Worcester, MA 01602 (US)

(74)Representative: Dehns 
St. Bride's House 10 Salisbury Square
London EC4Y 8JD
London EC4Y 8JD (GB)


(56)References cited: : 
EP-A2- 1 442 783
US-A1- 2007 022 877
US-A1- 2009 127 197
US-A- 4 230 463
US-A1- 2008 295 692
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    BACKGROUND OF THE INVENTION



    [0001] Various devices have been utilized over time for the separation of nitrogen and oxygen from air. Many such devices rely on a membrane that is exposed to pressurized air, such that oxygen molecules preferentially (compared to the larger nitrogen molecules) diffuse through the membrane, resulting in an oxygen-enriched gas on one side of the membrane and a nitrogen-rich gas on the other side of the membrane. These gases are also referred to as oxygen-enriched air (OEA) and nitrogen-enriched air (NEA), respectively. The effectiveness of membranes at performing the task of separating gases can be characterized by a trade-off that membranes experience between permeability of the membrane to the gas molecules targeted for diffusion across the membrane versus selectivity of the membrane between the targeted gas molecules and other molecules in the gas mixture. A plot of the collection of permeability versus selectivity values for various materials is known as a Robeson plot, and the upper performance limit of membrane materials is identified by a line along that plot known as the Robeson limit. Various types of materials have been used as membranes for gas separation. Inorganic metal oxides of various compositions and crystal structures have been proposed, but the materials are brittle and susceptible to damage and are also difficult to fabricate in membrane configurations. Various types of polymer and/or polymer composite materials have also been proposed. These materials can overcome some of the mechanical limitations of inorganic materials, but they typically rely on a membrane structure where selectivity is provided by a combination of the gas molecule solubility in the polymer matrix and its diffusivity through the polymer matrix, i.e. the torturous path that the gas molecules must traverse through in order to cross the membrane, and may not provide a Robeson limit that is as high as desired. Attempts to increase the selectivity of composites by incorporating high-selectivity materials into a polymer matrix have met with limited success because polymer matrices configured to prevent gas molecules from bypassing the dispersed selective material component also tend to limit the overall permeability of the membrane. Moreover, in most of the cases, these highly selective materials are incompatible with the polymer matrix, which leads to voids in the composite and reduction in selectivity.

    [0002] There are, of course, many uses for OEA or NEA, so there are a variety of applications for devices that separate oxygen and nitrogen, including but not limited to medical oxygen concentrators, atmospheric oxygen supplementation systems, and NEA-based combustion suppression systems. In recent years, commercial and other aircraft have been equipped with fuel tank suppression systems that introduce NEA into a fuel tank headspace or ullage, often by bubbling NEA through the liquid fuel. Such systems require NEA with a nitrogen concentration of at least 90 % by volume, and attempt to minimize payload weight and size while maintaining target NEA output across a wide variety of operating conditions. Nitrogen-generating using membrane technology has been used and proposed for use in these and other systems; however many of these systems suffer from various shortcomings such as performance specification limitations imposed by the membrane's Robeson limit, lack of stability in performance specifications over time, inability to maintain performance levels across a wide variety of conditions, inability to meet payload weight or size requirements, etc. Further background art is disclosed in US 2007/0022877. Accordingly, there continues to be a need for new approaches to the separation of nitrogen and oxygen.

    BRIEF DESCRIPTION OF THE INVENTION



    [0003] The method of separating oxygen from nitrogen and the device of the invention are set forth in claim 1 and claim 10 respectively.

