Nanopore membrane and application thereof in gas separation

Abstract

The present invention relates to a process for the manufacture of nanoporous carbon membranes, membranes obtainable by this process, methods for gas separation using these membranes and the use of such membranes.

Description

Field of the Invention

[0001] The present invention relates to a method for producing nanoporous carbon membranes, membranes obtainable by this method, methods for gas separation using these membranes and uses of such membranes. Background Art

[0002] The separation of gas mixtures is becoming increasingly important for the efficient utilization of gas streams in existing processes and for the development of new resources. A particular problem is the selective separation of individual components from gas mixtures containing light hydrocarbons and / or hydrogen, and possibly other light gases such as carbon monoxide. Currently, cryogenic distillation is still commonly used to separate such gas mixtures, a process that is very energy-intensive and requires extensive equipment.

[0003] On the one hand, the energy transition requires the utilization of hydrocarbon streams, such as methane, from sources that contain significant amounts of other gaseous impurities, such as carbon dioxide or nitrogen. Utilizing biogas or natural gas from sources with a high proportion of other gases often requires purification to meet technical requirements, such as those for feeding into the gas supply network. Specific purity requirements are imposed on methane-containing gas streams for liquefaction and transport via pipelines or ships.

[0004] On the other hand, within the framework of the transition of the energy economy to a low-carbon energy system, there is a great demand for hydrogen, which should come from renewable sources, existing large-scale industrial processes or carbon-containing waste, especially plastic waste, as far as possible. Hydrogen is an efficient and clean energy carrier that produces only water as a by-product when converted into energy. It is suitable for various storage methods and is considered an important part of the development of solutions to global climate change. Currently, large-scale hydrogen production is usually achieved through steam methane reforming (SMR), coal gasification or partial oxidation of hydrocarbons. The hydrogen-rich streams obtained from these hydrogen production processes (such as synthesis gas / oxogas) contain other gas components such as CO, CO2, N2 and / or light hydrocarbons such as CH4, C2H6, C3H8, C4H 10 wait.

[0005] Steam reforming is a process that reacts carbon-containing fuels (such as natural gas, whose primary component is methane) with water vapor. The fuel is partially oxidized, producing hydrogen, as in the methane conversion process: CH₄ + H₂O → CO + 3H₂. Hydrogen production increases further if carbon monoxide (CO) is further oxidized to carbon dioxide (CO₂): CO + H₂O → CO₂ + H₂. This reaction is known as the water-gas shift reaction.

[0006] Syngas (syngas) is a gas containing hydrogen and carbon monoxide that can be used in various chemical syntheses. The traditional method for producing syngas is to gasify coal by adding water vapor and oxygen. During this process, oxygen is extracted from the water (H2O) and, together with the directly introduced oxygen, oxidizes the coal into carbon monoxide and sometimes carbon dioxide. This produces a mixture of hydrogen (H2), carbon monoxide (CO), carbon dioxide (CO2), and various impurities (such as sulfur compounds due to the sulfur content in the coal). Before further processing, the gas is typically purified to separate carbon black and metals, dried to remove unreacted water vapor, and to separate carbon dioxide and / or remove sulfur compounds. Crude oil fractions and natural gas can also be used to produce syngas. Furthermore, the conversion of carbon-containing waste, such as plastic waste (e.g., from "yellow bag" waste collection), into syngas and further into basic chemicals such as methanol has become increasingly important, as it addresses both the waste problem and the goals of a circular economy.

[0007] Gas separation and concentration using gas separation membranes offers various advantages over other methods such as distillation or high-pressure adsorption, including increased flexibility and safety, generally lower equipment requirements, and good energy efficiency. Membrane separation has long been used to separate gases due to their size and / or affinity.

[0008] It is well known that nanoporous carbon membranes can be used to separate hydrogen / hydrocarbon mixtures. M.B. Rao and S. Sircar, in Journal of Membrane Science 110 (1996), 109-118, describe the use of nanoporous carbon membranes that selectively adsorb hydrocarbons from hydrogen-containing mixtures on the high-pressure side, with the adsorbed gas molecules then diffusing through the membrane pores to the low-pressure side. To manufacture such membranes, a polyvinylidene chloride latex layer is deposited on an alumina support and carbonized in an inert atmosphere at 600°C to 1000°C. A corresponding product, called "SSF membrane" from Firma Air Products and Chemicals, proved economically unviable and never gained widespread use.

[0009] US2022 / 040644 A1 describes a membrane for purifying or separating hydrogen from a gas stream containing multiple components (such as synthesis gas). This is a multi-stage hybrid membrane comprising a sieve-like support material and two layers located thereon, both layers comprising carbon fibers, transition metal compounds, fluoropolymers and activated carbon or microporous carbon. The activated carbon used in the membrane layer has nanopores with a diameter of less than 3 nm. The pore size of each layer of the hybrid membrane is not clearly stated in the document. Therefore, US2022 / 040644 A1 does not clearly describe a membrane device for selective gas separation having an average pore size in the range of 0.3 nm to 2.0 nm and a pore size distribution in the range of 0.1 nm to 5.0 nm.

[0010] US Pat. No. 9,694,344 B2 describes a multilayer polymer film comprising an adsorbent material and a plurality of interconnected pores, as well as a single-step coextrusion method for producing the multilayer polymer film. The adsorbent material mentioned includes a carbonaceous material. The film may have up to approximately 100 layers, each of which may differ from the other in its pore structure. The average diameter of the interconnected pores generally ranges from about 0.01 nm to about 50 μm.

[0011] Known membranes do not yet have properties suitable for all separation tasks. In particular, known production methods are very complex and do not allow the properties of the membrane to be adapted to the specific separation task.

[0012] A membrane device is needed for selective gas separation, in particular for separating gas mixtures containing hydrocarbons and hydrogen. It should be possible to dispense with complex manufacturing processes, such as the layer-by-layer coating of porous support materials (e.g., alumina) followed by carbonization. The manufacturing process should allow the separation characteristics to be adapted as simply as possible to the respective separation problem. Specifically, the object of the present invention is to provide a membrane device for separating hydrocarbons, in particular C1 to C2 hydrocarbons, from hydrogen-containing gas mixtures. 14 Selective permeable membranes for hydrocarbons, especially C1 to C6 hydrocarbons, more especially C1 to C4 hydrocarbons.

[0013] It has surprisingly been found that this object can be achieved by a membrane device and a method for its production, in which a nanoporous carbonaceous layer having a well-defined pore size and pore size distribution is coated on a porous support material. Summary of the Invention

[0014] A first subject of the invention is a membrane device for selective gas separation, comprising:

[0015] a) a flat, air-permeable carrier material, and

[0016] b) a nanoporous carbon-containing layer on at least one side of the support material, wherein the nanoporous layer comprises at least one carbon component in a polymer binder, wherein the nanoporous carbon-containing layer preferably has an average pore size in the range of 0.3 nm to 2.0 nm and a pore size distribution in the range of 0.1 nm to 5.0 nm.

