Gas separation membrane and gas separation system using the same

Abstract

This improves the permeability of small molecular gases such as hydrogen, helium, water vapor, and ammonia, as well as their separation selectivity from other gases such as oxygen, nitrogen, and methane. [Solution] A gas separation membrane having at least a separation functional layer and a sheet layer.

Description

[Technical Field]

[0001] The present invention relates to a gas separation membrane capable of selectively separating at least one component from a gaseous mixture, and a gas separation system using the same. [Background technology]

[0002] In recent years, hydrogen has attracted attention as a clean energy source. Hydrogen is obtained by reforming and gasifying fossil fuels such as natural gas and coal, and removing unwanted gases from the resulting gas mixture, which mainly consists of hydrogen and carbon dioxide. It can also be obtained by decomposing water using electricity or photocatalysis, and extracting only hydrogen from the gas mixture containing hydrogen, oxygen, and water vapor. Hydrogen is also used in the Haber-Bosch process to synthesize ammonia. This method synthesizes ammonia by reacting hydrogen and nitrogen at high temperature and pressure, but a process is required in the production plant to separate and recover unreacted hydrogen and nitrogen.

[0003] As a low-cost method for concentrating a specific gas from a gas mixture, membrane separation, which selectively permeates the target gas by utilizing the differences in gas permeability of different materials, is attracting attention.

[0004] Patent Document 1 proposes a method for improving the selective separation of gases by attaching a surfactant to a single-layer hollow fiber membrane. Non-Patent Document 1 describes a technique for improving the selective separation of helium and carbon dioxide by coating the surface of a polyamide membrane with polyphenylene oxide. Non-Patent Document 2 describes a method for improving the selective separation of methane and other gases by coating the surface of an RO membrane with polydimethylsiloxane. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 3-186327 [Non-patent literature]

[0006]

Non-Patent Document 1

Non-Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, in the conventional technology, it is impossible to efficiently increase the permeation resistance with other gases such as oxygen, nitrogen, and methane, and there is a problem that it is impossible to achieve both high permeability of gases with small molecular diameters such as hydrogen, helium, water vapor, and ammonia and high selective separation with other gases such as oxygen, nitrogen, and methane.

[0008] In addition, among gases with small molecular diameters, for example, separating hydrogen and water vapor has the problem that separation by molecular sieves is difficult.

[0009] Therefore, the present invention has been made in view of the above conventional situation, and an object thereof is to provide a gas separation membrane having high permeability of gases with small molecular diameters such as hydrogen, helium, water vapor, and ammonia and high selective separation with other gases such as oxygen, nitrogen, and methane, a composite module for gas separation using the same, a gas separation system, and a method for purifying helium (He) or hydrogen (H2).

Means for Solving the Problems

[0010] As a result of intensive studies by the present inventors to solve the above problems, the performance of the gas separation membrane, particularly the selective separation property, has been significantly improved. The present invention has the following gist.

[0011] (1) A gas separation membrane having at least a separation functional layer and a sheet layer.

[0012] (2) The gas separation membrane according to (1), having a coating layer on the separation functional layer.

[0013] (3) The gas separation membrane according to (1) or (2), wherein the sheet layer has a plurality of sheet layers.

[0014] (4) The water vapor permeability of the sheet layer is 0.001 to 100 nmol / m 2 A gas separation membrane as described in (1) to (3), having a pressure of / s / Pa.

[0015] (5) The gas separation membrane according to (1) to (4), wherein the main component of the separation functional layer is a crosslinked aromatic polyamide.

[0016] (6) The gas separation membrane according to (1) to (5), wherein the thickness of the sheet layer is 20 μm or more and 3000 μm or less.

[0017] (7) The gas separation membrane according to (1) to (6), wherein the sheet layer comprises at least one substance selected from the group consisting of polyolefin, fluororesin, polystyrene, silicone, microporous polymer (PIM), phenolic resin, urethane resin, aluminum, silica, chromium, copper, gold, titanium, and palladium.

[0018] (8) A method for producing a gas separation membrane, comprising the step of pressurizing the gas separation membrane described in (1) to (7) at a pressure of 0.1 MPa or more and 10 MPa or less.

[0019] (9) The gas separation membrane according to (1) to (8), characterized in that it is used in at least one step selected from the following: separation of gases in the manufacturing process of optical fibers, semiconductors, and electrical products; separation of gases produced in the reaction of natural gas, city gas, biogas, and methanation, separation of gases containing unreacted raw materials and by-products; separation of gases generated from water electrolysis equipment; and separation of gases to concentrate a target gas from a mixed gas.