    [0004] According to some aspects of the invention, a method of separating oxygen from nitrogen, comprises delivering air to a first side of a membrane comprising a polymer support and a layer comprising a plurality of zeolite nanosheet particles (zeolite nanosheet particles may also be referred to herein as zeolite nanosheets) with thickness of 2 nm to 10 nm and mean diameter of 50 nm to 5000 nm. It should be noted that, as used herein, "air" includes natural air from the Earth's atmosphere and also includes any gas mixture comprising nitrogen and oxygen for which the methods and materials described herein are used to separate oxygen in the gas mixture from nitrogen in the gas mixture). The delivered air provides a pressure differential between opposite sides of the membrane, thus causing oxygen to diffuse through the polymer support and the layer comprising zeolite nanosheet particles to a second side of the membrane. This preferential diffusion of oxygen (compared to the diffusion of nitrogen) through the membrane produces nitrogen-enriched air on the first side of the membrane and oxygen-enriched air on the second side of the membrane. The membrane may have a hollow core to which the air is delivered.

    [0005] According to some aspects of the invention, a device for separating nitrogen and oxygen comprises a hollow polymer fiber comprising a polymer shell surrounding a hollow core. The hollow core extends from one end of the fiber to the other end of the fiber and is open at one end of the fiber to receive a flow of air and open at the opposite end of the fiber to discharge a flow of nitrogen-enriched air. The fiber has a layer disposed on its exterior surface, comprised of a plurality of zeolite nanosheet particles with thickness of 2 nm to 10 nm and mean diameter of 50 nm to 5000 nm.

    [0006] According to some aspects of the invention, the above hollow fiber device can be prepared by disposing a hollow polymer fiber comprising a polymer shell surrounding a hollow core that extends from one end of the fiber to the other end of the fiber, in a coating composition comprising zeolite nanosheet particles with thickness of 2 nm to 10 nm and mean diameter of 50 nm to 5000 nm, such that the hollow core is isolated from the coating composition at each fiber end is connected to a source of vacuum on at least one end of the fiber. A vacuum is drawn the hollow core of the fiber to cause a pressure differential between the exterior and the hollow core of the hollow polymer fiber , which in turn causes deposition of a layer comprising zeolite nanosheet particles onto the hollow polymer fiber exterior. The zeolite nanosheet particle layer can then be heated to fuse the nanosheets together.

    BRIEF DESCRIPTION OF THE DRAWINGS



    [0007] The subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying figures, in which:

    FIG. 1 is a schematic depiction of an exemplary planar membrane for separating nitrogen and oxygen;

    FIG. 2 is a schematic depiction of an exemplary tubular membrane for separating nitrogen and oxygen; and

    FIG. 3 is a schematic depiction of an exemplary device for separating oxygen and nitrogen.


    DETAILED DESCRIPTION OF THE INVENTION



    [0008] With reference to the Figures, FIGS. 1 and 2 schematically depict exemplary membranes for separating nitrogen and oxygen. FIG. 1 depicts a flat or planar membrane 10 comprising a polymer support 12 and zeolite nanosheet layer 14. In use, air is delivered to the surface of polymer support 12 to provide a pressure differential across the membrane. In response, oxygen molecules preferentially diffuse through the membrane 10 compared to nitrogen molecules, resulting in a flow of OEA from the upper surface of the membrane 10 (e.g., through layer 14) as shown in FIG. 1, and a flow of NEA from the lower surface of membrane 10 as shown in FIG. 1.

    [0009] FIG. 2 depicts a tubular membrane 20 comprising a polymer tubular shell 22 surrounded by a zeolite nanosheet layer 24. The shell defines a hollow core 26 that is open at both ends. In use, pressurized air is delivered into the hollow core 26 at an inlet end 27 of the membrane 20. The pressure of the air is greater than air outside the core 26 such that a pressure differential between the hollow core 26 and the air exterior of the membrane 20 exists. Oxygen molecules preferentially diffuse through the tubular membrane 20 compared to nitrogen molecules, resulting in a flow of OEA from the outer surface of the tubular membrane 20 as shown in FIG. 2, and a flow of NEA from the hollow core 26 at the outlet end 28 of the membrane 20 as shown in FIG. 2.