[0017] Another subject of the invention is a membrane device for selective gas separation, comprising:

[0018] a) Flat breathable carrier material

[0019] a / b) a microporous layer located on at least one side of the carrier material,

[0020] b) a nanoporous carbon-containing layer on the microporous layer a / b), wherein the nanoporous layer comprises at least one carbon component in a polymer binder, and the nanoporous carbon-containing layer has an average pore size in the range of 0.3 nm to 2.0 nm, and a pore size distribution in the range of 0.1 nm to 5.0 nm.

[0021] The average pore size and the pore size distribution of the nanoporous layer are determined in particular by permeation porometry.

[0022] The present invention also relates to a method for producing a membrane device, wherein:

[0023] i) providing a flat, air-permeable carrier material a),

[0024] ii) coating the support material provided in step i) with a coating agent to form a nanoporous carbon-containing layer,

[0025] The pores have an average pore size in the range of 0.3 nm to 2 nm and a pore size distribution in the range of 0.1 nm to 5.0 nm. The average pore size and the pore size distribution are determined by permeation porometry.

[0026] The present invention also relates to a method for producing a membrane device, wherein:

[0027] i) providing a flat, air-permeable carrier material a),

[0028] ii-a) coating the support material provided in step i) with a coating agent to form a microporous layer,

[0029] ii-b) coating the coated support material obtained in step ii-a) with a coating agent to form a nanoporous carbon-containing layer, wherein the pores have an average pore size in the range of 0.3 nm to 2 nm and a pore size distribution of 0.1 nm to 5.0 nm.

[0030] Preferably, step i) of the above two methods comprises:

[0031] i1) providing a fiber composition as a flat, air-permeable carrier material, the fiber composition comprising carbon fibers and / or carbon fiber precursors,

[0032] i2) subjecting the fiber composition provided in step i1) to a nonwoven fabric manufacturing process,

[0033] i3) If the fiber composition used in step i1) comprises carbon fiber precursors, subjecting the nonwoven to pyrolysis at a temperature of at least 1000° C.

[0034] A preferred embodiment is such a method:

[0035] i1) providing a fiber composition as a flat, air-permeable carrier material, the fiber composition comprising carbon fibers and / or carbon fiber precursors,

[0036] i2) subjecting the fiber composition provided in step i1) to a nonwoven fabric manufacturing process,

[0037] i3) if the fiber composition used in step i1) comprises carbon fiber precursors, subjecting the nonwoven to pyrolysis at a temperature of at least 1000° C.,

[0038] ii) coating the nonwoven fabric obtained in step i2) or i3) with a nanoporous layer.

[0039] Another subject of the present invention is a membrane device obtainable by the process as defined above and below.

[0040] Another subject of the present invention is a process for at least partially separating at least one gas component from a gas mixture, wherein the starting gas mixture is separated into at least one retentate stream and at least one permeate stream in at least one membrane separation stage, wherein the membrane separation stage comprises at least one membrane device as defined above and below or obtainable by a process as defined above and below.

[0041] Another subject of the present invention is a membrane device as defined above and below or obtainable by a process as defined above and below for use in selective gas separation, preferably for the selective separation of gas mixtures from large-scale hydrogen production, in particular for the selective separation of gas mixtures comprising hydrogen and at least one C1-C 14 Use of a gaseous mixture of hydrocarbons, preferably at least one C1-C6 hydrocarbon. DETAILED DESCRIPTION

[0042] The membrane device for selective gas separation and the method for manufacturing the membrane device by coating a nanoporous carbon-containing layer on a support material of the present invention have the following advantages:

[0043] Compared to conventional processes such as cryogenic distillation, physical or chemical absorption, and adsorption (e.g., onto activated carbon or zeolites), the membrane devices of the present invention offer advantages such as simplicity, flexibility, mobility, and a small footprint. They also typically have low investment costs and energy consumption. Furthermore, gas separation can be designed as a continuous process with only one stage.

[0044] During production, existing technologies can be used to coat a flat support material, in particular a flat fiber material, with a porous carbon-containing layer. This eliminates the need for complex, sometimes multi-stage, coating of inert, solid inorganic supports, and subsequent carbonization to adjust selectivity.

[0045] Without being bound by any theory, it is believed that the membrane devices of the present invention achieve gas separation partially or entirely through capillary condensation. Specifically, gas separation occurs through capillary condensation via a nanoporous carbonaceous layer. This transport process typically occurs in microporous membranes when gaseous components are able to condense within the membrane pores. The membrane devices of the present invention are particularly suitable for separating hydrocarbons from gas mixtures containing at least one light gas selected from hydrogen, carbon monoxide, carbon dioxide, nitrogen, and mixtures thereof. Very high selectivity can be achieved with respect to the components (typically hydrocarbons) that penetrate the membrane.

[0046] -The membrane device is characterized by its resistance to high temperature and high pressure.

[0047] Permeability is expressed as the flow rate of standard cubic meters of gas per square meter of membrane area per unit time and per unit pressure, where pressure is the difference in partial pressure between the feed / retentate and permeate of the respective gas. Perm selectivity is the ratio of the measured permeabilities of the components of the gas mixture to be separated.

[0048] Advantageously, the membrane device of the present invention has a permeability to hydrocarbons that is sufficiently great to separate hydrocarbons from a gas mixture comprising at least one light gas selected from the group consisting of hydrogen, carbon monoxide, carbon dioxide, nitrogen, and mixtures thereof.

[0049] The pore size and pore size distribution of nanoporous carbonaceous layers can be determined by permporometry. The principle of permporometry is to control the gradual blockage of pores by capillary condensation of condensable components in a gas mixture while simultaneously measuring the gas flow through the membrane. This principle is described, for example, by F.C. Cuperus et al. in J. Membrane Sci 71 (1992), 57-67. Commercial equipment is available from APTCO TECHNOLOGIES NV, Belgium. Olga Solcova et al. describe the application of permeation porometry to porous materials with large thickness and wide pore size distribution in Liquid Expulsion Permporometry-a Tool for Obtaining the Distribution of Flow-Through Pores, Part. Part. Syst. Charact. 23 (2006) 1-8, DOI: 10.1002 / ppsc.200601014.

[0050] The average pore size of the nanoporous carbon-containing layer is in the range of 0.3 nm to 2.0 nm, preferably 0.4 nm to 1.5 nm, and particularly preferably 0.5 nm to 1.3 nm (determined by permeation porometry).

[0051] The pore size distribution range of the nanoporous carbon-containing layer is 0.1 nm to 5.0 nm (measured by a permeation pore measurement method).

[0052] The layer thickness of the nanoporous carbon-containing layer is preferably in the range of 0.5 μm to 500 μm, particularly preferably in the range of 1.0 μm to 10 μm.

