Nanoporous membranes and their use for gas separations

Abstract

The present invention relates to a method for producing nanoporous carbon membranes, to the membranes obtained by this method, to a method for gas separation using this membrane, and to the use of such membranes.

Description

[Technical Field]

[0001] The present invention relates to a method for producing nanoporous carbon membranes, to the membranes obtained by this method, to a method for gas separation using this membrane, and to the use of such membranes. [Background technology]

[0002] The separation of gas mixtures is becoming increasingly important with regard to the efficient utilization of gas streams from existing processes and also 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, optionally, further light gases such as carbon monoxide. Currently, the separation of such gas mixtures is still often carried out by cryogenic distillation, a process that is very energy-intensive and involves high capital expenditures.

[0003] On the other hand, for energy conversion, it is necessary to use hydrocarbon streams such as methane from sources that contain significant amounts of other gas impurities, such as carbon dioxide or nitrogen. To make biogas or natural gas from sources with a higher proportion of other gases usable, purification is usually required to meet technical requirements for feeding into gas supply networks, etc. Special requirements are imposed on the purity of methane-containing gas streams in the case of liquefaction and transportation through pipelines or by ship.

[0004] On the other hand, as part of the transformation of the energy industry towards a low-carbon energy system, there is a high demand for hydrogen, whenever possible from renewable sources, existing large-scale industrial processes, or carbon-containing waste, especially plastic waste. Hydrogen is an extremely efficient and clean energy carrier, with only water produced as a by-product during its conversion to energy, is suitable for many storage methods, and is considered to be a key element in the development of solutions to global climate change. Currently, large-scale hydrogen production is usually carried out by methane steam reforming (SMR), coal gasification, or partial oxidation of hydrocarbons. These hydrogen production methods require the production of further gas components such as CO, CO2, N2, and / or CH4, C2H6, C3H8, C4H 10 A hydrogen-rich stream (syngas / oxo gas, etc.) is obtained, containing lower hydrocarbons such as

[0005] Steam reforming is a process in which a carbon-containing fuel, such as natural gas (the main component of which is methane), is reacted with water steam. Partial oxidation of the fuel occurs, producing hydrogen, as in the conversion of methane: CH4 + H2O → CO + 3H2. The yield of hydrogen increases further if carbon monoxide (CO) is further oxidized to carbon dioxide (CO2): CO + H2O → CO2 + H2. This reaction is called the water-gas shift reaction.

[0006] Syngas is a gas containing hydrogen and carbon monoxide that can be used in various chemical syntheses. The traditional route for producing syngas is coal gasification with the addition of steam and oxygen. In this process, oxygen is extracted from water (H2O), and this oxygen, together with directly introduced oxygen, oxidizes the coal to carbon monoxide and, partially, carbon dioxide. A mixture of hydrogen (H2), carbon monoxide (CO), carbon dioxide (CO2), and various impurities (e.g., sulfur compounds due to the sulfur content of the coal) is produced. Gas cleaning is often performed before further processing to separate carbon black and metals, dry (remove unconverted steam), separate CO2, and / or separate sulfur compounds. Petroleum fractions and natural gas can also be used to produce syngas. Furthermore, recycling carbon-containing waste materials, such as plastic waste (e.g., from "yellow bag" waste collection), into syngas and even building blocks such as methanol has recently become important, thereby addressing both the waste problem and the circular economy.

[0007] Gas separation and concentration by gas separation membranes is a method that has various advantages compared to other methods such as distillation or high-pressure adsorption, such as greater flexibility and safety, generally lower capital costs, and good energy efficiency. Membrane processes have long been used to separate gases based on their size and / or affinity.

[0008] The use of nanoporous carbon membranes for the separation of hydrogen / hydrocarbon mixtures is known. MB Rao and S. Sircar, in Journal of Membrane Science 110 (1996), 109–118, describe the use of nanoporous carbon membranes capable of selectively adsorbing hydrocarbons from their mixtures with hydrogen on the high-pressure side, allowing the adsorbed gas molecules to diffuse through the membrane pores to the low-pressure side. To fabricate the membrane, a layer of polyvinylidene chloride latex is deposited on an aluminum oxide support and carbonized at 600–1000 °C in an inert atmosphere. A corresponding product from Air Products and Chemicals, called the “SSF membrane,” proved economically unviable and was not widely adopted.

[0009] U.S. Patent Application Publication No. 2022 / 040644 describes a membrane for purifying or separating hydrogen from a gas stream containing multiple components, such as synthesis gas. It is a multi-stage hybrid membrane comprising a sieve-like support material and two layers thereon, both of which contain carbon fiber, a transition metal compound, a fluorine-containing polymer, and activated carbon or small-pore carbon. The activated carbon used in the membrane layers has nanopores with diameters of less than 3 nm. This document does not provide information on the pore size of the hybrid membrane layers. Therefore, U.S. Patent Application Publication No. 2022 / 040644 does not explicitly describe a membrane device for selective gas separation having a nanoporous carbon-containing layer with an average pore size in the range of 0.3 to 2.0 nm and a pore size distribution in the range of 0.1 to 5.0 nm.

[0010] U.S. Patent No. 9,694,344 describes a multilayer polymer membrane containing a sorbent material and numerous interconnected pores, and a single-step coextrusion process for its manufacture. The sorbent material can be, among other things, a carbon-containing material. The membrane can have up to about 100 layers, each with a different pore structure. The interconnected pores generally exhibit average diameters ranging from about 0.01 nm to about 50 μm.

[0011] Known membranes do not yet have an appropriate property profile for all separation tasks, in particular known manufacturing methods are very cumbersome and do not allow modifying the membrane properties to adapt them to the respective separation task.

[0012] There is a demand for membrane devices for selective gas separation, particularly for separating gas mixtures containing hydrocarbons and hydrogen. It would be desirable to be able to dispense with cumbersome manufacturing methods, such as layer-by-layer coating of porous support materials, e.g., aluminum oxide, followed by carbonization. It would also be desirable for this manufacturing method to allow the separation characteristics to be adapted as easily as possible to various separation problems. In particular, the problem underlying the present invention is to provide a membrane device for selective gas separation, particularly for separating hydrocarbons, particularly C1-C6. 14 The present invention provides a permselective membrane for separating hydrocarbons, more particularly C1 to C6 hydrocarbons, and even more particularly C1 to C4 hydrocarbons, from a hydrogen-containing gas mixture.