    [0010] Turning now to FIG. 3, a device 30 comprising multiple tubular membranes 20 for separating oxygen and nitrogen is schematically depicted. As shown in FIG. 3, a device 30 for separating oxygen and nitrogen has an intake plenum 32 with inlet 34 for receiving air from an air source (not shown) such as a compressor or vehicle air intake. Air in the intake plenum flows into the hollow cores 26 (FIG. 2) of tubular membranes 20 towards discharge plenum 36, where it is collected and discharged through NEA outlet 38. Oxygen flowing through the hollow cores 26 of the tubular membranes 20 preferentially (versus nitrogen) diffuses through the tubular membranes 20, so that the gas discharged into discharge plenum 36 is nitrogen enhanced. A housing 40 is disposed around the tubular membranes 20 and forms a sealed connection with the intake plenum 32 and the discharge plenum 36. The tubular membranes 20 also form sealed connections at each end with the intake plenum 32 and discharge plenum 36, respectively, so that housing 40 together with the inner surfaces of the plenums 32, 36 forms a chamber for collecting oxygen-enhanced air, which is discharged through OEA outlet 42. It will be appreciated that, based on the guidance provided herein, one skilled in the art would set component sizes (e.g., core and outside fiber diameters), number of fibers, etc., and also to set operating parameters such as control valve settings at the inlet and the outlets to provide pressure differentials and gas flow amounts to achieve a target gas diffusion profile through the membranes.

    [0011] In some aspects of the invention, the methods and devices described herein produce a NEA stream of at least 90 vol. % nitrogen, more specifically at least 95 % nitrogen, and even more specifically at least 98 % nitrogen. In some aspects of the invention, the methods and devices described herein produce an OEA stream of at least 25 vol. % oxygen, more specifically at least 30 % oxygen, and even more specifically at least 35 % oxygen.

    [0012] The polymer supports described herein can be formed from a number of different materials, including but not limited to polyethylene, polypropylene, polytetrafluoroethylene, polycarbonate, polyethersulfone, TPU (thermoplastic polyurethane), polyimide. Thickness of the polymer support can range from 50 nm to 1000 nm, more specifically from 100 nm to 750 nm, and even more specifically from 250 nm to 500 nm. The selectivity provided by the zeolite nanosheet layer can allow for a smaller thickness compared to conventional tortorous path polymer and polymer composite membranes resulting into more permeable polymer support. In the case of tubular membranes 20 as described in FIGS. 2 and 3, fiber diameters can range from 100 nm to 2000 nm, and fiber lengths can range from 0.2 m to 2 m.

    [0013] Thickness of the zeolite nanosheet layer can range from 2 nm to 500 nm, more specifically from 2 nm to 100 nm, and even more specifically from 2 nm to 50 nm. The zeolite nanosheet particles themselves can have thicknesses ranging from 2 to 50 nm, more specifically 2 to 20 nm, and even more specifically from 2 nm to 10 nm. The mean diameter of the nanosheets can range from 50 nm to 5000 nm, more specifically from 100 nm to 2500 nm, and even more specifically from 100 nm to 1000 nm. Mean diameter of an irregularly-shaped tabular particle can be determined by calculating the diameter of a circular-shaped tabular particle having the same surface area in the x-y direction (i.e., along the tabular planar surface) as the irregularly-shaped particle. The zeolite nanosheets can be formed from any of various zeolite structures, including but not limited to framework type MFI, MWW, FER, LTA, FAU, and mixtures of the preceding with each other or with other zeolite structures. In a more specific group of exemplary embodiments, the zeolite nanosheets comprise zeolite structures selected from MFI, MWW, FER, LTA framework type. Zeolite nanosheets can be prepared using known techniques such as exfoliation of zeolite crystal structure precursors. For example, MFI and MWW zeolite nanosheets can be prepared by sonicating the layered precursors (multilamellar silicalite-1 and ITQ-1, respectively) in solvent. Prior to sonication, the zeolite layers can optionally be swollen, for example with a combination of base and surfactant, and/or melt-blending with polystyrene. The zeolite layered precursors are typically prepared using conventional techniques such as sol-gel method.