[0053] The porosity of the nanoporous carbon-containing layer is preferably in the range of 20% to 80%, particularly preferably 60% to 70%, which is determined by the ratio of the pore volume fraction to the total volume of the nanoporous carbon-containing layer. The pore volume fraction can be determined by permeameter porosimetry.

[0054] Planar carrier material a)

[0055] The membrane device according to the invention for selective gas separation comprises at least one planar, gas-permeable carrier material a).

[0056] The planar, air-permeable carrier material a) is preferably selected from the group consisting of fibrous materials, porous metal carriers, porous ceramic and non-ceramic carriers, monolithic carriers, air-permeable polymer carriers and combinations thereof.

[0057] Suitable fiber materials include organic fibers, inorganic fibers, and combinations thereof. Preferred fiber materials include synthetic polymer fibers, natural polymer fibers, carbon fibers, metal fibers, ceramic fibers, glass fibers, basalt fibers, silicate fibers, mineral fibers, and combinations thereof.

[0058] In a preferred embodiment, the carrier material a) comprises at least one planar fiber material or consists of at least one planar fiber material, wherein the carrier material is preferably selected from the group consisting of nonwovens, braids, knits, paper and combinations thereof.

[0059] Within the context of the present invention, a fiber web generally refers to a planar structure consisting primarily of individual fibers, whose cohesion is essentially provided solely by the inherent adhesive forces of the individual fibers. Fiber web bonding processes are generally classified as mechanical, chemical, or thermal, and are used to transform a fiber web into a nonwoven fabric by creating stronger bonds between the fibers than are present in the fiber web. Fiber webs, nonwoven fabrics, and methods for their production are described in H. Fuchs and W. Albrecht, "Nonwovens," 2nd edition (Wiley-VCH, Weinheim, Germany).

[0060] Suitable porous metal supports are, for example, porous metals (such as aluminum) or metal fabrics.

[0061] Suitable inorganic supports include porous ceramic and non-ceramic supports. Suitable support materials include clay minerals, aluminum oxide, silicon oxide, aluminum silicate, in particular zeolites, zirconium dioxide, titanium dioxide, yttrium oxide, other metal oxides, glass, silicon nitride, silicon carbide, Si-CO, Si-CNO, Si-BNC, etc. and combinations thereof.

[0062] In addition, monolithic supports are also suitable supports. Such supports and methods for their preparation are known to those skilled in the art.

[0063] Suitable supports are also gas-permeable polymer supports, for example polymers selected from the group consisting of polyamides, polyimides, polypyrrolones, polyesters, polysulfones, polymeric organosilicon compounds, fluoropolymers, polyolefins and copolymers and mixtures (blends) thereof.

[0064] In principle, the membrane device and / or carrier material a) can have any shape suitable for the intended application. For example, the base surface of the membrane device and / or carrier material can be polygonal (n-gon with n ≥ 3, such as a triangle, quadrilateral, pentagon, hexagon, etc.), circular, circle segment (such as a semicircle), elliptical, or elliptical segment. The base surface is preferably rectangular or circular. For example, the membrane device can be designed as a substantially flat disk (plate), tubular, honeycomb, or polygonal prism. Furthermore, the membrane device can have a support device or be self-supporting.

[0065] The support material can be composed of one or more layers, for example 2 layers, 3 layers, 4 layers, 5 layers or more. Each layer can be composed of different support materials or the same support material, and these support materials are different from each other in composition and / or another physicochemical property (such as porosity or pore size distribution). Each layer can also be designed as a composite material. Such a composite material can, for example, have at least one porous substrate and at least one porous or non-porous support material (such as a fiber material or a polymer support) and, if necessary, at least one binder. Suitable porous substrates include, for example, porous metals, porous ceramics and non-ceramic materials, porous glass, etc.

[0066] The support material may have an asymmetric, in particular gradient-like, layer structure. For example, the nanoporous carbon-containing layer b) may be arranged on a support material consisting of at least two layers with different porosities. For example, in a gradient-like layer structure, the porosity may decrease continuously towards the nanoporous carbon-containing layer.

[0067] The support material may optionally have at least one inorganic layer. The inorganic layer may, for example, be disposed between the nanoporous carbonaceous layer b) and at least one other support layer. The inorganic layer may, for example, comprise a large number of discrete particles. The particle size of these particles is preferably a maximum of 1 micron, in particular a maximum of 500 nm. The particles in the inorganic layer are, for example, selected from alkaline earth metal oxide particles, transition metal oxide particles, lanthanide metal oxide particles, fourth main (IVA) group metal oxide particles, transition metal particles, metal alloy particles, silicate particles, aluminosilicate particles, zeolite particles, clay mineral particles, and combinations thereof. Particle size analysis can be performed by laser diffraction according to ISO 13320:2020-01.

[0068] The membrane device of the present invention preferably includes at least one planar fiber material as component a). In particular, component a) includes a fiber material selected from nonwovens, woven fabrics, knitted fabrics, paper, and combinations thereof. Fibers suitable for fiber material a) include carbon fibers, glass fibers, organic polymer (e.g., polyolefin, polyester, polyamide) fibers, and mixtures thereof in principle. The fibers contained in fiber material a) preferably include carbon fibers or consist of carbon fibers. Such fiber materials are particularly advantageous in meeting requirements such as gas diffusivity and thermal conductivity. Carrier material a) is preferably selected from carbon fiber woven fabrics, carbon fiber paper, and carbon fiber nonwovens. In a particularly preferred embodiment, carrier material a) includes at least one carbon fiber nonwoven, or carrier material a) consists of a carbon fiber nonwoven.

[0069] The production of carbon fibers can be carried out in a conventional manner, with polyacrylonitrile fibers (PAN fibers) preferably being used as starting material.

[0070] In carbon fiber braids, the planar fiber material is formed by interlacing two thread systems: warp (warp yarn) and weft (filling yarn). As in textiles, the fiber bundles are flexible but inseparably connected. Carbon fiber braids are preferably made from oxidized, but not yet carbonized or graphitized, PAN fibers. Carbonization or graphitization is performed after braiding to impart electrical conductivity to the planar fiber material.

[0071] Oxidized PAN fibers are preferably used to produce carbon fiber paper. These fibers are comminuted into fiber fragments in a known manner, then pulped and, like papermaking, sieved (in pulpwood troughs) to form a fiber web and dried. In a preferred embodiment, at least one binder is further introduced into the paper. Suitable binders include, for example, phenolic resins, furan resins, polyimide resins, and the like. When introducing the binder, the paper can first be impregnated with the binder and then cured as needed. After impregnation and curing, the carbon fiber paper is again carbonized / graphitized to convert the binder into a more conductive compound. In another suitable embodiment, filled carbon fiber paper is used to provide the carrier material a). The initial manufacturing steps are as described above, but instead of introducing a binder and carbonizing / graphitizing, a filler consisting of a carbon material in a polymer binder is introduced into the still-damp paper. Specifically, a carbon-PTFE filler is used. This filling can improve thermal and electrical conductivity, thereby eliminating the need for carbonization / graphitization.