[0013] Surprisingly, it has now been found that this problem is solved by a membrane device and a method for producing a membrane device, in which a porous support material is coated with a nanoporous carbon-containing layer of predetermined pore size and pore size distribution.

[0014] Summary of the Invention The first object of the present invention is to a) a planar gas-permeable carrier material; b) a nanoporous carbon-containing layer on at least one of the faces of the support material, the nanoporous layer comprising at least one carbon component in a polymer binder, the nanoporous carbon-containing layer preferably having an average pore size in the range of 0.3 to 2.0 nm and a pore size distribution in the range of 0.1 to 5.0 nm; A membrane device for selective gas separation comprising:

[0015] A further object of the present invention is a) a planar gas-permeable carrier material; a / b) a microporous layer on at least one of the faces of the support material; b) a nanoporous carbon-containing layer on the microporous layer a / b), the nanoporous layer comprising at least one carbon component in a polymer binder, the nanoporous carbon-containing layer having an average pore size in the range of 0.3 to 2.0 nm and a pore size distribution in the range of 0.1 to 5.0 nm; and A membrane device for selective gas separation comprising:

[0016] The determination of the average pore size and the pore size distribution of the nanoporous layer is carried out in particular by means of permeation porosimetry.

[0017] The present invention further provides a method of manufacturing a membrane device, comprising: i) providing a planar gas-permeable carrier material a); ii) coating the support material prepared in step i) with a coating agent to form a nanoporous carbon-containing layer; The pores have an average pore diameter in the range of 0.3 to 2 nm and a pore diameter distribution in the range of 0.1 to 5.0 nm. Regarding the method: The determination of the average pore size and the pore size distribution is carried out in particular by permeation porosimetry.

[0018] The present invention further provides a method of manufacturing a membrane device, comprising: i) providing a planar gas-permeable carrier material a); ii-a) coating the support material prepared 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, the pores having an average pore size in the range of 0.3 to 2 nm and a pore size distribution in the range of 0.1 to 5.0 nm; Regarding the method.

[0019] Preferably, step i) of both methods listed above comprises: i1) providing a fiber composition containing carbon fibers and / or precursors of carbon fibers as a planar, gas-permeable carrier material; i2) subjecting the fiber composition prepared in step i1) to a method for producing a nonwoven fabric, i3) if the fiber composition used in step i1) comprises precursors of carbon fibers, subjecting the nonwoven fabric to pyrolysis at a temperature of at least 1000°C. This includes:

[0020] A preferred embodiment is i1) providing a fiber composition containing carbon fibers and / or precursors of carbon fibers as a planar, gas-permeable carrier material; i2) subjecting the fiber composition prepared in step i1) to a method for producing a nonwoven fabric, i3) if the fiber composition used in step i1) comprises precursors of carbon fibers, subjecting the nonwoven fabric to pyrolysis at a temperature of at least 1000°C, ii) coating the nonwoven fabric obtained in step i2) or i3) with a nanoporous layer; It is a method.

[0021] A further subject of the present invention is a membrane device obtainable by the method defined above and below.

[0022] A further subject of the present invention is a process for at least partially separating at least one gas component from a gas mixture, which process comprises subjecting a starting gas mixture to separation into at least one retentate stream and at least one permeate stream in at least one membrane separation stage, the membrane separation stage comprising at least one membrane device as defined above and below or obtainable by a process as defined above and below.

[0023] A further object of the present invention is to provide a process for selective gas separation, preferably for the selective separation of gas mixtures from large-scale industrial hydrogen production, in particular for the selective separation of hydrogen and at least one C1-C 14 Use of a membrane device as defined above and below or obtainable by the process as defined above and below for the selective separation of a gas mixture containing hydrocarbons, preferably at least one C1-C6 hydrocarbon.

[0024] Description of the Invention The membrane device according to the invention for selective gas separation and its production by coating a support material with a nanoporous carbon-containing layer has the following advantages: The membrane devices according to the invention have the advantage of low space requirements and a simple, flexible and, if necessary, movable plant design compared to conventional methods such as rectification at low temperatures, physical or chemical absorption, adsorption on activated carbon or zeolites, etc., and these devices are generally further characterized by low investment costs and low energy requirements. Furthermore, the configuration of the gas separation is possible as a continuous process with only one stage. This production can be carried out by established techniques for coating planar support materials, in particular planar fibrous materials, with porous carbon-containing layers, eliminating the need for complex, partially multi-stage coating of inert solid inorganic supports and subsequent adjustment of the selectivity by carbonization. Without being bound by theory, it is assumed that the mechanism of gas separation by the membrane device of the present invention occurs partially or completely by capillary condensation. In particular, gas separation is carried out by the nanoporous carbon-containing layer by capillary condensation, a transport process that typically occurs in small-pore membranes when gaseous components can condense within the membrane pores. The membrane device of the present invention is 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. Here, extremely high selectivities can be achieved with respect to the components (usually hydrocarbons) that permeate the membrane. - The membrane device is characterized by high temperature and pressure resistance.

[0025] Transmittance is m 2 It refers to the flow rate of gas in standard cubic meters per membrane area, time, and pressure, where pressure is the partial pressure difference between the feed / retentate and permeate of the corresponding gas. The permeation selectivity is obtained from the ratio of the specified permeabilities of the individual components of the gas mixture to be separated.

[0026] Advantageously, the membrane device according to the present invention has a permeability to hydrocarbons such that it is possible to separate the hydrocarbons from a gas mixture having at least one light gas selected from hydrogen, carbon monoxide, carbon dioxide, nitrogen, and mixtures thereof.

[0027] The determination of the pore size and pore size distribution of nanoporous carbon-containing layers can be carried out by permeation porosimetry. The principle of permeation porosimetry is based on the controlled stepwise blocking of the pores by capillary condensation of the condensable components of a gas mixture, while simultaneously measuring the gas flow through the membrane. This principle is described, for example, by FC Cuperus et al. in J. Membrane Sci. 71 (1992), 57-67. Commercially available instruments can be obtained from Porometer, APTCO TECHNOLOGIES NV, Belgium. Olga Solcova et al., 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, describe the application of permeation porosimetry in materials with greater thickness and a wide distribution of pore sizes.