[0020] A method for manufacturing optical fibers, characterized by using a gas separation membrane as described in (1) to (8).

[0021] A method for manufacturing semiconductors, characterized by using a gas separation membrane as described in (1) to (8).

[0022] (12) A method for manufacturing an electrical product, characterized by using a gas separation membrane as described in (1) to (8).

[0023] A method for producing a gas, characterized by using a gas separation membrane as described in (1) to (8), for separating at least one gas selected from natural gas, city gas, biogas, gases produced in methanation reactions, gases containing unreacted raw materials and by-products, gases from fermentation or enzymatic reaction processes, and gases generated from water electrolysis equipment.

[0024] (14) An optical fiber characterized by being manufactured using a gas separation membrane as described in (1) to (8).

[0025] A semiconductor characterized by being manufactured using the gas separation membrane described in (1)(1) to (8) (15)(

[0026] (16) An electrical product characterized by being manufactured using a gas separation membrane as described in (1) to (8).

[0027] A gas separation apparatus characterized by using the gas separation membranes described in (1) to (8) above, for separating at least one gas selected from natural gas, city gas, biogas, gases produced in methanation reactions, gases containing unreacted raw materials and by-products, gases from fermentation and enzymatic reaction processes, and gases generated from water electrolysis equipment.

[0028] (18) A spiral-type gas separation membrane module in which the gas separation membrane described in (1) to (8), the supply-side flow channel material and the permeate-side flow channel material are wound around a central tube.

[0029] A gas separation system comprising the spiral-type gas separation membrane module described in (19)(18).

[0030] A method for purifying He or H2 using the gas separation system described in (20)(19). [Effects of the Invention]

[0031] According to the present invention, it is possible to provide a gas separation membrane, a spiral-type gas separation membrane module, and a gas separation system using the same, which have high selective separation capabilities for gases with small molecular sizes such as hydrogen, helium, water vapor, and ammonia. [Brief explanation of the drawing]

[0032] [Figure 1] This is a cross-sectional view of a gas separation membrane according to one embodiment of the present invention. [Figure 2] This is a cross-sectional view of a gas separation membrane according to one embodiment of the present invention. [Figure 3] This is a perspective view showing a partially disassembled spiral-type gas separation membrane module. [Modes for carrying out the invention]

[0033] 1. Gas separation membrane The gas separation membrane of the present invention is a gas separation membrane having at least a separation functional layer and a sheet layer. The gas separation membrane of the present invention will be described in detail below.

[0034] As shown in Figure 1, the gas separation membrane (51) of this embodiment comprises at least a separation functional layer (53) and a sheet layer (54). It may also have a porous support layer (52) and a substrate (55).

[0035] (base material) The gas separation membrane of the present invention may have a substrate. The substrate does not need to have selective permeability for gas separation; it is sufficient that it can provide strength to the entire gas separation membrane by supporting the separation functional layer.

[0036] The resin constituting the base material is not particularly limited, but examples include polyester polymers, polyamide polymers, polyolefin polymers, polysulfide polymers, or mixtures and copolymers thereof. Among these, polyester polymers and polysulfide polymers, which have high mechanical strength and thermal stability, are particularly preferred as the resin constituting the base material.

[0037] The form of the substrate is not particularly limited, but nonwoven fabrics or woven / knitted fabrics such as long-fiber nonwoven fabrics and short-fiber nonwoven fabrics are preferred, and the use of long-fiber nonwoven fabrics is particularly preferred. Here, long-fiber nonwoven fabric refers to a nonwoven fabric with an average fiber length of 300 mm or more and an average fiber diameter of 3 to 30 μm. By using long-fiber nonwoven fabric, the polymer solution that will form the porous support layer can be sufficiently impregnated, thereby improving adhesion to the substrate and enhancing the physical stability of the porous support film. In addition, sufficient impregnation of the polymer solution into the substrate increases the substitution rate with the non-solvent during phase separation that forms the porous support layer. As a result, the generation of macrovoids can be suppressed, contributing to improved gas permeability selectivity.

[0038] (porous support layer) The gas separation membrane of the present invention may have a porous support layer. The porous support layer only needs to be permeable to hydrogen or helium. The porous support layer only needs to be able to provide strength to the entire gas separation membrane by supporting the separation functional layer. It may or may not have selective permeability for gas separation, but having selective permeability is more preferable because it can improve the selectivity of the gas separation membrane.