    [0014] The zeolite nanosheet layer can be formed by coating a dispersion of the nanosheets in solvent onto the polymer support using known techniques, such as spray coating, dip coating, solution casting, etc. The dispersion can contain various additives known for nanodispersions, such as dispersing aids, rheology modifiers, etc. Polymeric additives can be used; however, a polymer binder is not needed, although a polymer binder can be included and in some embodiments is included. However, a polymer binder present in an amount sufficient to form a contiguous polymer phase having the zeolite nanosheets dispersed therein can provide passageways in the membrane for nitrogen to bypass the zeolite nanosheets. Accordingly, in some embodiments a polymer binder is excluded. In other embodiments, a polymer binder is present in an amount below that needed to form a contiguous polymer phase.

    [0015] In some exemplary embodiments, the layer is applied with a vacuum enhanced dip coating process where a surface of the support is disposed in a nanosheet dispersion while a vacuum is applied from the opposite side of the support. This draws solvent from the dispersion through the polymer support, resulting in deposition of the nanosheets onto the support. In the case of hollow fiber membranes as shown in FIG. 2, this vacuum filtration technique is particularly effective, as the hollow core 26 provides an enclosed space from which to draw a vacuum without the necessity of a vacuum frame or similar structure that would be needed for a flat or planar membrane configuration.

    [0016] After coating the layer of zeolite nanosheets onto the polymer support, the layer can be dried to remove residual solvent and optionally heated to fuse the nanosheets together into a contiguous layer. Such heat should be applied under conditions to limit any heat damage to the polymer support. This can be accomplished by limiting the duration of any heating to that sufficient to heat the very thin nanosheet layer without overheating the thicker underlying polymer support. Exemplary heating conditions can involve temperatures of 20°C to 100°C, more specifically from 20°C to 75°C, and even more specifically from 20°C to 50°C.


    Claims

    1. A method of separating oxygen from nitrogen, comprising:

    coupling a source of air to a first side of a membrane (10;20) comprising a polymer support (12;22) and a layer (14;24) comprising a plurality of zeolite nanosheet particles with thickness of 2 nm to 10 nm and mean diameter of 50 nm to 5000 nm, said layer either excluding a polymer binder or, if a polymer binder is present, the polymer binder is present in an amount below that needed to form a contiguous polymer phase having the zeolite nanosheet particles dispersed therein; wherein the plurality of nanosheets are fused together;

    delivering the air such that a pressure differential between opposite sides of the membrane (10;20) exists to cause oxygen to diffuse through the polymer support (12;22) and the layer (14;24) comprising zeolite nanosheet particles to a second side of the membrane (10;20), thereby producing nitrogen-enriched air on the first side of the membrane (10;20) and oxygen-enriched air on the second side of the membrane (10;20).


     
    2. The method of claim 1, wherein said layer excludes a polymer binder.
     
    3. The method of claim 1, wherein said layer comprises a binder in an amount below that needed to form a contiguous polymer phase.
     
    4. The method of any of claims 1 to 3, wherein the zeolite nanosheet particles comprise zeolite structures selected from framework type MFI, MWW, FER, FAU, LTA and mixtures of the preceding with each other or with other zeolite structures.
     
    5. The method of any of claims 1 to 4, wherein the zeolite nanosheet particles comprise zeolite structures selected from MFI, MWW, LTA, or FER framework.
     
    6. The method of any of claims 1 to 5, wherein the layer (14;24) has a thickness of from 2 nm to 500 nm.
     
    7. The method of claim 6, wherein the layer (14;24) has a thickness of from 2 nm to 50 nm.
     
    8. The method of any of claims 1 to 7, wherein the nanosheet particles have the thickness from 2 nm to 5 nm.
     
    9. The method of any of claims 1 to 8, further comprising delivering nitrogen-enriched air from the first side of the membrane (10;20) to an aircraft fuel tank ullage space.
     