[0028] The nanoporous carbon-containing layer has an average pore size, determined by permeation porosimetry, in the range of 0.3 to 2.0 nm, preferably 0.4 to 1.5 nm, particularly preferably 0.5 to 1.3 nm.

[0029] The nanoporous carbon-containing layer has a pore size distribution in the range of 0.1 to 5.0 nm, as determined by permeation porosimetry.

[0030] Preferably, the nanoporous carbon-containing layer has a layer thickness in the range of 0.5 to 500 μm, particularly preferably 1.0 to 10 μm.

[0031] Preferably, the nanoporous carbon-containing layer has a porosity, determined as the ratio of the volume fraction of pores to the total volume of the nanoporous carbon-containing layer, in the range of 20 to 80%, particularly preferably 60 to 70%. The determination of the volume fraction of pores can be carried out by permeation porosimetry.

[0032] Planar support material a) The membrane device according to the invention for selective gas separation comprises at least one planar, gas-permeable support material a).

[0033] Preferably, the areal gas-permeable support material a) is selected from fibrous materials, porous metal supports, porous ceramic and non-ceramic supports, monolithic supports, gas-permeable polymer supports, and combinations thereof.

[0034] Suitable fibrous materials include organic fibers, inorganic fibers, and combinations thereof. Preferably, the fibrous materials include synthetic polymer fibers, natural polymer fibers, carbon fibers, metal fibers, ceramic fibers, glass fibers, basalt fibers, silica fibers, mineral fibers, and combinations thereof.

[0035] In a preferred embodiment, the carrier material a) comprises or consists of at least one planar fibrous material, the carrier material being preferably selected from nonwoven fabrics, woven fabrics, knitted fabrics, paper, and combinations thereof.

[0036] In the context of the present invention, fleece generally refers to a sheet-like structure consisting largely of individualized fibers whose cohesion is essentially solely due to their inherent adhesive forces. The conversion of fleece into a nonwoven fabric by creating stronger connections between the fibers than exist in the fleece is achieved by nonwoven consolidation methods, which are often divided into mechanical, chemical, and thermal methods. Fleeces, nonwoven fabrics, and methods for their production are described in H. Fuchs, W. Albrecht, Vliesstoffe, 2. Auflage, Wiley-VCH, Weinheim, Germany.

[0037] Suitable porous metal supports are, for example, porous metals such as aluminum, or woven metal fabrics.

[0038] Suitable inorganic supports are, for example, porous ceramic and non-ceramic supports. Suitable support materials include clay minerals, aluminum oxide, silicon oxide, aluminosilicates, in particular zeolites, zirconium dioxide, titanium dioxide, yttrium oxide, further metal oxides, glass, silicon nitride, silicon carbide, Si—CO, Si—CNO, Si—BNC, etc., and combinations thereof.

[0039] Furthermore, suitable supports are monolithic supports. Such supports and methods for their production are known to those skilled in the art.

[0040] Further suitable carriers are gas-permeable polymeric carriers, for example selected from polyamides, polyimides, polypyrrolones, polyesters, polysulfones, polymeric organosilicones, fluorine-containing polymers, polyolefins, and copolymers and mixtures (blends) thereof.

[0041] The membrane device and / or the support material a) can in principle have any shape suitable for the intended application. The shape of the base region of the membrane device and / or the support material can be, for example, polygonal (n-gonal, where n≧3, for example, triangular, square, pentagonal, hexagonal, etc.), circular, part-circular (for example, semicircular), elliptical, or part-elliptical. Preferably, the base region is rectangular or circular. The membrane device can be designed, for example, as a substantially planar disk (plate-shaped), tubular, honeycomb, or polygonal prism. Furthermore, the membrane device can have a support device or can be designed to be free-standing.

[0042] The support material may be composed of one or more layers, for example, two, three, four, five, or more than five layers. The layers may be composed of different support materials, or may be composed of the same support material that differs in their composition and / or other physicochemical properties, such as porosity or pore size distribution. Each individual layer may also be composed of a composite material. Such a composite material may, for example, have at least one porous substrate and at least one porous or non-porous support material (e.g., a fibrous material or a polymeric support), and optionally at least one binder. Suitable porous substrates include, for example, porous metals, porous ceramic and non-ceramic materials, porous glass, etc.

[0043] Here, the support material may have an asymmetric, particularly gradient-shaped, layer structure. For example, the nanoporous carbon-containing layer b) can be arranged on the support material from at least two layers with different porosities. In a gradient-shaped layer structure, for example, the porosity may decrease continuously in the direction of the nanoporous carbon-containing layer.

[0044] Optionally, the support material may have at least one inorganic layer. The inorganic layer may be disposed, for example, between the nanoporous carbon-containing layer b) and at least one further support layer. The inorganic layer may, for example, have a large number of discrete particles. These particles preferably have a particle size of up to 1 micrometer, in particular up to 500 nm. The particles in the inorganic layer may be selected, for example, from alkaline earth metal oxide particles, transition metal oxide particles, lanthanide metal oxide particles, group (IVA) metal oxide particles, transition metal particles, metal alloy particles, silicate particles, aluminosilicate particles, zeolite particles, clay mineral particles, and combinations thereof. Particle size analysis may be performed by laser diffraction in accordance with ISO 13320:2020-01.

[0045] Preferably, the membrane device according to the present invention comprises at least one planar fibrous material as component a). In particular, component a) comprises a fibrous material selected from nonwoven fabrics, woven fabrics, knitted fabrics, paper, and combinations thereof. Fibers suitable for the fibrous material a) are, in principle, carbon fibers, glass fibers, fibers of organic polymers such as polyolefins, polyesters, polyamides, and mixtures thereof. The fibers contained in the fibrous material a) comprise or preferably consist of carbon fibers. Such fibrous materials particularly advantageously meet requirements such as gas diffusion and heat transfer. The support material a) is preferably selected from woven carbon fiber fabrics, carbon fiber paper, and nonwoven carbon fiber fabrics. In a particularly preferred embodiment, the support material a) comprises at least one nonwoven carbon fiber fabric or consists of a nonwoven carbon fiber fabric.