[0039] The size and distribution of pores in the porous support layer are not particularly limited, but for example, the pore diameter may be uniform throughout the porous support layer, or it may gradually increase from the surface in contact with the separation functional layer to the other surface in the porous support layer.

[0040] The material of the porous support layer is not particularly limited, but examples include homopolymers or copolymers such as polysulfone, polyethersulfone, polyamide, polyaramid, polyester, cellulose polymers, vinyl polymers, polyphenylene sulfide, polyphenylene sulfide sulfone, polyphenylene sulfone, and polyphenylene oxide, which can be used alone or in mixtures. Examples of cellulose polymers include cellulose acetate and cellulose nitrate, and examples of vinyl polymers include polyethylene, polypropylene, polyvinyl chloride, and polyacrylonitrile.

[0041] Among these, homopolymers or copolymers such as polysulfone, polyamide, polyester, cellulose acetate, cellulose nitrate, polyvinyl chloride, polyacrylonitrile, polyphenylene sulfide, and polyphenylene sulfide sulfone are preferred as materials for the porous support layer. Cellulose acetate, polysulfone, polyphenylene sulfide sulfone, or polyphenylene sulfone are more preferred due to their high chemical, mechanical, and thermal stability, with polysulfone and cellulose acetate being particularly preferred.

[0042] The thickness of the substrate and the porous support layer affects the strength of the composite semipermeable membrane and the packing density when it is used as an element. From the viewpoint of obtaining good mechanical strength and packing density, the total thickness of the substrate and the porous support layer is preferably 30 to 300 μm, and more preferably 100 to 220 μm. The thickness of the porous support layer is preferably 20 to 100 μm, more preferably 23 μm to 50 μm, and even more preferably 27 μm to 40 μm. The thickness of the substrate and the porous support layer can be determined by calculating the average value of 20 thicknesses measured at 20 μm intervals in a direction perpendicular to the thickness direction (the surface direction of the membrane) during cross-sectional observation. If it is difficult to observe the thickness of the substrate or the composite semipermeable membrane under a microscope, it may be measured using a thickness gauge. The thickness of the separation function layer is very thin and negligible compared to the thickness of the porous support layer, so the thickness of a structure in which the separation function layer is placed on top of the porous support layer can be considered as the thickness of the porous support layer. Therefore, the thickness of the porous support layer can be calculated by measuring the thickness of the composite semipermeable membrane with a digital thickness gauge and subtracting the thickness of the substrate from the thickness of the composite semipermeable membrane. Examples of digital thickness gauges that can be used include the PEACOCK from Ozaki Seisakusho Co., Ltd.

[0043] (separation functional layer) The material of the separation functional layer in the gas separation membrane of the present invention is not particularly limited. Examples include rubbery polymer materials such as silicone resin and polybutadiene resin, polymer membranes such as cellulose acetate, polysulfone, aromatic polyamide, polyethersulfone, polyacrylonitrile, polyphenylene sulfide, polyetheretherketone, polytetrafluoroethylene, and polyvinylidene fluoride, inorganic membranes containing metals such as zeolite, silica, and palladium, and metal-organic structures such as MOFs (Metal Organic Frameworks). The separation membrane may be any of the following: a homogeneous membrane, an asymmetric membrane consisting of a homogeneous layer and a porous layer, or a microporous membrane. It is preferable to use cellulose, polyimide, or polyamide, and a composite film having a separation functional layer containing polyamide is preferred. When the separation functional layer is mainly composed of polyamide, it can be formed by interfacial polycondensation of a polyfunctional amine and a polyfunctional acid halide on a porous support layer.

[0044] Having polyamide as the main component means that in 100% by weight of the separation functional layer, polyamide accounts for 50% or more by weight, and the amount of polyamide in 100% by weight of the separation functional layer is preferably 80% or more by weight, and more preferably 90% or more by weight and 100% or less by weight.

[0045] The polyamide in the separation functional layer may be a fully aromatic polyamide, a fully aliphatic polyamide, or a polyamide containing both aromatic and aliphatic parts; however, to achieve higher performance, it is preferable to be fully aromatic.

[0046] Polyfunctional amines specifically refer to polyfunctional aromatic amines or polyfunctional aliphatic amines. A polyfunctional aromatic amine is an aromatic amine that has two or more amino groups selected from primary and secondary amino groups in one molecule, and at least one of these amino groups is a primary amino group. A polyfunctional aliphatic amine is an aliphatic amine that has two or more amino groups selected from primary and secondary amino groups in one molecule.