[0072] Carbon fiber nonwovens can be produced using non-oxidized or oxidized PAN fibers. In a first preferred embodiment, the first step is to fluff (card) the fibers and then bond them to form a nonwoven. This can be achieved, for example, by hydroentangling, in which the carbon fibers are oriented, entangled, and thus mechanically stabilized. If necessary, the thickness of the bonded nonwoven can be calibrated to the desired value. Nonwovens based on non-oxidized PAN fibers are first oxidized at elevated temperatures in an oxygen atmosphere after web formation and bonding, and then carbonized / graphitized in an inert gas atmosphere. Nonwovens based on oxidized PAN fibers are only carbonized / graphitized after web formation and bonding.

[0073] In a first specific embodiment, a mechanically bonded fiber material is used as the carrier material a). In another specific embodiment, a nonwoven fabric into which at least one binder has been incorporated is used as the fiber material a). The binder is then optionally cured. Suitable binders include, for example, phenolic resins, furan resins, polyimide resins, and the like.

[0074] In a specific embodiment, a non-woven fabric is used as the carrier material a), into which at least one fluorine-free, high-temperature-resistant polymer is introduced as a fiber material and / or binder. In this case, the fluorine-free, high-temperature-resistant polymer is selected from polyaryletherketone, polyphenylene sulfide, polysulfone, polyethersulfone, partially arylated (co)polyamide, polyimide, polyamideimide, polyetherimide and mixtures thereof. The fluorine-free, high-temperature-resistant polymer can be used as a component of the fiber material to supplement or replace at least one carbon fiber material. The fluorine-free, high-temperature-resistant polymer can also be used as a binder. For example, the binder can be introduced after carbonization / graphitization, and the resulting impregnated non-woven fabric is finally subjected to a heat treatment (intended for drying and / or sintering) again.

[0075] The planar carrier material a) is preferably a fiber composite material comprising a fiber material which is preferably selected from the group consisting of carbon fiber nonwovens, carbon fiber braids and mixtures thereof.

[0076] In particular, the fiber composite material comprises at least one fiber material and at least one polymer additive a1) applied thereto and / or incorporated therein and, if appropriate, at least one further additive a2).

[0077] The polymer additive a1) is preferably selected from fluorine-containing polymers a11), fluorine-free high-temperature-resistant polymers a12), polymers different therefrom a13), and mixtures thereof.

[0078] The polymer additive a1) preferably accounts for 0.5% to 50% by mass, preferably 1% to 40% by mass, based on the mass of the fiber material used as carrier material a).

[0079] In a specific embodiment, the polymer additive a1) includes at least one fluoropolymer a11). In this case, the mass proportion of the fluoropolymer a11) is preferably 0.5% to 40%, preferably 1% to 30%, based on the mass of the fiber material used as the carrier material a). By adding at least one fluoropolymer a11), the hydrophobicity of the fiber material used as the carrier material a) can be increased. This can have a favorable effect on the transport process in the membrane device. In principle, the fluoropolymer b1) used as the polymer binder for the nanoporous layer is suitable as the fluoropolymer a11). The fluoropolymer a11) is preferably selected from polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), perfluoroalkoxy polymer (PFA) and mixtures thereof. Perfluoroalkoxy polymers are, for example, copolymers of tetrafluoroethylene (TFE) and perfluoroalkoxy vinyl ether (such as perfluorovinyl propyl ether). Polytetrafluoroethylene is preferably used as the polymer a11). Conventional impregnation processes can be used to finish the fiber material with the fluoropolymer a11). For this purpose, for example, a PTFE dispersion can be applied in an immersion bath, the solvent evaporated, and the treated fiber material sintered at elevated temperature (generally at least 300° C.).

[0080] In another specific embodiment, the polymer additive a1) includes at least one fluorine-free, high-temperature-resistant polymer a12). In this case, the fluorine-free, high-temperature-resistant polymer a12) is preferably selected from polyaryletherketones, polyphenylene sulfides, polysulfones, polyethersulfones, partially arylated (co)polyamides, polyimides, polyamideimides, polyetherimides, and mixtures thereof. In this case, the weight of the fluorine-free, high-temperature-resistant polymer a12) is preferably 0.5% to 40%, preferably 1% to 30%, based on the weight of the fiber material used as carrier material a).

[0081] In a particular embodiment, the polymer additive a1) comprises a mixture of at least one fluorine-containing polymer a11) and at least one fluorine-free, high-temperature-resistant polymer a12). In this case, the total weight of the polymers a11) and a12) is preferably 0.5% to 40%, preferably 1% to 30%, based on the weight of the fiber material used as the carrier material a).

[0082] The polymer additive a1) may include at least one other polymer a13) different from a11) and a12). Suitable polymers a13) are, for example, selected from phenolic resins, furan resins, polyimide resins, and mixtures thereof. Specifically, the polymer additive a1) comprises a polymer a13) different from the fluoropolymer a11) and the polymer a12) in a manner applied thereto and / or introduced therein, and the weight proportion of the other polymer is up to 5%, preferably up to 1%, particularly preferably up to 0.5%, and in particular up to 0.1%, based on the total weight of the fiber material A). More specifically, no other polymer a13) different from the fluoropolymer a11) and the polymer a12) is added to the fiber material a).

[0083] The fiber material serving as carrier material a) may also contain at least one additive a2). Suitable additives include fillers and reinforcing materials, surface-active compounds, tackifiers, and the like. The additive a2) is preferably selected from metal particles, carbon black, graphite, graphene, carbon nanotubes (CNTs), carbon nanofibers, and mixtures thereof. Graphitic carbon nanofibers (GCNFs) are a specific embodiment of carbon nanofibers. Particularly preferably, the additive a2) comprises or consists of carbon black. For example, the fiber material a) may be finished simultaneously with at least one additive a2) and a polymer additive a1).

[0084] The weight percentage of the additive a2) is preferably 0% to 80%, particularly preferably 0% to 50%, based on the weight of the fiber material used as carrier material a). In a specific embodiment, the additive a2) comprises or consists of carbon black. In this case, the weight percentage is preferably 0.5% to 45%, particularly preferably 1% to 25%, based on the weight of the fiber material used as carrier material a).

[0085] The thickness of the fiber material a) is preferably in the range of 50 μm to 500 μm, particularly preferably 100 μm to 400 μm. This thickness refers to the thickness of the fiber material a) in the unfinished and uncompressed state (ie, before being placed in the membrane device).

[0086] The fiber material used as carrier material a) can be finished with components a1) and / or a2) by conventional processes. Preferably, the fiber material is finished with an aqueous dispersion. Suitable coating and impregnation methods are described in detail below.