[0046] Carbon fibers can be produced by conventional methods, and polyacrylonitrile fibers (PAN fibers) are preferably used as the starting material.

[0047] Carbon fiber woven fabrics are produced by crossing two yarn systems, warp (warp threads) and weft (filler threads). Similar to textiles, the fiber bundles are flexible yet inseparably connected to one another. The carbon fiber woven fabrics are preferably made from PAN fibers that have been oxidized but not yet carbonized or graphitized. After weaving, the planar fiber material is carbonized or graphitized to impart electrical conductivity.

[0048] For the production of carbon fiber paper, oxidized PAN fibers are preferably used. These are chopped into fiber fragments in a manner known per se, slurried, and a fiber mat is produced and dried by screening (using a sieve), similar to papermaking. In a preferred embodiment, at least one binder is further incorporated into the paper. Suitable binders are, for example, phenolic resins, furan resins, polyimide resins, etc. To incorporate the binder, the paper can be impregnated with the binder and then optionally cured. After impregnation and curing, the carbon fiber paper is again subjected to carbonization / graphitization, which also converts the binder into a compound with improved electrical conductivity. In a further suitable embodiment, filled carbon fiber paper is used to prepare the carrier material a). The production is first carried out as described above, but instead of binder introduction and carbonization / graphitization, a filler is introduced into the still-wet paper from a carbon material in a polymer binder. For this purpose, a carbon PTFE filler is particularly used. This loading improves thermal and electrical conductivity, which may eliminate the need for carbonization / graphitization.

[0049] To produce carbon fiber nonwoven fabrics, either non-oxidized or oxidized PAN fibers can be used. In a first preferred embodiment, the fibers are first carded into a web in a dry state and then consolidated into a nonwoven fabric. This can be done, for example, by hydroentangling, in which the carbon fibers are oriented, entangled, and thus mechanically stabilized. If necessary, the thickness of the consolidated nonwoven fabric can be calibrated to the desired value. Nonwoven fabrics based on non-oxidized PAN fibers are first subjected to oxidation at high temperature in an oxygen atmosphere after nonwoven fabric laying and solidification, and then to carbonization / graphitization in an inert gas atmosphere. Nonwoven fabrics based on oxidized PAN fibers are only subjected to carbonization / graphitization after nonwoven fabric laying and solidification.

[0050] In a first specific embodiment, a mechanically bonded fiber material is used as the carrier material a). In a further specific embodiment, a nonwoven fabric is used as the fiber material a) into which at least one binder is incorporated, which is then optionally cured. Suitable binders are, for example, phenolic resins, furan resins, polyimide resins, etc.

[0051] In a specific embodiment, a nonwoven fabric incorporating at least one fluorine-free, high-temperature-resistant polymer as a fiber material and / or binder is used as the carrier material a). In this case, the fluorine-free, high-temperature-resistant polymer is selected from polyaryletherketone, polyphenylene sulfide, polysulfone, polyethersulfone, semi-aromatic (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 in addition to or instead of 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 incorporated after carbonization / graphitization, and the resulting impregnated fleece can then be treated with heat again (for drying and / or sintering).

[0052] The areal carrier material a) is preferably a fiber composite element comprising a fiber material which is preferably selected from nonwoven carbon fiber fabrics, woven carbon fiber fabrics and mixtures thereof.

[0053] In particular, the fiber composite component comprises at least one fiber material and, applied to and / or incorporated into it, at least one polymer additive a1) and optionally at least one further additive a2).

[0054] The polymer additive a1) is preferably selected from fluorine-containing polymers a11), fluorine-free high-temperature resistant polymers a12), polymers a13) different therefrom, and mixtures thereof.

[0055] Preferably, the mass fraction of the polymer additive a1) is 0.5 to 50%, preferably 1 to 40%, based on the mass of the fibrous material used as carrier material a).

[0056] In a specific embodiment, the polymer additive a1) comprises at least one fluorine-containing polymer a11). In this case, the mass fraction of the fluorine-containing polymer a11) is preferably 0.5 to 40%, preferably 1 to 30%, based on the mass of the fibrous material used as the support material a). The addition of at least one fluorine-containing polymer a11) can improve the hydrophobicity of the fibrous material used as the support material a), which can favorably affect the transport process through the membrane device. In principle, the fluorine-containing polymer a11) is a fluorine-containing polymer b1) used as a polymer binder in the nanoporous layer. The fluorine-containing polymer a11) is preferably selected from polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), perfluoroalkoxy polymer (PFA), and mixtures thereof. The perfluoroalkoxy polymer is, for example, a copolymer of tetrafluoroethylene (TFE) and a perfluoroalkoxy vinyl ether, such as perfluorovinyl propyl ether. Preferably, polytetrafluoroethylene is used as polymer a11).The fibrous material can be treated with the fluorine-containing polymer a11) by a conventional impregnation method.For example, a PTFE dispersion is applied in a dipping bath, the solvent is evaporated, and the treated fibrous material is sintered at high temperatures, generally at least 300 ° C.

[0057] In a further specific embodiment, the polymer additive a1) comprises 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, semi-aromatic (co)polyamides, polyimides, polyamideimides, polyetherimides, and mixtures thereof. In this case, the mass fraction of the fluorine-containing polymer a12) is preferably 0.5 to 40%, preferably 1 to 30%, based on the mass of the fibrous material used as the carrier material a).

[0058] 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 which the total mass fraction of polymers a11) and a12) is preferably 0.5 to 40%, preferably 1 to 30%, based on the mass of the fibrous material used as the carrier material a).

[0059] The polymer additive a1) may contain at least one additional polymer a13) different from a11) and a12). Suitable polymer a13) is, for example, selected from phenolic resins, furan resins, polyimide resins, and mixtures thereof. In particular, the polymer additive a1) contains an additional polymer a13) different from the fluorine-containing polymer a11) and polymer a12) in a weight fraction of up to 5%, preferably up to 1%, particularly preferably up to 0.5%, in particular up to 0.1%, based on the total weight of the fiber material A). Even more particularly, the fiber material a) does not contain an additional polymer a13) different from the fluorine-containing polymer a11) and polymer a12).