[0047] For example, polyfunctional aromatic amines include o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, o-xylylenediamine, m-xylylenediamine, p-xylylenediamine, o-diaminopyridine, m-diaminopyridine, and p-diaminopyridine, in which two amino groups are bonded to the aromatic ring in an ortho, meta, or para position.

[0048] Examples of polyfunctional aliphatic amines include ethylenediamine, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, piperazine, 2-methylpiperazine, 2,4-dimethylpiperazine, 2,5-dimethylpiperazine, and 2,6-dimethylpiperazine. These polyfunctional amines may be used individually or in combination of two or more.

[0049] Furthermore, polyfunctional acid halides specifically refer to polyfunctional aromatic acid halides or polyfunctional aliphatic acid halides.

[0050] A polyfunctional acid halide is an acid halide having at least two halogenated carbonyl groups in one molecule. For example, trifunctional acid halides include trimesic acid chloride, and difunctional acid halides include biphenyldicarboxylic acid dichloride, azobenzenedicarboxylic acid dichloride, terephthalic acid chloride, and isophthalic acid chloride.

[0051] Considering the reactivity with polyfunctional amines, polyfunctional acid halides are preferably polyfunctional acid chlorides. Furthermore, considering the selective separation and heat resistance of gas separation membranes, polyfunctional acid chlorides having 2 to 4 carbonyl chloride groups in a single molecule are preferable.

[0052] Among these, trimesic acid chloride is more preferred from the standpoint of ease of availability and handling. These polyfunctional acid halides may be used individually or in combination of two or more.

[0053] Furthermore, polycondensation reactions specifically refer to interfacial polycondensation.

[0054] The separation functional layer of the present invention preferably uses a crosslinked aromatic polyamide as its main component in order to exhibit higher performance. The crosslinked aromatic polyamide can be formed by interfacial polycondensation between a polyfunctional aromatic amine and a polyfunctional aromatic acid halide.

[0055] In the separation functional layer, the thin film may have a pleated structure having recesses and protrusions. When a pleated structure is present, the surface area of ​​the film that has the separation function increases relative to the film area, thereby increasing the gas permeability.

[0056] (covering layer) The gas separation membrane of the present invention may have a coating layer on the separation functional layer. The coating layer does not necessarily have to cover the entire surface of the separation membrane; in some cases, the coating layer may be partially missing due to uneven coating during its formation, or the coating layer may be formed only on surfaces with particularly large pores or defects.

[0057] As the coating layer, materials commonly used in the relevant art can be used without particular limitations. For example, organic materials such as silicone resins, polyolefin resins, polyvinyl alcohol, and polyurethanes, as well as metal-organic structures such as MOFs (Metal Organic Frameworks) and metallic materials such as palladium or palladium alloys, which are hydrogen permeable materials, can be used. From the standpoint of being readily available and easy to handle, silicone-based materials are preferred.

[0058] When a coating layer is present, the process generally involves forming the separation functional layer followed by a further coating step. In the case of flat films, coating can be done using a bar coater or spin coating. For continuous coating, gravure, slot die, roll, spray, and dip coating methods are preferably used. The method can be selected based on the thickness of the coating layer, the viscosity of the coating solution used, and the coating speed.

[0059] The thickness of the coating layer is preferably 0.01 μm to 10 μm, more preferably 0.1 μm to 2 μm, and even more preferably 0.2 μm to 1.0 μm. A thickness of 0.01 μm or more prevents defects in the coating layer caused by irregularities in the separation functional layer and uneven coating thickness. A thickness of 10 μm or less minimizes the reduction in gas permeability due to the coating layer, while maintaining high gas permeability.

[0060] The thickness of the coating layer can be determined by observing a cross-section of the gas separation membrane using a scanning electron microscope and performing image analysis on the resulting cross-sectional image. The freeze-fracture method is used to prepare the observation sample. Specifically, this involves freezing the sample using a refrigerant such as liquid nitrogen and then exposing the cross-section using a razor blade or microtome. Image analysis software such as ImageJ or Mac-View can be used for image analysis. The average pore diameter Rc [nm] of the coating layer is not particularly limited as long as it reduces the pore size of the separation functional layer by covering large pores and defects in the separation functional layer, or has permeation resistance and thus provides separation functionality. However, it is preferably 0.3 nm to 1.0 nm, more preferably 0.31 nm to 0.8 nm, and even more preferably 0.32 nm to 0.70 nm. An average pore diameter Rc [nm] of the coating layer of 0.3 nm or more makes it possible to maintain as much permeation as possible of small molecular gases such as hydrogen, helium, water vapor, and ammonia, while setting it to 1.0 nm or less effectively suppresses the permeation of oxygen, nitrogen, methane, etc. caused by large pores and defects in the separation functional layer.