[0087] In certain embodiments, the fiber material treated with components a1) and / or a2) is subjected to a heat treatment (drying and / or sintering). The heat treatment of the fiber material is preferably carried out at a temperature of at least 250° C., particularly preferably at least 300° C., and in particular at a temperature in the range of 300° C. to 450° C. The heat treatment can also be carried out after the nanoporous carbon-containing layer b) has been applied, as described in detail below.

[0088] Nanoporous carbon-containing layer b)

[0089] The membrane arrangement of the invention comprises a two- or multi-layered layer composite based on a flat, gas-permeable carrier material a) and a nanoporous, carbon-containing layer b) situated on at least one side of the carrier material a).

[0090] Specifically, the nanoporous layer b) comprises at least one carbon component in a polymer binder. At least one additive may also be used when producing the nanoporous layer. Suitable additives are, for example, pore formers.

[0091] The carbon component is preferably selected from carbon black, graphite, graphene, carbon nanotubes (CNTs), carbon nanofibers, in particular graphitic carbon nanofibers (GCNFs), carbon-containing products during the production of the nanoporous carbon-containing layer b), and mixtures thereof. Preference is given to using carbon black, graphite, or mixtures thereof.

[0092] In particular, the polymer binder comprises at least one fluoropolymer b1), which is preferably selected from polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymers, perfluoroalkoxy polymers and mixtures thereof. Polytetrafluoroethylene is preferably used as polymer b1).

[0093] Alternatively or additionally, the polymer binder comprises at least one high-temperature polymer b2), which is preferably selected from polyaryletherketones, polyphenylene sulfides, polysulfones, polyethersulfones, partially arylated (co)polyamides, polyimides, polyamideimides, polyetherimides and mixtures thereof.

[0094] In a particular embodiment, the polymer binder comprises at least one polymer b1) and at least one polymer b2), wherein b1) comprises or consists of polytetrafluoroethylene (PTFE) and b2) comprises or consists of polyetheretherketone (PEEK).

[0095] The polymer b2) is preferably selected from so-called high-performance plastics, which are characterized by a high glass transition temperature, a high melting point, good temperature and chemical resistance, and good mechanical properties. The polymer b2) preferably has a continuous operating temperature (continuous use temperature) of at least 150° C. Specifically, the polymer b2) is a thermoplastic.

[0096] Preferred polymers b2) are partially arylated polymers and aromatic polymers.

[0097] The polymer b2) is preferably selected from polyaryletherketone (PAEK), polyphenylene sulfide (PPS), polysulfone (PSU), polyethersulfone (PES), partially aromatic (co)polyamides (high temperature polyamides, HTPA), polyimides (PI), polyamideimides (PAI), polyetherimides (PEI) and mixtures (blends) thereof.

[0098] Suitable polymers b2) are also (partially) aromatic polyesters, such as PET or PBT, polycarbonate (PC) and temperature-resistant melamines, such as nanoporous SiO 2 aerogel-filled melamine foams.

[0099] In a preferred embodiment, the polymer component b2) comprises at least one polyaryletherketone. In particular, the polymer component b2) consists of at least one polyaryletherketone. Polyaryletherketone (PAEK) is a partially crystalline thermoplastic with an alternating structure in which an aromatic group is followed by a keto (carbonyl) or ether group, wherein the proportion of keto and ether groups is variable and the substitution pattern on the aromatic ring may also vary. Suitable polyaryletherketones b2) include polyetherketone (PEK), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), etc. Preferably, the polymer component b2) comprises at least one polyetheretherketone or consists of at least one polyetheretherketone.

[0100] Suitable partially aromatic (co)polyamides b2) are polymers known as high-temperature polyamides (HTPA). These are partially crystalline or amorphous thermoplastic partially aromatic polyamides. They preferably polymerically contain at least one aromatic dicarboxylic acid, in particular selected from terephthalic acid, isophthalic acid, and mixtures of terephthalic acid and isophthalic acid. Preferred partially aromatic (co)polyamides b2) are selected from PA 6.T, PA 10.T, PA 12.T, PA 6.1, PA 10.1, PA 12.1, PA 6.T / 6.1, PA 6.T / 6, PA 6.T / 10T, PA 10.T / 6.T, PA 6.T / 12.T, PA 12.T / 6.T, and mixtures thereof. Polyphthalamide (PPA) is another specific embodiment of polyamide b2).

[0101] Polysuccinimide (PSI), polybismaleimide (PBMI), polyimide sulfone (PISO) and polymethacrylimide (PMI) are suitable polyimides b2).

[0102] In particular, the polymer binder comprises at least one fluorine-free, high-temperature-resistant polymer b2) and at least one different fluorine-containing polymer b1). Preferably, at least one polyetheretherketone is used as polymer b2) and polytetrafluoroethylene is used as polymer b1).

[0103] The nanoporous layer b) is preferably produced using a polymer binder in an amount of 0.5 to 50% by weight, particularly preferably 1.0 to 40% by weight, in particular 10 to 25% by weight, based on the total weight of the polymer binder and the carbon component.

[0104] The nanoporous carbon-containing layer of the present invention has a favorable pore structure. Studies have found that by using the polymer binder described as component b2) above, a certain proportion of larger pores can be generated in the nanoporous layer. The choice of filler and reinforcement material can also affect the pore size and pore size distribution. For example, the use of graphite (particularly coarse-grained graphite or expanded graphite) generally produces larger pores than the use of carbon black. In addition, the use of pore-forming agents can also affect the total pore volume, the number of pores and their pore size distribution. For example, suitable pore-forming agents are commercially available plastic particles, such as plastic particles made of polymethyl methacrylate (PMMA).

[0105] Preferably, the thickness of the nanoporous layer in an uncompressed state is 5 to 100 microns, preferably 10 to 50 microns. This thickness refers to the thickness of the nanoporous layer b) in an uncompressed state (ie, before being installed in the composite gas separation device).

[0106] The thickness of the membrane device of the present invention (total thickness of the support material a) and the nanoporous layer b) is preferably in the range of 50 μm to 1000 μm, particularly preferably in the range of 75 μm to 500 μm. This thickness refers to the thickness of the membrane device in the uncompressed state (i.e., before installation in the composite gas separation device).

[0107] The thickness of the flat, air-permeable carrier material a), the nanoporous carbonaceous layer b) and the membrane arrangement can be determined in accordance with DIN 53855-1:1993-08 “Determination of thickness of textile fabrics”.

[0108] In g / m 2 The determination of mass per unit area (also known as grammage) can be carried out according to EN 29073-1:1992.

[0109] Microporous layer a / b)

[0110] In a particular embodiment, the membrane device of the invention comprises a three-layer or multi-layered composite based on a planar, gas-permeable carrier material a), a microporous layer a / b) on at least one side of the carrier material a), and a nanocarbon-containing layer b) on the microporous layer a / b).