[0060] The fibrous material used as the support material a) may further contain at least one additive a2). Suitable additives include fillers and reinforcing agents, surface-active compounds, adhesion promoters, etc. Preferably, the additive a2) is selected from metal particles, carbon black, graphite, graphene, carbon nanotubes (CNTs), carbon nanofibers, and mixtures thereof. A specific embodiment of the carbon nanofibers is graphitic carbon nanofibers (GCNFs). Particularly preferably, the additive a2) comprises or consists of carbon black. The treatment of the fibrous material a) with at least one additive a2) can be carried out, for example, together with the polymer additive a1).

[0061] Preferably, the mass fraction of additive a2) is 0 to 80%, particularly preferably 0 to 50%, based on the mass of the fibrous material used as support material a). In a special embodiment, additive a2) comprises or consists of carbon black. In this case, the mass fraction is preferably 0.5 to 45%, particularly preferably 1 to 25%, based on the mass of the fibrous material used as support material a).

[0062] The fiber material a) preferably has a thickness in the range of 50 to 500 μm, particularly preferably 100 to 400 μm, in the untreated, uncompressed state of the fiber material a), i.e., before incorporation into the membrane device.

[0063] The fibrous material used as carrier material a) can be treated with components a1) and / or a2) by conventional methods. Preferably, an aqueous dispersion is used to treat the fibrous material. Suitable coating and impregnation methods are described in more detail below.

[0064] In a particular embodiment, the fiber material treated with components a1) and / or a2) is subjected to a heat treatment (drying and / or sintering). Preferably, the heat treatment of the fiber material is carried out at a temperature of at least 250° C., particularly preferably at least 300° C., in particular in the range from 300 to 450° C. The heat treatment can also be carried out after the deposition of the nanoporous carbon-containing layer b), as described more precisely below.

[0065] Nanoporous carbon-containing layer b) The membrane device according to the invention comprises a two or more layer composite based on a planar gas-permeable support material a) and a nanoporous carbon-containing layer b) on at least one of the faces of the support material a).

[0066] In particular, the nanoporous layer b) comprises at least one carbon component in a polymer binder. Furthermore, at least one additive can be used to produce the nanoporous layer. Suitable additives are, for example, pore-forming agents.

[0067] 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 from the production of the nanoporous carbon-containing layer b), and mixtures thereof. Preferably, carbon black, graphite, or mixtures thereof are used.

[0068] In particular, the polymer binder contains at least one fluorine-containing polymer b1), which is preferably selected from polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymers, perfluoroalkoxy polymers, and mixtures thereof. Preferably, polytetrafluoroethylene is used as polymer b1).

[0069] Alternatively or additionally, the polymer binder contains at least one fluorine-free, high-temperature resistant polymer b2), which is preferably selected from polyaryletherketones, polyphenylene sulfides, polysulfones, polyethersulfones, semi-aromatic (co)polyamides, polyimides, polyamideimides, polyetherimides, and mixtures thereof.

[0070] In certain embodiments, the polymer binder comprises at least one polymer b1) and at least one polymer b2), where b1) comprises or consists of polytetrafluoroethylene (PTFE) and b2) comprises or consists of polyetheretherketone (PEEK).

[0071] In particular, polymer b2) is selected from so-called high-performance plastics, which are characterized by properties such as a high glass transition temperature, a high melting point, good temperature resistance, good chemical resistance, and good mechanical properties. Preferably, polymer b2) has a long-term operating temperature (continuous use temperature) of at least 150° C. In particular, polymer b2) is a thermoplastic resin.

[0072] As polymers b2) semi-aromatic and aromatic polymers are preferred.

[0073] The polymer b2) is preferably selected from polyaryletherketones (PAEK), polyphenylene sulfides (PPS), polysulfones (PSU), polyethersulfones (PES), semi-aromatic (co)polyamides (high temperature polyamides, HTPA), polyimides (PI), polyamideimides (PAI), polyetherimides (PEI), and mixtures (blends) thereof.

[0074] Suitable polymers b2) are also (semi)aromatic polyesters such as PET or PBT, polycarbonates (PC) and temperature-resistant melamines such as melamine foams filled with nanoporous SiO2 aerogel.

[0075] In a preferred embodiment, polymer component b2) comprises at least one polyaryletherketone. In particular, polymer component b2) consists of at least one polyaryletherketone. Polyaryletherketones (PAEK) are semi-crystalline thermoplastic resins with an alternating structure in which aryl groups are each followed by a keto group (carbonyl group) or an ether group, where the proportion of keto and ether groups is variable and the substitution pattern on the aryl ring may differ. Suitable polyaryletherketones b2) are polyetherketones (PEK), polyetheretherketones (PEEK), polyetherketoneketones (PEKK), etc. Preferably, polymer component b2) comprises or consists of at least one polyetheretherketone.

[0076] Suitable semi-aromatic (co)polyamides b2) are polymers known as high-temperature polyamides (HTPA). These are semi-crystalline or amorphous thermoplastic semi-aromatic polyamides. Preferably, they contain at least one aromatic dicarboxylic acid, particularly selected from terephthalic acid, isophthalic acid, and mixtures of terephthalic acid and isophthalic acid, by polymerization. Preferred semi-aromatic (co)polyamides b2) are selected from PA6.T, PA10.T, PA12.T, PA6.I, PA10.I, PA12.I, PA6.T / 6.I, PA6.T / 6, PA6.T / 10T, PA10.T / 6.T, PA6.T / 12.T, PA12.T / 6.T, and mixtures thereof. A further specific embodiment of polyamide b2) is polyphthalamide (PPA).

[0077] Suitable polyimides b2) are polysuccinimide (PSI), polybismaleimide (PBMI), polyimide sulfone (PISO), and polymethacrylimide (PMI).

[0078] In particular, the polymer binder contains at least one fluorine-free high-temperature resistant polymer b2) and at least one fluorine-containing polymer b1) different therefrom. Preferably, at least one polyether ether ketone is used as polymer b2), and polytetrafluoroethylene is used as polymer b1).

[0079] Preferably, for producing the nanoporous layer b), the polymer binder is used 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.