[0061] (Sheet layer) The gas separation membrane of the present invention has a separation functional layer and a sheet layer. The separation functional layer has a small area with large pores and defects, resulting in significantly high gas permeability. In such areas, the contribution of separation by molecular sieving is small, and the selective separation performance for gases with small molecular sizes, such as hydrogen, helium, water vapor, and ammonia, is low. Reducing the contribution of areas with low selective separation performance, such as large pores and defects, is important for improving the selective separation performance of the entire membrane.

[0062] The gas separation membrane of the present invention preferably has an average pore diameter Rc [nm] of the sheet layer formed by the positron beam method of 0.6 nm or more and 1.5 nm or less, more preferably 0.7 nm or more and 1.2 nm or less, and even more preferably 0.8 nm or more and 1.0 nm or less. By having an average pore diameter Rc [nm] of 0.6 nm or more in the sheet layer, it is possible to maintain as much permeability as possible for gases with small molecular sizes such as hydrogen, helium, water vapor, and ammonia, and by having it be 1.5 nm or less, it is possible to effectively suppress the permeability of oxygen, nitrogen, methane, etc. caused by large pores and defects in the functional layer.

[0063] The positron beam method is a positron annihilation lifetime measurement method that measures the time it takes for a positron to annihilate a sample after it is incident on it. From this annihilation time, it non-destructively evaluates information regarding the size, number density, and distribution of vacancies of approximately 0.1 to 10 nm. Unlike conventional positron annihilation methods, it uses a positron beam instead of a radioactive isotope (22Na) as the positron source, making it possible to measure thin films with a thickness of several hundred nanometers. The average vacancy diameter Rc [nm] of the coating layer is determined from the positron annihilation lifetime τ when a positron is fired at an intensity of 1 keV from the surface with the coating layer.

[0064] The average vacancy diameter Rc [nm] of the coating layer of the gas separation membrane of the present invention is determined from the following Equation 1 based on the positron annihilation lifetime τ described above. Equation 1 shows the relationship assuming that orthopositronium (o-Ps) exists in vacancies of average vacancy diameter Rc in an electron layer of thickness ΔR, and ΔR has been empirically determined to be 0.166 nm (details are described in Nakanishi et al., Journal of Polymer Science, Part B: Polymer Physics, Vol.27, p.1419, John Wiley & Sons, Inc. (1989)).

[0065]

number

[0066] The sheet layer does not necessarily need to cover the entire surface of the separation functional layer. In some cases, the sheet layer may be partially missing due to uneven coating during its formation, or it may be formed only on surfaces with a particularly high number of large pores or defects.

[0067] There are no particular restrictions on the position of the sheet layer in the gas separation membrane of the present invention. The position of the sheet layer can be determined according to its purpose. The separation functional layer can suppress gas permeation through coarse pores and defects. The sheet layer significantly suppresses the permeation of oxygen, nitrogen, methane, etc., but has little effect on the permeation of gases with small molecular sizes such as hydrogen and helium, thus greatly improving selective separation. Forming the sheet layer on top of the separation functional layer is preferable because it can directly cover coarse pores and defects.

[0068] If the gas separation membrane of the present invention has a separation functional layer, a coating layer, and a sheet layer, the coating layer directly covers coarse pores and defects, and the sheet layer has a difference in permeability between the gas to be separated and other gases, thereby greatly improving selective separation performance, and selective separation of a specific gas may be performed by the sheet layer.

[0069] For example, if the supplied gas has humidity and contains water vapor, it is preferable to select a sheet layer that is less permeable to water vapor. In gas membrane separation, if the permeation side is depressurized with a vacuum pump and that vacuum pump is of the scroll or diaphragm type, there is a concern that water vapor may condense as the vacuum pump exhausts the depressurized gas to atmospheric pressure. In such cases, the efficiency of the vacuum pump may decrease, and in some cases, rust may form, potentially affecting the maintenance cycle and lifespan of the vacuum pump.

[0070] Furthermore, if the supply gas contains humidity, especially with inorganic separation membranes, there is a concern that moisture may condense in the pores of the separation membrane due to capillary action, leading to a decrease in the membrane's performance.

[0071] Therefore, it is preferable that the sheet layer allows as little water permeation as possible. In such a case, the sheet layer is preferably disposed at the very beginning of gas permeation and on the supply gas side.