[0111] Specifically, the microporous layers a / b) comprise conductive particles in a matrix formed by a polymer binder. The conductive particles are preferably selected from conductive carbon particles, in particular carbon black, graphite, graphene, carbon nanotubes (CNTs), carbon nanofibers and mixtures thereof. Preference is given to using carbon black, graphite or mixtures thereof.

[0112] The polymer binder of the microporous layers a / b) preferably comprises at least one polymer selected from the group consisting of fluorine-containing polymers, fluorine-free high-temperature polymers, polymers different therefrom, and mixtures thereof.

[0113] In particular, the polymer binder of the microporous layers a / b) comprises at least one fluoropolymer. Suitable fluoropolymers are the fluoropolymers b1) described above for forming the nanoporous layer b), the relevant contents of which are incorporated herein in their entirety. In particular, the polymer binder of the microporous layers a / b) comprises at least one fluoropolymer b1), which is preferably selected from polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymers, perfluoroalkoxy polymers, and mixtures thereof. Polytetrafluoroethylene is preferably used as the polymer binder of the microporous layers a / b).

[0114] Alternatively or in addition, the polymer binder of the microporous layers a / b) comprises at least one fluorine-free, high-temperature-resistant polymer. Suitable fluorine-free, high-temperature-resistant polymers are the polymers b2) described above for forming the nanoporous layer b), the relevant contents of which are incorporated herein in their entirety. In particular, the polymer binder of the microporous layers a / b) comprises at least one fluorine-containing polymer b2), preferably selected from the group consisting of polyaryletherketones, polyphenylene sulfides, polysulfones, polyethersulfones, partially arylated (co)polyamides, polyimides, polyamideimides, polyetherimides, and mixtures thereof.

[0115] In a particular embodiment, the polymer binder of the microporous layers a / b) comprises at least one polymer b1) and at least one polymer b2), wherein b1) comprises or consists of polytetrafluoroethylene (PTFE) and b2) comprises or consists of polyetheretherketone (PEEK).

[0116] The microporous layer a / b) is preferably produced using a polymer binder, the weight proportion of which is 0.5 wt % to 50 wt %, particularly preferably 1.0 wt % to 40 wt %, especially 10 wt % to 25 wt %, based on the total weight of the polymer binder and the conductive particles.

[0117] The microporous layers a / b) can be applied to the carrier material a) using various methods. Spraying, screen printing, or wire-bar coating processes are typically used for discontinuous production, while doctor blade, slot nozzle, and engraved roller processes are preferred for continuous coating. Finally, a thermal treatment can be performed, for example in a drying and sintering furnace. Drying can initially be performed at temperatures between 100°C and 200°C, followed by sintering at temperatures between 300°C and 500°C, if necessary.

[0118] Unlike the macroporous fiber material a) and the nanoporous layer b), MPLa / b) is microporous. The average pore diameter of the microporous layer a / b) is preferably in the range of 5 nm to 10 μm, particularly preferably in the range of 7 nm to 1 μm, and in particular in the range of 10 nm to 900 nm.

[0119] The porosity and pore size distribution of the microporous layer a / b) can be determined using mercury intrusion porosimetry, as described in DIN ISO 15901-1:2019-03 and ISO 15901-1:2016 - Part 1: Mercury intrusion porosimetry.

[0120] In a particular embodiment, the microporous layers a / b) contain no added transition metal compounds.

[0121] In a particular embodiment, the microporous layers a / b) contain no added fibers, in particular no added carbon fibers.

[0122] The thickness of the microporous layer a / b) is preferably in the range of 5 μm to 150 μm, particularly preferably 10 μm to 100 μm. This thickness refers to the thickness of the microporous layer a / b) in the uncompressed state (ie before being incorporated into the membrane device).

[0123] Manufacturing method

[0124] Another subject of the invention is a method for producing a membrane device, wherein

[0125] i) providing a flat, air-permeable carrier material a),

[0126] ii) coating the support material provided in step i) with a coating agent to form a nanoporous carbon-containing layer, wherein the pores have an average pore diameter in the range of 0.3 nm to 2 nm and a pore size distribution of 0.1 nm to 5.0 nm, both preferably determined by permeometric porometry.

[0127] Another subject of the invention is a method for producing a membrane device, wherein

[0128] i) providing a flat, air-permeable carrier material a),

[0129] ii-a) coating the support material provided in step i) with a coating agent to form a microporous layer,

[0130] ii-b) coating the coated support material obtained in step ii-a) with a coating agent to form a nanoporous carbon-containing layer, wherein the pores have an average pore size in the range of 0.3 nm to 2 nm and a pore size distribution of 0.1 nm to 5.0 nm.

[0131] The planar, breathable carrier material a) provided in step i) of the above-described method may have one or more layers. In this respect, reference is made to the above description of suitable carrier materials. In a preferred embodiment, the carrier material a) comprises at least one planar fiber material. In a specific embodiment, even if the carrier material a) has a multilayer structure, the nanoporous carbon-containing layer b) is applied to the planar fiber material. The planar fiber material is preferably selected from non-woven fabrics, woven fabrics, knitted fabrics, paper and combinations thereof. For suitable and preferred fiber materials, please refer to the above description in full. Before being applied to step ii), the fiber material can be finished with conventional adhesives and / or additives, as has also been described above. For this purpose, conventional impregnation processes can be used. Before being applied to step ii), the fiber material, which has been finished as needed, can be subjected to a heat treatment (drying and / or sintering).

[0132] Optionally, in step a / b), the carrier material a) provided in step i) (in particular a fibrous material) can be coated with a coating agent to form a microporous layer. Possible methods for applying the microporous layer a / b) to the carrier material a) have been described above.

[0133] In a first embodiment, in step ii), the support material a) (particularly a fibrous material) provided in step i) is coated with a coating agent to form the nanoporous layer b). The support material is preferably coated and / or impregnated with an aqueous composition comprising at least one carbon component, a polymer binder, and optionally other additives. All components used to form the nanoporous layer can be used in a single composition used to coat the support material a). The support material a) can also be coated with two or more coating agents, each comprising one or more components. For suitable and preferred polymers b1) and b2), reference is made to the description above.

[0134] In a second embodiment, the support material a) (in particular a fibrous material) provided in step i) is coated with a coating agent in step ii-a) to form a microporous layer and then coated with a coating agent in step ii-b) to form a nanoporous layer b).

[0135] The nanoporous layer can be applied in step ii) or step ii-b) using various methods. Spraying, screen printing, or wire-bar coating processes are typically used for discontinuous production, while doctor blade, slot nozzle, and engraved roller processes are preferred for continuous coating. The thickness of the nanoporous layer and the penetration depth of the coating agent into the support material are influenced by the coating process parameters and the viscosity of the coating agent.

[0136] Finally, heat treatment can be performed, for example, in a drying and sintering furnace. For example, drying can be performed at a temperature of 100° C. to 200° C., followed by sintering at a temperature of 300° C. to 500° C. The heat treatment in step ii) is preferably performed at a temperature that partially or completely melts the polymer binder.