[0080] The nanoporous carbon-containing layer according to the present invention has an advantageous pore structure. It has been found that by using the polymer binder described above as component b2), a larger proportion of pores can be created in the nanoporous layer. The choice of filler and reinforcing agent can also affect the pore size and pore size distribution. For example, the use of graphite, particularly coarse-grained or expandable graphite, generally allows for the creation of larger pores than the use of carbon black. Furthermore, the total pore volume, the number of pores, and their size distribution can be influenced by the use of a pore-forming agent. Suitable pore-forming agents are, for example, commercially available plastic particles such as polymethyl methacrylate (PMMA).

[0081] Preferably, the nanoporous layer has a thickness in the uncompressed state of 5 to 100 micrometers, preferably 10 to 50 micrometers, this thickness referring to the uncompressed state of the nanoporous layer b), i.e. before integration into a complex gas separation device.

[0082] The membrane device according to the invention preferably has a thickness (total thickness from the support material a) and the nanoporous layer b) in the range of 50 to 1000 μm, particularly preferably 75 to 500 μm. This thickness refers to the uncompressed state of the membrane device, i.e., before its integration into a complex gas separation device.

[0083] The thickness of the planar gas-permeable carrier material a), the nanoporous carbon-containing layer b) and the membrane device can be determined according to DIN 53855-1:1993-08 "Bestimmung der Dicke textiler Flaechengebilde".

[0084] g / m 2 The determination of the mass per area (also called basis weight) can be carried out according to EN 29073-1:1992.

[0085] Microporous layer a / b) In a particular embodiment, the membrane device according to the invention comprises a three or more layer composite based on a planar gas-permeable support material a), a microporous layer a / b) on at least one of the faces of the support material a), and a nanoporous carbon-containing layer b) on the microporous layer a / b).

[0086] In particular, the microporous layers a / b) contain conductive particles in a polymer binder matrix. The conductive particles are preferably selected from conductive carbon particles, in particular carbon black, graphite, graphene, carbon nanotubes (CNTs), carbon nanofibers, and mixtures thereof. Preferably, carbon black, graphite, or mixtures thereof are used.

[0087] Preferably, the polymer binder of the microporous layer a / b) comprises at least one polymer selected from fluorine-containing polymers, fluorine-free high temperature resistant polymers, polymers different therefrom, and mixtures thereof.

[0088] In particular, the polymer binder of the microporous layer a / b) comprises at least one fluorine-containing polymer.Suitable fluorine-containing polymers are the fluorine-containing polymers b1) previously described for the formation of the nanoporous layer b), and are referred to here in their entirety.In particular, the polymer binder of the microporous layer a / b) comprises at least one fluorine-containing polymer b1), which is preferably selected from polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, perfluoroalkoxy polymer, and mixtures thereof.Preferably, polytetrafluoroethylene is used as the polymer binder of the microporous layer a / b).

[0089] Alternatively or additionally, the polymer binder of the microporous layer a / b) contains at least one fluorine-free, high-temperature-resistant polymer. Suitable fluorine-free, high-temperature-resistant polymers are the polymers b2) previously described for the formation of the nanoporous layer b), and are referred to herein in their entirety. In particular, the polymer binder of the microporous layer a / b) contains at least one fluorine-containing polymer b2), which is preferably selected from polyaryletherketones, polyphenylene sulfides, polysulfones, polyethersulfones, semi-aromatic (co)polyamides, polyimides, polyamideimides, polyetherimides, and mixtures thereof.

[0090] In a particular embodiment, the polymer binder of the microporous layer a / b) comprises at least one polymer b1) and at least one polymer b2), where b1) comprises or consists of polytetrafluoroethylene (PTFE) and b2) comprises or consists of polyetheretherketone (PEEK).

[0091] Preferably, for producing the microporous layer b), the polymer binder is used 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 conductive particles.

[0092] The application of the microporous layer a / b) to the support material a) can be carried out in various ways. Discontinuous production frequently involves spraying, screen printing, or the Mayer rod method, while continuous coating is preferably carried out using the doctor blade, slot die, or gravure roll processes. Finally, a heat treatment can be carried out, for example, in a drying or sintering furnace. Here, drying is first carried out at temperatures between 100 and 200°C, followed by optional sintering at temperatures between 300 and 500°C.

[0093] In contrast to the macroporous fibrous 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 from 5 nm to 10 μm, particularly preferably in the range from 7 nm to 1 μm, in particular in the range from 10 nm to 900 nm.

[0094] The porosity and pore size distribution of the microporous layers a / b) can be determined by mercury porosimetrie, as described in DIN ISO 15901-1:2019-03 and ISO 15901-1:2016 Teil 1: Quecksilberporosimetrie.

[0095] In a special embodiment, the microporous layer a / b) is free of added transition metal compounds.

[0096] In a special embodiment, the microporous layer a / b) is free of added fibers, in particular without added carbon fibers.

[0097] Preferably, the microporous layer a / b) has a thickness in the range of 5 to 150 μm, particularly preferably 10 to 100 μm, in the uncompressed state of the microporous layer a / b), i.e. before installation in the membrane device.

[0098] Manufacturing method A further object of the present invention is a method for producing a membrane device, comprising the steps of: i) providing a gas-permeable carrier material a) in the form of a sheet; ii) coating the support material prepared in step i) with a coating agent to form a nanoporous carbon-containing layer, the pores having an average pore size in the range of 0.3 to 2 nm and a pore size distribution in the range of 0.1 to 5.0 nm, both preferably determined by permeation porosimetry; It is a method.

[0099] A further object of the present invention is a method for producing a membrane device, comprising the steps of: i) providing a gas-permeable carrier material a) in the form of a sheet; ii-a) coating the support material prepared 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, the pores having an average pore size in the range of 0.3 to 2 nm and a pore size distribution in the range of 0.1 to 5.0 nm; It is a method.

[0100] The planar, gas-permeable support material a) provided in step i) of the method described above may have one or more layers. In this regard, reference is made to the above paragraphs regarding suitable support materials. In a preferred embodiment, the support material a) comprises at least one planar fibrous material. In a specific embodiment, a nanoporous carbon-containing layer b) is applied to the planar fibrous material, even in the case of a multi-layer structure of the support material a). The planar fibrous material is preferably selected from nonwoven fabrics, woven fabrics, knitted fabrics, paper, and combinations thereof. Reference is made to the above paragraphs regarding suitable and preferred fibrous materials. The fibrous material can be treated with conventional binders and / or additives before use in step ii), as also described above. Conventional impregnation methods can be used for this purpose. The optionally treated fibrous material can be subjected to a heat treatment (drying and / or sintering) before use in step ii).