[0072] The gas separation membrane of the present invention may have a plurality of sheet layers. Each sheet layer can selectively separate a specific substance. For example, starting from the supply gas side, fine powder can be captured by the first sheet layer such as non-woven fabric, the second sheet layer such as aluminum vapor deposition can reduce the permeation of water vapor, and the separation functional layer can separate the gas. Another example is that the first sheet layer such as aluminum vapor deposition reduces the permeation of water vapor, the second zeolite-based sheet layer adsorbs and reduces the remaining moisture and hydrogen sulfide, and the separation functional layer separates the gas.

[0073] Also, the first sheet layer such as aluminum vapor deposition reduces the permeation of water vapor, the separation functional layer separates the gas, and the sheet layer 3 provided on the opposite side of the separation functional layer of the next gas separation membrane can adsorb and remove trace components such as the remaining moisture.

[0074] The water vapor permeability of the sheet layer is preferably 0.001 nmol / m 2 / s / Pa or more and 100 nmol / m 2 / s / Pa or less. Further, it is preferably 0.01 nmol / m 2 / s / Pa or more and 50 nmol / m 2 / s / Pa or less, and particularly preferably 0.1 nmol / m 2 / s / Pa or more and 10 nmol / m 2 / s / Pa or less. When the water vapor permeability is 0.001 nmol / m 2 / s / Pa or more, water can be separated between the non-permeation side and the permeation side. When the water vapor permeability is 100 nmol / m 2 / s / Pa or less, the permeability for gases such as helium and hydrogen, which have a dynamic molecular diameter similar to that of water, can be ensured, and efficient separation can be achieved.

[0075] As described above, by providing a sheet layer, it is possible to prevent performance degradation such as a reduction in separation selectivity of the separation functional layer of the gas separation membrane.

[0076] To construct a sheet layer, for example, one can simply stack sheet layers on top of the separation functional layer of a gas separation membrane, which is easier than creating a coating layer.

[0077] In the gas separation membrane of the present invention, the adhesion strength between the separation functional layer and the sheet layer, and between the coating layer and the sheet layer, is preferably 0.1 N / 25 mm or more and 10 N / 25 mm or less, more preferably 0.3 N / 25 mm or more and 3 N / 25 mm or less, and even more preferably 0.5 N / 25 mm or more and 2 N / 25 mm or less.

[0078] By achieving an adhesion strength of 0.1 N / 25 mm or higher between the separation functional layer and the sheet layer, the permeation of oxygen, nitrogen, methane, etc., caused by large pores or defects in the functional layer can be effectively suppressed. By achieving an adhesion strength of 5 N / 25 mm or lower, delamination between the porous support layer and the substrate can be suppressed, making it possible to replace and reuse the sheet. This offers superior replaceability and recyclability compared to coating, and because production is easier, production costs and equipment costs can be reduced.

[0079] Furthermore, especially in the case of flat membranes, if the adhesion strength between the separation functional layer and the sheet layer, and between the coating layer and the sheet layer is low, there is a concern that the supplied gas or gas that has permeated through each layer may leak from between the layers.

[0080] To reduce gas leakage between layers, in a flat membrane system, adhesive or heat sealing may be used at the points separating the supply gas / impermeable gas from the permeable gas between layers. Although this reduces the membrane area, it can improve separation selectivity by reducing concerns about leakage.

[0081] Materials that can form the sheet layer include polyolefins, polyvinyl alcohol, fluororesins, polystyrene, silicones, microporous polymers (PIMs), phenolic resins, urethane resins, metal-organic frameworks (MOFs), aluminum, silica, chromium, copper, gold, titanium, and metallic materials such as palladium or palladium alloys, which are hydrogen permeable materials. From the viewpoint of availability and ease of handling, polysiloxanes are preferred.

[0082] The thickness of the sheet layer is preferably 20 μm to 3000 μm, more preferably 30 μm to 1000 μm, and even more preferably 5 μm to 500 μm. A thickness of 20 μm or more allows for maximum permeability of small molecular gases such as hydrogen, helium, water vapor, and ammonia, while simultaneously preventing deformation such as curling of the sheet layer. A sheet layer thickness of 3000 μm or less effectively suppresses the permeability of oxygen, nitrogen, methane, etc., caused by large pores or defects in the functional layer.