    10. A device for separating nitrogen and oxygen, comprising a membrane (10;20) comprising a polymer support (12;22) and a layer (14;24) comprising a plurality of zeolite nanosheet particles with thickness of 2 nm to 10 nm and mean diameter of 50 nm to 5000 nm, said layer either excluding a polymer binder or, if a polymer binder is present, the polymer binder is present in an amount below that which is needed to form a contiguous polymer phase having the zeolite nanosheet dispersed therein;
    wherein the plurality of nanosheets are fused together.
     
    11. The device of claim 10, wherein the membrane (20) comprises a hollow polymer fiber wherein the polymer substrate is configured as a polymer shell (22) surrounding a hollow core (26), the hollow core (26) extending from one end of the fiber to the other end of the fiber and open at one end of the fiber to receive a flow of air and open at the opposite end of the fiber to discharge a flow of nitrogen-enriched air, and the layer (24) comprising zeolite nanosheet particles is deposited on the hollow polymer fiber's exterior surface.
     
    12. The device of claim 11, comprising a plurality of said hollow polymer fibers (20) arranged in parallel between first and second plenums (32,34) such that the hollow core (26) of each fiber is in fluid communication with one of the plenums (32,34) at each end of the fiber (20), wherein the first plenum (32) is configured to deliver a flow of pressurized air into the hollow core (26) of each of the plurality of fibers (20), and the second plenum (34) is configured to receive a flow of nitrogen-enriched air from each of the plurality of fibers (20).
     
    13. The device of claim 12, further comprising a housing (40) disposed around the plurality of fibers (20), the housing (40) forming a sealed connection with each of the first and second plenums (32,34) to form a chamber for collecting oxygen-enriched air discharged through side-walls of the hollow polymer fibers (20).
     
    14. A method of making the device of claim 11, comprising disposing a hollow polymer fiber comprising a polymer shell (22) surrounding a hollow core (26) that extends from one end of the fiber to the other end of the fiber in a coating composition comprising zeolite nanosheet particles with thickness of 2 nm to 10 nm and mean diameter of 50 nm to 5000 nm, such that the hollow core (26) is isolated from the coating composition at each fiber end is connected to a source of vacuum on at least one end of the fiber;
    drawing a vacuum on the hollow core of the fiber, thereby causing a pressure differential between the exterior and the hollow core of the hollow polymer fiber, and deposition of a layer comprising zeolite nanosheet particles onto the hollow polymer fiber exterior; and heating the layer to fuse the zeolite nanosheet particles.
     


    Ansprüche

    1. Verfahren zum Trennen von Sauerstoff von Stickstoff, umfassend:

    Koppeln einer Luftquelle an eine erste Seite einer Membran (10; 20), die einen Polymerträger (12; 22) und eine Schicht (14; 24) umfasst, die eine Vielzahl von Partikeln aus zeolithischen Nanoschichten mit einer Dicke von 2 nm bis 10 nm und einem mittleren Durchmesser von 50 nm bis 5.000 nm umfasst, wobei die Schicht entweder ein Polymerbindemittel ausschließt oder, wenn ein Polymerbindemittel vorhanden ist, das Polymerbindemittel in einer Menge unter der benötigten Menge zum Bilden einer aufbauenden Polymerphase vorhanden ist, worin die Partikel aus zeolithischen Nanoschichten verteilt sind; wobei die Vielzahl von Nanoschichten miteinander verschmolzen sind;

    Zuführen der Luft derart, dass ein Druckdifferential zwischen gegenüberliegenden Seiten der Membran (10; 20) besteht, um ein Zerstreuen von Sauerstoff durch den Polymerträger (12; 22) und die Schicht (14; 24), die Partikel aus zeolithischen Nanoschichten umfasst, zu einer zweiten Seite der Membran (10; 20) herbeizuführen, wodurch mit Stickstoff angereicherte Luft auf der ersten Seite der Membran (10; 20) und mit Sauerstoff angereicherte Luft auf der zweiten Seite der Membran (10; 20) erzeugt wird.