[0101] The carrier material a), in particular the fiber material, prepared in step i) can optionally be coated with a coating agent in step a / b) to form a microporous layer. Possible procedures for applying the microporous layer a / b) to the carrier material a) have already been described above.

[0102] In a first embodiment, the support material a) prepared in step i), in particular a fiber material, is coated with a coating agent in step ii) to form a nanoporous layer b). Preferably, the support material is coated and / or impregnated with an aqueous composition containing at least one carbon component, a polymer binder, and, if necessary, further additives. Here, all components for forming the nanoporous layer can be used in a single composition for coating the support material a). It is also possible to coat the support material a) with two or more coating agents, each containing one or more components. Regarding suitable and preferred polymers b1) and b2), reference is made to the above explanations in their entirety.

[0103] In a second embodiment, the support material a), in particular a fibrous material, prepared 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).

[0104] The application of the nanoporous layer in step ii) or step ii-b) can be carried out in various ways. Discontinuous production frequently uses spraying, screen printing, or Mayer rod methods, while continuous coating preferably uses doctor blade, slot die, and gravure roll processes. Here, the layer thickness of the nanoporous layer and the penetration depth of the coating agent into the carrier material can be influenced by the coating process parameters and the viscosity of the coating agent.

[0105] Finally, a heat treatment can be carried out, for example, in a drying oven and a sintering oven, where drying can be carried out first at a temperature of 100-200° C., followed by sintering at a temperature of 300-500° C. Preferably, the heat treatment in step ii) is carried out at a temperature at which the polymer binder is present in a partially or completely molten state.

[0106] A preferred embodiment is i1) providing a fiber composition containing carbon fibers and / or precursors of carbon fibers as a planar, gas-permeable carrier material; i2) subjecting the fiber composition prepared in step i1) to a method for producing a nonwoven fabric, i3) if the fiber composition used in step i1) comprises precursors of carbon fibers, subjecting the nonwoven fabric to pyrolysis at a temperature of at least 1000°C, ii) coating the nonwoven fabric obtained in step i2) or i3) with a nanoporous layer; It is a method.

[0107] Separation of gas mixtures For separation, the starting gas mixture can be passed through one or more membrane devices. Multiple membrane devices can be arranged in series or parallel with respect to the gas flow direction. A combination of membrane devices arranged in series and parallel is also possible. Furthermore, in the context of a recirculation circuit, the gas flow can be partially or completely returned to an upstream membrane device. The series connection of two or more membrane devices preferably serves to increase selectivity. The parallel connection preferably serves to increase throughput and allows for easier maintenance and / or replacement of membrane devices during operation.

[0108] The membrane device used for gas separation comprises a device for feeding the starting gas mixture and a device for withdrawing at least one gas stream obtained during gas separation.

[0109] A further subject of the present invention is a membrane device as defined above or obtainable by the method defined above. In this context, the term membrane device also includes a composition of two or more individual membrane devices used for gas separation.

[0110] A further subject of the present invention is a process for at least partially separating at least one gas component from a gas mixture, which process comprises subjecting a starting gas mixture to separation into at least one retentate stream and at least one permeate stream in at least one membrane separation stage, the membrane separation stage comprising at least one membrane device as defined above or obtainable by a process as defined above.

[0111] A further object of the present invention is to provide a process for selective gas separation, preferably for the selective separation of gas mixtures from large-scale industrial hydrogen production, in particular for the selective separation of hydrogen and at least one C1-C 14 Use of a membrane device as defined above or obtainable by a process as defined above for the selective separation of a gas mixture containing hydrocarbons, preferably at least one C1-C6 hydrocarbon.

[0112] The following examples are intended to illustrate the present invention without, however, limiting it thereto.

[0113] Example 1: Fabrication of membrane devices from carbon fiber nonwoven fabric as support material and nanoporous carbon-containing layers To produce the base nonwoven fabric, a dry-laid fiber web made of 100% oxidized polyacrylonitrile fibers was laid in a carding machine. The fiber web was sent to a consolidation unit, where the fibers were wound on both sides and intertwined with each other using high-energy water jets at a pressure of approximately 100 bar in the first stage and approximately 200 bar in the second stage. The nonwoven fabric was then subjected to thickness calibration, whereby the thickness of the water-consolidated nonwoven fabric was reduced to 0.25 mm. The nonwoven fabric was then sent to a carbonization unit where it was carbonized at approximately 1000-1400 °C under a nitrogen atmosphere. 65 g / m 2 A nonwoven fabric made of 100% carbon fiber with a basis weight of 100g / m2 was obtained. To treat the nonwoven fabric, an aqueous impregnation composition containing 70% carbon black and 30% polytetrafluoroethylene (PTFE) on a solids basis was mixed. The treatment was carried out at a treatment weight of 15% (10g / m2) based on the mass of the nonwoven fabric substrate.2 This was achieved by foulard impregnation with an aqueous dispersion having a surface area of ​​1000 nm (corresponding to 1000 nm). This was followed by further drying at 160°C for 5 minutes and sintering at 400°C for 10 minutes. The substrate thus obtained was then coated to produce a nanoporous surface layer. The composition of the coating for producing the nanoporous layer consisted of 2% PTFE, 2% PEEK, 0.11% surface-active additives, and 11% nanoporous carbon. The fibrous material was then dried at 160°C and sintered at 400°C. The resulting load with the nanoporous layer was 35 g / m 2 It was.

[0114] The achieved permeabilities and selectivities of the materials from Example 1 are listed in Table 1.