[0083] The thickness of the sheet layer can be measured, for example, using a dial thickness gauge or a digital thickness gauge. Products such as PEACOCK from Ozaki Seisakusho Co., Ltd. and Teclock Co., Ltd. can be used as dial thickness gauges or digital thickness gauges. When using a dial thickness gauge or digital thickness gauge, the thickness is measured at any 20 locations, and the arithmetic mean is calculated to determine the thickness of the sheet layer.

[0084] Alternatively, after freezing with liquid nitrogen, the cross-section was exposed using a razor blade. The thickness of the exposed gas separation membrane can also be measured by observing the cross-section at a magnification of 10,000x or more using a scanning electron microscope (such as the Hitachi High-Technologies S-5500). In this case, the area to be observed is from the surface layer to the porous support layer of the gas separation membrane. Before observation with the SEM, the membrane was coated with platinum-palladium. The thickness can also be obtained by binarizing the obtained cross-sectional image with ImageJ and performing image analysis. Specifically, a threshold can be applied to the cross-sectional image with ImageJ, the continuous black layer from the surface of the gas separation membrane can be considered as the coating layer, the thickness of the coating layer can be measured at three locations: the center, right edge, and left edge of the image, and the thickness of the coating layer in the obtained cross-sectional image can be calculated by taking the arithmetic mean of the three measurements.

[0085] 2. Method for manufacturing gas separation membranes Next, the method for manufacturing the gas separation membrane described above will be explained with an example.

[0086] (Formation of a supporting membrane) The laminate of the substrate and the porous support layer is referred to as the support film, and this case will be explained below. In the example given below, the method for forming the support film includes the steps of preparing a polymer solution by dissolving the polymer, which is a component of the porous support layer, in a suitable solvent for that polymer; applying the polymer solution to the substrate; and wet solidifying the polymer by immersing the polymer solution in a solidification bath. The solidified polymer corresponds to the porous support layer.

[0087] When using at least one of polysulfone or polyethersulfone as the polymer, the polymer solution is obtained by dissolving it in N,N-dimethylformamide (DMF). Water is preferably used as the coagulation bath.

[0088] Aramids, an example of polymers, can be obtained by solution polymerization or interfacial polymerization using acid chlorides and diamines as monomers. In solution polymerization, aprotic organic polar solvents such as N-dimethylformamide (DMF), N-methylpyrrolidone (NMP), and dimethylacetamide (DMAc) can be used as solvents. When polyamides are produced using acid chlorides and diamines as monomers, hydrogen chloride is produced as a by-product. To neutralize hydrogen chloride, inorganic neutralizing agents such as calcium hydroxide, calcium carbonate, and lithium carbonate, or organic neutralizing agents such as ethylene oxide, propylene oxide, ammonia, triethylamine, triethanolamine, and diethanolamine can be used.

[0089] (Formation of a separation functional layer) Next, the process of forming the separation functional layer will be explained. Below, we will describe a separation functional layer made of polyamide, which is an example of a separation functional layer. The separation functional layer made of polyamide is formed by forming polyamide on the support film through interfacial polycondensation between a polyfunctional amine and a polyfunctional acid halide.

[0090] More specifically, the process of forming the separation functional layer comprises the following steps. (a) A step of applying an aqueous solution containing a polyfunctional amine onto a porous support layer. (b) A step of applying an organic solvent solution containing a polyfunctional acid halide to the porous support layer after step (a).

[0091] In step (a), the concentration of the polyfunctional amine in the aqueous solution of the polyfunctional amine is preferably in the range of 0.1% by weight or more and 20% by weight or less, and more preferably in the range of 0.5% by weight or more and 15% by weight or less. When the concentration of the polyfunctional amine is in this range, sufficient selective separation and gas permeability can be obtained.

[0092] The polyfunctional amine aqueous solution may contain surfactants, organic solvents, alkaline compounds, antioxidants, etc., as long as they do not interfere with the reaction between the polyfunctional amine and the polyfunctional acid halide. Surfactants have the effect of improving the wettability of the support film surface and reducing the interfacial tension between the polyfunctional amine aqueous solution and the nonpolar solvent.

[0093] The application of the polyfunctional amine aqueous solution to the porous support layer is preferably carried out uniformly and continuously on the porous support layer. Application refers to bringing the polyfunctional amine aqueous solution into contact with the porous support layer, and specifically, this includes coating the surface of the porous support layer with the polyfunctional amine aqueous solution, or immersing the support film in the polyfunctional amine aqueous solution. Coating methods include dropping, spraying, and roller application.

[0094] The time between applying the polyfunctional amine aqueous solution onto the porous support layer and draining the liquid or applying the polyfunctional acid halide (i.e., the contact time between the porous support layer and the polyfunctional amine aqueous solution) is preferably 1 second or more and 10 minutes or less, and more preferably 10 seconds or more and 3 minutes or less.