[0137] A preferred embodiment is such a method:

[0138] i1) providing a fiber composition as a flat, air-permeable carrier material, the fiber composition comprising carbon fibers and / or carbon fiber precursors,

[0139] i2) subjecting the fiber composition provided in step i1) to a nonwoven fabric manufacturing process,

[0140] i3) if the fiber composition used in step i1) comprises carbon fiber precursors, subjecting the nonwoven to pyrolysis at a temperature of at least 1000° C.,

[0141] ii) coating the nonwoven fabric obtained in step i2) or i3) with a nanoporous layer.

[0142] Separation of gas mixtures

[0143] During separation, the starting gas mixture can be passed through one or more membrane devices. Multiple membrane devices can be arranged in series or in parallel, depending on the direction of gas flow. Combinations of series and parallel membrane devices are also possible. Furthermore, the gas flow can be partially or fully returned to an upstream membrane device to form a recirculation loop. The series connection of two or more membrane devices is preferred for improving selectivity. Parallel connection is preferred for increasing throughput, facilitating maintenance, and / or allowing for replacement of membrane devices during operation.

[0144] The membrane device for gas separation comprises a device for supplying a starting gas mixture and a device for discharging at least one gas stream obtained in the gas separation process.

[0145] Another subject of the invention is a membrane device as defined above or obtainable by a method as defined above. In this context, the term membrane device also includes devices for gas separation consisting of two or more individual membrane devices.

[0146] Another subject of the present invention is a process for at least partially separating at least one gas component from a gas mixture, wherein the starting gas mixture is separated into at least one retentate stream and at least one permeate stream in at least one membrane separation stage, wherein the membrane separation stage comprises at least one membrane device as defined above or obtainable by a process as defined above.

[0147] Another subject of the present invention is a membrane device as defined above or obtainable by a process as defined above for use in selective gas separation, preferably for the selective separation of gas mixtures from large-scale hydrogen production, in particular for the selective separation of gas mixtures comprising hydrogen and at least one C1-C 14 Use of a gaseous mixture of hydrocarbons, preferably at least one C1-C6 hydrocarbon.

[0148] The following examples are intended to illustrate the present invention but are not intended to limit the scope of the present invention.

[0149] Example 1:

[0150] Manufacturing membrane devices using carbon fiber nonwoven fabrics as carrier materials and nanoporous carbon-containing layers

[0151] To produce the base nonwoven, a dry-laid fiber fleece made of 100% oxidized polyacrylonitrile fibers is laid on a carding device. The fiber fleece is fed into a bonding unit, where the fibers are intertwined on both sides by high-energy water jets. The pressure in the first stage is approximately 100 bar, and the pressure in the second stage is approximately 200 bar. The nonwoven is then calibrated to a thickness of 0.25 mm for the hydroentangled nonwoven. The nonwoven is then fed into a carbonization unit, where it is carbonized at a temperature of approximately 1000°C to 1400°C under a nitrogen atmosphere. The resulting nonwoven consists of 100% carbon fibers and has a grammage of 65 g / m². 2 For finishing of the nonwoven fabric, an aqueous impregnation composition was mixed, which, based on solid matter, contained 70% carbon black and 30% polytetrafluoroethylene (PTFE). The finishing method was padding with the aqueous dispersion, with the impregnation weight accounting for 15% of the mass of the nonwoven substrate (equivalent to 10 g / m 2 ). It was then dried at 160°C for 5 minutes and sintered at 400°C for 10 minutes. Next, a coating was applied to the substrate obtained in this way to form a planar nanoporous layer. The composition of the coating agent for forming the nanoporous layer was 2% PTFE, 2% PEEK, 0.11% surfactant additive and 11% nanoporous carbon. The fiber material was then dried at 160°C and sintered at 400°C. The final loading of the nanoporous layer was 35 g / m 2 .

[0152] Table 1 lists the permeabilities and selectivities achieved for the materials in Example 1.

[0153] Table 1

[0154] Air hydrogen butane <![CDATA[C4H 10 / H2 Selectivity]]> <![CDATA[Pure gas permeability [L / m 2 ·s·Pa]]]> 3.185E-09 9.1E-09 9.3E-09 1.0 <![CDATA[Mixed gas permeability [L / m 2 ·s·Pa]]]> 6.0E-11 6.6E-09 110.0

[0155] Example 2:

[0156] Production of membrane devices using carbon fiber nonwovens as carrier materials and microporous and nanoporous carbon-containing layers

[0157] To produce the basic nonwoven, a dry-laid fiber fleece made of 100% oxidized polyacrylonitrile fibers is laid on a carding device. The fiber fleece is fed into a bonding unit, where the fibers are intertwined on both sides by high-energy water jets. The pressure in the first stage is approximately 100 bar, and the pressure in the second stage is approximately 200 bar. The nonwoven is then calibrated to a thickness of 0.25 mm for the hydroentangled nonwoven. The nonwoven is then fed into a carbonization unit, where it is carbonized at a temperature of approximately 1000°C to 1400°C under a nitrogen atmosphere. The resulting nonwoven consists of 100% carbon fibers and has a grammage of 65 g / m2. 2 For finishing of the nonwoven fabric, an aqueous impregnation composition was mixed, which, based on solid matter, contained 70% carbon black and 30% polytetrafluoroethylene (PTFE). The finishing method was padding with the aqueous dispersion, with the impregnation weight accounting for 15% of the mass of the nonwoven substrate (equivalent to 10 g / m 2 ). It was then dried at 160°C for 5 minutes and sintered at 400°C for 10 minutes. Next, a coating was applied to the substrate obtained in this way to form a planar microporous layer. The composition of the coating agent used to form the microporous layer was 10% PTFE, 10% PEEK and 80% carbon black. The fiber material was then dried at 160°C and sintered at 400°C. The final loading of the microporous layer was 23 g / m 2 A coating was then applied over the microporous layer to form the nanoporous layer. The composition of the coating agent used to form the nanoporous layer was 2% PTFE, 2% PEEK, 11% nanoporous carbon, and 0.08% surfactant additive dissolved in distilled water. The substrate was then dried at 160°C and sintered at 400°C. The final loading of the nanoporous layer was 15 g / m 2 .

[0158] Table 2 lists the permeabilities and selectivities achieved for the materials in Example 2.

[0159] Table 2

[0160] Air hydrogen butane <![CDATA[C4H 10 / H2 Selectivity]]> <![CDATA[Pure gas permeability [L / m 2 ·s·Pa]]]> 4.095E-09 1.17E-08 1.395E-08 1.2 <![CDATA[Mixed gas permeability [L / m 2 ·s·Pa]]]> 6.0E-11 6.6E-09 91.7

Claims

1. A membrane device for selective gas separation, comprising: a) a flat, air-permeable carrier material, and b) a nanoporous carbon-containing layer on at least one side of the support material, wherein the nanoporous layer comprises at least one carbon component in a polymer binder, and wherein the nanoporous carbon-containing layer has an average pore size in the range of 0.3 nm to 2.0 nm and a pore size distribution in the range of 0.1 nm to 5.0 nm.