     
    2. Verfahren nach Anspruch 1, wobei die Schicht ein Polymerbindemittel ausschließt.
     
    3. Verfahren nach Anspruch 1, wobei die Schicht ein Bindemittel in einer Menge unter der benötigten Menge zum Bilden einer aufbauenden Polymerphase umfasst.
     
    4. Verfahren nach einem der Ansprüche 1 bis 3, wobei die Partikel aus zeolithischen Nanoschichten Zeolithstrukturen umfassen, die aus einem MFI-, MWW-, FER-, FAU-, LTA-Gerüsttyp und Mischungen der vorhergehenden Typen miteinander oder mit anderen Zeolithstrukturen ausgewählt sind.
     
    5. Verfahren nach einem der Ansprüche 1 bis 4, wobei die Partikel aus zeolithischen Nanoschichten Zeolithstrukturen umfassen, die aus einem MFI-, MWW-, LTA- oder FER-Gerüst ausgewählt sind.
     
    6. Verfahren nach einem der Ansprüche 1 bis 5, wobei die Schicht (14; 24) eine Dicke von 2 nm bis 500 nm aufweist.
     
    7. Verfahren nach Anspruch 6, wobei die Schicht (14; 24) eine Dicke von 2 nm bis 50 nm aufweist.
     
    8. Verfahren nach einem der Ansprüche 1 bis 7, wobei die Partikel aus Nanoschichten die Dicke von 2 nm bis 5 nm aufweisen.
     
    9. Verfahren nach einem der Ansprüche 1 bis 8, ferner umfassend Zuführen von mit Stickstoff angereicherter Luft von der ersten Seite der Membran (10; 20) zu einem Leerraum eines Luftfahrzeugtreibstofftanks.
     
    10. Vorrichtung zum Trennen von Stickstoff und Sauerstoff, umfassend eine Membran (10; 20), die einen Polymerträger (12; 22) und eine Schicht (14; 24) umfasst, die eine Vielzahl von Partikeln aus zeolithischen Nanoschichten mit einer Dicke von 2 nm bis 10 nm und einem mittleren Durchmesser von 50 nm bis 5.000 nm umfasst, wobei die Schicht entweder ein Polymerbindemittel ausschließt oder, wenn ein Polymerbindemittel vorhanden ist, das Polymerbindemittel in einer Menge unter der benötigten Menge zum Bilden einer aufbauenden Polymerphase vorhanden ist, worin die Partikel aus zeolithischen Nanoschichten verteilt sind;
    wobei die Vielzahl von Nanoschichten miteinander verschmolzen sind.
     
    11. Vorrichtung nach Anspruch 10, wobei die Membran (20) eine hohle Polymerfaser umfasst, wobei das Polymersubstrat als eine Polymerhülle (22) konfiguriert ist, die einen hohlen Kern (26) umgibt, wobei sich der hohle Kern (26) von einem Ende der Faser zum anderen Ende der Faser erstreckt und an einem Ende der Faser zum Empfangen eines Luftstroms offen ist und am gegenüberliegenden Ende der Faser zum Auslassen eines Stroms mit Stickstoff angereicherter Luft offen ist, und wobei die Schicht (24), die Partikel aus zeolithischen Nanoschichten umfasst, an der Außenfläche der hohlen Polymerfaser abgelagert ist.
     
    12. Vorrichtung nach Anspruch 11, umfassend eine Vielzahl der hohlen Polymerfasern (20), die parallel zwischen einem ersten und zweiten Luftraum (32, 34) derart angeordnet sind, dass der hohle Kern (26) jeder Faser in Fluidverbindung mit einem der Lufträume (32, 34) an jedem Ende der Faser (20) steht, wobei der erste Luftraum (32) zum Zuführen eines Druckluftstroms in den hohlen Kern (26) von jeder der Vielzahl von Fasern (20) konfiguriert ist, und wobei der zweite Luftraum (34) zum Empfangen eines Stroms mit Stickstoff angereicherter Luft von jeder der Vielzahl von Fasern (20) konfiguriert ist.
     