[0115] [Table 1]

[0116] Example 2: Fabrication of membrane devices from carbon fiber nonwovens as support materials, microporous layers, and nanoporous carbon-containing layers To produce the base nonwoven fabric, a dry-laid fiber web made of 100% oxidized polyacrylonitrile fibers was laid in a carding machine. The fiber web was sent to a consolidation unit, where the fibers were wound on both sides and entangled with each other using a high-energy water stream at a pressure of approximately 100 bar in the first stage and approximately 200 bar in the second stage. The nonwoven fabric was then subjected to thickness calibration, whereby the thickness of the water-stream-consolidated nonwoven fabric was reduced to 0.25 mm. The nonwoven fabric was then sent to a carbonization unit where it was carbonized at approximately 1000-1400 °C under a nitrogen atmosphere. 65 g / m 2 A nonwoven fabric made of 100% carbon fiber with a basis weight of 100g / m2 was obtained. To treat the nonwoven fabric, an aqueous impregnation composition containing 70% carbon black and 30% polytetrafluoroethylene (PTFE) on a solids basis was mixed. The treatment was carried out at a treatment weight of 15% (10g / m2) based on the mass of the nonwoven fabric substrate. 2This was done by foulard impregnation with an aqueous dispersion having a tensile strength equivalent to 10 ... 2 The microporous layer was then coated to produce a nanoporous layer. The composition of the coating for producing the nanoporous layer consisted of 2% PTFE, 2% PEEK, 11% nanoporous carbon, and 0.08% surface active additive in distilled water. The substrate was then dried at 160°C and sintered at 400°C. The resulting load with the nanoporous layer was 15 g / m 2 It was.

[0117] The achieved permeabilities and selectivities of the materials from Example 2 are listed in Table 2.

[0118] [Table 2]

Claims

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

2. a) a gas-permeable carrier material in the form of a surface; a / b) a microporous layer on at least one of the faces of the carrier material; b) a nanoporous carbon-containing layer on the microporous layer a / b), the nanoporous layer comprising at least one carbon component in a polymer binder, the nanoporous carbon-containing layer having an average pore size in the range of 0.3 to 2.0 nm and a pore size distribution in the range of 0.1 to 5.0 nm; 1. A membrane device for selective gas separation comprising:

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 to 1.5 nm, preferably 0.5 to 1.3 nm.

4. The membrane device according to any one of claims 1 to 3, wherein the nanoporous carbon-containing layer b) has a layer thickness in the range of 0.5 to 500 μm, preferably 1.0 to 10 μm.

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

6. 6. The membrane device according to claim 1, wherein the planar gas-permeable support material a) is selected from fibrous materials, porous metal supports, porous ceramic and non-ceramic supports, monolithic supports, gas-permeable polymer supports, and combinations thereof.

7. 7. The membrane device according to claim 1, wherein the carrier material a) comprises or consists of at least one planar fibrous material, the carrier material being preferably selected from nonwoven fabrics, woven fabrics, knitted fabrics, paper, and combinations thereof.

8. 8. The membrane device of claim 7, wherein the planar fiber material a) is selected from nonwoven carbon fiber fabric, woven carbon fiber fabric, carbon fiber paper, and combinations thereof.

9. 9. The membrane device according to claim 1, 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 from the production of the nanoporous carbon-containing layer b), and mixtures thereof.

10. 10. The membrane device according to claim 1, wherein the nanoporous carbon-containing layer b) comprises a polymer binder containing at least one fluorine-containing polymer b1) and / or at least one fluorine-free high-temperature resistant polymer b2).

11. 11. The membrane device of claim 10, wherein the nanoporous carbon-containing layer b) comprises a polymer binder containing at least one fluorine-containing polymer b1) selected from polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, perfluoroalkoxy polymer, and mixtures thereof.

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

13. 13. The membrane device according to claim 1, comprising a microporous layer a / b), wherein the average pore diameter of said microporous layer a / b) is 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. 14. The membrane device according to any one of claims 1 to 13, comprising a microporous layer a / b), said microporous layer a / b) being free from the addition of transition metal compounds.

15. 15. The membrane device according to any one of claims 1 to 14, comprising a microporous layer a / b), said microporous layer a / b) being free of added fibers, in particular free of added carbon fibers.

16. 16. The membrane device according to claim 1, further comprising a device for feeding a starting gas mixture and a device for withdrawing at least one gas stream obtained during gas separation.

17. 1. A method of manufacturing a membrane device, comprising: i) providing a gas-permeable carrier material a) in the form of a sheet; 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 in the range of 0.3 to 2 nm and a pore size distribution of 0.1 to 5.0 nm; method.

18. 1. A method of manufacturing a membrane device, comprising: i) providing a gas-permeable carrier material a) in the form of a sheet; 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, the pores having an average pore size in the range of 0.3 to 2 nm and a pore size distribution of 0.1 to 5.0 nm; method.

19. i1) providing a fiber composition containing carbon fibers and / or precursors of carbon fibers as a planar, gas-permeable carrier material; i2) subjecting the fiber composition prepared in step i1) to a method for producing a nonwoven fabric, i3) if the fiber composition used in step i1) comprises precursors of carbon fibers, subjecting the nonwoven fabric to pyrolysis at a temperature of at least 1000°C; ii) coating the nonwoven fabric obtained in step i2) or i3) with a nanoporous layer; 18. The method of claim 17.

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

21. 20. A process for at least partially separating at least one gas component from a gas mixture, comprising subjecting a starting gas mixture to separation into at least one retentate stream and at least one permeate stream in at least one membrane separation stage, said membrane separation stage comprising at least one membrane device as defined in any one of claims 1 to 16 or as obtained by a process as defined in any one of claims 17 to 19.

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

23. The starting gas mixture comprises hydrogen and at least one C １ ~C １４ Hydrocarbons, preferably CH ４ , C ２ H ６ , C ３ H ８ , and C ４ H １０ At least one C selected from １ ~C ６ 23. The method of claim 21 or 22, which contains a hydrocarbon.

24. The starting gas mixture is preferably CO, CO ２ , N ２ 24. The method of claim 23, further comprising at least one additional gas component selected from:

25. For selective gas separation, preferably for selective separation of gas mixtures from large-scale industrial hydrogen production, in particular hydrogen and at least one C １ ~C １４ Hydrocarbons, preferably at least one C １ ~C ６ 20. Use of a membrane device as defined in any one of claims 1 to 16 or obtained by the process as defined in any one of claims 17 to 19 for the selective separation of gas mixtures containing hydrocarbons.

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