2. A membrane device for selective gas separation, comprising: a) a flat, breathable carrier material, a / b) a microporous layer located on at least one side of the support material, b) a nanoporous carbon-containing layer on the microporous layer a / b), wherein the nanoporous layer comprises at least one carbon component in a polymer binder, and wherein the nanoporous carbon-containing layer has an average pore size in the range of 0.3 nm to 2.0 nm and a pore size distribution in the range of 0.1 nm to 5.0 nm.

3. The membrane device according to claim 1 or 2, wherein the nanoporous carbon-containing layer b) has an average pore size in the range of 0.4 nm to 1.5 nm, preferably in the range of 0.5 nm to 1.3 nm. 4 . The membrane device according to claim 1 , wherein the nanoporous carbon-containing layer b) has a layer thickness in the range of 0.5 μm to 500 μm, preferably in the range of 1.0 μm to 10 μm.

5. The membrane device according to claim 1 , wherein the nanoporous carbon-containing layer b) has a porosity in the range of 20% to 80%, preferably in the range of 60% to 70%, the porosity being determined as the ratio of the pore volume fraction to the total volume of the nanoporous carbon-containing layer.

6. The membrane device according to any of the preceding claims, wherein the planar gas-permeable carrier material a) is selected from fibrous materials, porous metal carriers, porous ceramic and non-ceramic carriers, monolithic carriers, gas-permeable polymer carriers and combinations thereof. 7 . The membrane device according to claim 1 , wherein the carrier material a) comprises or consists of at least one planar fiber material, wherein the carrier material is preferably selected from the group consisting of nonwovens, braids, knits, paper and combinations thereof.

8. The membrane device according to claim 7, wherein the planar fiber material a) is selected from the group consisting of carbon fiber nonwovens, carbon fiber braids, carbon fiber papers, and combinations thereof.

9. A membrane device according to any of the preceding claims, wherein the nanoporous carbon-containing layer b) comprises at least one carbon component selected from carbon black, graphite, graphene, carbon nanotubes (CNTs), carbon nanofibers, in particular graphitic carbon nanofibers (GCNFs), carbon-containing products produced during the production of the nanoporous carbon-containing layer b) and mixtures thereof.

10. The membrane device according to any of the preceding claims, wherein the nanoporous carbon-containing layer b) comprises a polymer binder comprising at least one fluorine-containing polymer b1) and / or at least one fluorine-free, high-temperature-resistant polymer b2).

11. The membrane device according to claim 10, wherein the nanoporous carbon-containing layer b) comprises a polymer binder comprising at least one fluoropolymer b1) selected from polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymers, perfluoroalkoxy polymers and mixtures thereof.

12. A membrane device according to claim 10 or 11, wherein the nanoporous carbon-containing layer b) comprises a polymer binder, the polymer binder comprising at least one fluorine-free, high-temperature resistant polymer b2), the fluorine-free, high-temperature resistant polymer b2) being selected from polyaryletherketone, polyphenylene sulfide, polysulfone, polyethersulfone, partially aromatic (co)polyamide, polyimide, polyamideimide, polyetherimide and a mixture thereof.

13. The membrane device according to claim 1, comprising a microporous layer a / b), wherein the microporous layer a / b) has an average pore size in the range of 5 nm to 10 μm, preferably in the range of 7 nm to 1 μm, in particular in the range of 10 nm to 900 nm. 14 . The membrane device according to claim 1 , comprising a microporous layer a / b), wherein the microporous layer a / b) is free of added transition metal compounds. 15 . The membrane device according to claim 1 , comprising a microporous layer a / b), wherein the microporous layer a / b) is free of added fibers, in particular free of added carbon fibers. 16 . The membrane device according to claim 1 , comprising means for supplying the starting gas mixture and means for discharging at least one gas stream obtained in the gas separation process.

17. A method of manufacturing a membrane device, wherein: i) providing a flat, air-permeable carrier material a), ii) coating the support material provided in step i) with a coating agent to form a nanoporous carbon-containing layer, The pores have an average pore size ranging from 0.3 nm to 2 nm and a pore size distribution ranging from 0.1 nm to 5.0 nm.

18. A method of manufacturing a membrane device, wherein: i) providing a flat, air-permeable carrier material a), ii-a) coating the support material provided in step i) with a coating agent to form a microporous layer, ii-b) coating the coated support material obtained in step ii-a) with a coating agent to form a nanoporous carbon-containing layer, wherein the pores have an average pore size in the range of 0.3 nm to 2 nm and a pore size distribution of 0.1 nm to 5.0 nm.

19. The method of claim 17, wherein: i1) providing a fiber composition as the flat, air-permeable carrier material, the fiber composition comprising carbon fibers and / or carbon fiber precursors, i2) subjecting the fiber composition provided in step i1) to a nonwoven fabric manufacturing process, i3) subjecting the nonwoven fabric to pyrolysis at a temperature of at least 1000° C. if the fiber composition used in step i1) comprises carbon fiber precursors, ii) coating the nonwoven fabric obtained in step i2) or i3) with a nanoporous layer.

20. A membrane device obtainable by a method as defined in any one of claims 17 to 19.

21. A process for at least partially separating at least one gas component from a gas mixture, wherein the starting gas mixture is separated into at least one retentate stream and at least one permeate stream in at least one membrane separation stage, wherein the membrane separation stage comprises at least one membrane device as defined in any one of claims 1 to 16 or obtainable by a process as defined in any one of claims 17 to 19.

22. The method according to claim 21, wherein the starting gas mixture used is a gas mixture from large-scale hydrogen production, preferably a gas mixture from hydrogen production by steam methane reforming (SMR), a gas mixture from the water gas shift reaction, synthesis gas from coal gasification, synthesis gas from crude oil, synthesis gas from carbonaceous waste or synthesis gas from biomass, or a gas mixture from the partial oxidation of hydrocarbons.

23. The method according to claim 21 or 22, wherein the starting gas mixture comprises hydrogen and at least one C1-C 14 Hydrocarbons, preferably at least one C1-C6 hydrocarbon, in particular selected from CH4, C2H6, C3H8 and C4H 10 C1-C6 hydrocarbons.

24. The method according to claim 23, wherein the starting gas mixture further comprises at least one additional gas component, preferably selected from the group consisting of CO, CO2, N2 and mixtures thereof.

25. Use of a membrane device as defined in any one of claims 1 to 16 or obtainable by a process as defined in any one of claims 17 to 19 for selective gas separation, preferably for selective separation of gas mixtures from large-scale hydrogen production, in particular for selective separation of gas mixtures comprising hydrogen and at least one C1-C 14 Use of a gaseous mixture of hydrocarbons, preferably at least one C1-C6 hydrocarbon.