    13. Vorrichtung nach Anspruch 12, ferner umfassend ein Gehäuse (40), das um die Vielzahl von Fasern (20) herum angeordnet ist, wobei das Gehäuse (40) eine abgedichtete Verbindung mit jedem des ersten und zweiten Luftraums (32, 34) bildet, um eine Kammer zum Einfangen von mit Sauerstoff angereicherter Luft, die durch Seitenwände der hohlen Polymerfasern (20) abgegeben wird, zu bilden.
     
    14. Verfahren zum Herstellen der Vorrichtung nach Anspruch 11, umfassend:

    Abgeben einer hohlen Polymerfaser, die eine Polymerhülle (22) umfasst, die einen hohlen Kern (26) umgibt, der sich von einem Ende der Faser zum anderen Ende der Faser in einer Beschichtungszusammensetzung erstreckt, die Partikel aus zeolithischen Nanoschichten mit einer Dicke von 2 nm bis 10 nm und einem mittleren Durchmesser von 50 nm bis 5.000 nm derart umfasst, dass der hohle Kern (26), der von der Beschichtungszusammensetzung isoliert ist, an jedem Faserende mit einer Vakuumquelle an mindestens einem Ende der Faser verbunden ist;

    Ziehen eines Vakuums über den hohlen Kern der Faser, dadurch Erzeugen eines Druckdifferentials zwischen dem Außenraum und dem hohlen Kern der hohlen Polymerfaser, und Ablagerung einer Schicht, die Partikel aus zeolithischen Nanoschichten umfasst, auf den Außenraum der hohlen Polymerfaser; und Erwärmen der Schicht zum Schmelzen der Partikel aus zeolithischen Nanoschichten.


     


    Revendications

    1. Procédé de séparation d'oxygène d'azote, comprenant :

    le couplage d'une source d'air à un premier côté d'une membrane (10 ; 20) comprenant un support polymère (12 ; 22) et une couche (14 ; 24) comprenant une pluralité de particules de nanofeuille de zéolite d'une épaisseur de 2 nm à 10 nm et d'un diamètre moyen de 50 nm à 5 000 nm, ladite couche excluant soit un liant polymère, soit, si un liant polymère est présent, le liant polymère est présent en une quantité inférieure à celle nécessaire pour former une phase polymère contiguë contenant les particules de nanofeuille de zéolite dispersées à l'intérieur ; dans lequel la pluralité de nanofeuilles sont fusionnées ensemble ;

    la délivrance d'air de sorte qu'un différentiel de pression entre les côtés opposés de la membrane (10 ; 20) existe pour provoquer la diffusion d'oxygène à travers le support polymère (12 ; 22) et la couche (14 ; 24) comprenant des particules de nanofeuille de zéolite sur un second côté de la membrane (10 ; 20), produisant ainsi de l'air enrichi en azote sur le premier côté de la membrane (10 ; 20) et de l'air enrichi en oxygène sur le second côté de la membrane (10 ; 20).


     
    2. Procédé selon la revendication 1, dans lequel ladite couche exclut un liant polymère.
     
    3. Procédé selon la revendication 1, dans lequel ladite couche comprend un liant en une quantité inférieure à celle nécessaire pour former une phase polymère contiguë.
     
    4. Procédé selon l'une quelconque des revendications 1 à 3, dans lequel les particules de nanofeuille de zéolite comprennent des structures de zéolite sélectionnées parmi le type d'ossature MFI, MWW, FER, FAU, LTA et des mélanges des éléments précédents les uns avec les autres ou avec d'autres structures de zéolite.
     
    5. Procédé selon l'une quelconque des revendications 1 à 4, dans lequel les particules de nanofeuille de zéolite comprennent des structures de zéolite sélectionnées parmi une ossature MFI, MWW, LTA ou FER.
     
    6. Procédé selon l'une quelconque des revendications 1 à 5, dans lequel la couche (14 ; 24) a une épaisseur de 2 nm à 500 nm.
     
    7. Procédé selon la revendication 6, dans lequel la couche (14 ; 24) a une épaisseur de 2 nm à 50 nm.
     
    8. Procédé selon l'une quelconque des revendications 1 à 7, dans lequel les particules de nanofeuille ont une épaisseur de 2 nm à 5 nm.
     
    9. Procédé selon l'une quelconque des revendications 1 à 8, comprenant en outre la délivrance d'air enrichi en azote depuis le premier côté de la membrane (10 ; 20) vers un espace vide de réservoir de carburant d'aéronef.
     
    10. Dispositif de séparation d'azote et d'oxygène, comprenant une membrane (10 ; 20) comprenant un support polymère (12 ; 22) et une couche (14 ; 24) comprenant une pluralité de particules de nanofeuille de zéolite d'une épaisseur de 2 nm à 10 nm et d'un diamètre moyen de 50 nm à 5 000 nm, ladite couche excluant soit un liant polymère, soit, si un liant polymère est présent, le liant polymère est présent en une quantité inférieure à celle nécessaire pour former une phase polymère contiguë contenant la nanofeuille de zéolite dispersée à l'intérieur ;
    dans lequel la pluralité de nanofeuilles sont fusionnées ensemble.
     
    11. Dispositif selon la revendication 10, dans lequel la membrane (20) comprend une fibre polymère creuse dans lequel le substrat polymère est configuré comme une coque en polymère (22) entourant un noyau creux (26), le noyau creux (26) s'étendant d'une extrémité de la fibre à l'autre extrémité de la fibre et étant ouvert à une extrémité de la fibre pour recevoir un flux d'air et ouvert à l'extrémité opposée de la fibre pour évacuer un flux d'air enrichi en azote, et la couche (24) comprenant des particules de nanofeuille de zéolite est déposée sur la surface extérieure de la fibre polymère creuse.
     
    12. Dispositif selon la revendication 11, comprenant une pluralité desdites fibres polymères creuses (20) agencées en parallèle entre des premier et second plénums (32, 34) de sorte que le noyau creux (26) de chaque fibre est en communication fluidique avec l'un des plénums (32, 34) à chaque extrémité de la fibre (20), dans lequel le premier plénum (32) est configuré pour délivrer un flux d'air sous pression dans le noyau creux (26) de chacune de la pluralité de fibres (20), et le second plénum (34) est configuré pour recevoir un flux d'air enrichi en azote de chacune de la pluralité de fibres (20).
     
    13. Dispositif selon la revendication 12, comprenant en outre un boîtier (40) disposé autour de la pluralité de fibres (20), le boîtier (40) formant une liaison étanche avec chacun des premier et second plénums (32, 34) pour former une chambre pour recueillir l'air enrichi en oxygène évacué à travers les parois latérales des fibres polymères creuses (20).
     
    14. Procédé de fabrication du dispositif selon la revendication 11, comprenant la disposition d'une fibre polymère creuse comprenant une coque en polymère (22) entourant un noyau creux (26) qui s'étend d'une extrémité de la fibre à l'autre extrémité de la fibre dans une composition de revêtement comprenant des particules de nanofeuille de zéolite d'une épaisseur de 2 nm à 10 nm et d'un diamètre moyen de 50 nm à 5 000 nm, de sorte que le noyau creux (26) est isolé de la composition de revêtement à chaque extrémité de fibre reliée à une source de vide sur au moins une extrémité de la fibre ;
    la création d'un vide sur le noyau creux de la fibre, provoquant ainsi un différentiel de pression entre l'extérieur et le noyau creux de la fibre polymère creuse, et le dépôt d'une couche comprenant des particules de nanofeuille de zéolite sur l'extérieur de la fibre polymère creuse ; et le chauffage de la couche pour fusionner les particules de nanofeuille de zéolite.
     




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    Cited references

    REFERENCES CITED IN THE DESCRIPTION



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    Patent documents cited in the description