[0095] After coating the porous support layer with a polyfunctional amine aqueous solution, the liquid must be removed to ensure no droplets remain on the layer. Remaining droplets can create film defects that reduce separation performance, but this can be prevented by removing the liquid. Methods for removing excess liquid include vertically gripping the support film after coating with the polyfunctional amine aqueous solution to allow it to flow naturally, or forcibly removing the liquid by blowing a stream of air, such as nitrogen, from an air nozzle.

[0096] In step (b), the concentration of the polyfunctional acid halide in the organic solvent solution is preferably in the range of 0.01% by weight or more and 10% by weight or less, and more preferably in the range of 0.02% by weight or more and 2.0% by weight or less. This is because a sufficient reaction rate can be obtained by setting it to 0.01% by weight or more, and the occurrence of side reactions can be suppressed by setting it to 10% by weight or less.

[0097] The organic solvent should preferably be immiscible with water, dissolve the polyfunctional acid halide without damaging the support film, and be inert to the polyfunctional amine compound and the polyfunctional acid halide. Preferred examples include hydrocarbon compounds such as n-hexane, n-octane, n-nonane, n-decane, n-undecane, n-dodecane, n-tridecane, isooctane, isodecane, and isododecane, or mixtures thereof.

[0098] The method for applying a polyfunctional acid halide solution to a porous support layer is the same as the method for applying a polyfunctional amine aqueous solution to a porous support layer. However, since it is preferable to apply the polyfunctional acid halide solution to only one side of the porous support layer, coating is preferable to immersion.

[0099] At this time, the porous support layer in contact with the organic solvent solution of the polyfunctional acid halide may be heated. The heating temperature is 50°C to 180°C, preferably 60°C to 160°C. Heating at 60°C or higher can compensate for the decrease in reactivity due to monomer consumption in the interfacial polymerization reaction with the reaction-accelerating effect of heat. Heating at 160°C or lower can prevent the solvent from completely volatilizing and significantly reducing the reaction efficiency. Furthermore, the heating time for each period is preferably 5 seconds to 600 seconds. A heating time of 5 seconds or more can be obtained to accelerate the reaction, and a heating time of 600 seconds or less can prevent the solvent from completely volatilizing.

[0100] Alternatively, a polyfunctional halide may be added during the interfacial polycondensation reaction to accelerate the consumption of the polyfunctional amine.

[0101] (Formation of the sheet layer) Next, we will explain the sheet layer formation process.

[0102] Sheet layers can be prepared by purchasing and using commercially available sheets, or by applying a solution or emulsion containing the material that forms the sheet layer to a polypropylene board or polyethylene board. The application method for preparing the sheet layer is not particularly limited, but it is preferable to apply the solution or emulsion containing the material that forms the sheet layer using a bar coater because the thickness of the sheet layer can be easily controlled.

[0103] Examples of solvents for solutions or emulsions containing the substance that forms the sheet layer include water, alcohols such as ethanol, 2-butanol, and isopropanol, alkanes such as pentane, hexane, heptane, octane, nonane, decane, and dodecane, benzene, toluene, and chloroform.

[0104] As mentioned above, the materials used to form the sheet layer include polyolefins, polyvinyl alcohol, fluororesins, polystyrene, silicones, microporous polymers (PIMs), phenolic resins, and urethane resins. From the viewpoint of ease of material availability and handling, it is preferable to use polysiloxane as the main component. Examples of such reagents include methyltris(methylethylketoxime)silane, vinyltris(methylethylketoxime)silane, aminoethylaminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, octamethylcyclotetrasiloxane, cyclic siloxane esters, and polydimethylsiloxane. Alternatively, polymers obtained by polymerizing one type of monomer, polymers obtained by polymerizing two or more types of monomers, or solutions containing commercially available admixtures may be brought into contact with the material. For example, the TSE series from Momentive Performance Materials, and silicone resins, silicone oligomers, and silicone emulsions from Shin-Etsu Silicone Co., Ltd. may be used.

[0105] Preferably, the sheet layer is adhered to the separation function layer. As long as they are adhered, the method of adhesion is not particularly limited, but examples include attaching the sheet layer and the separation function layer without generating air bubbles or wrinkles, and then pressing the sheet layer side with a roller or hydraulic press, or pressurizing in a pressure cell, bonding both ends between the separation function layer and the sheet layer with hot melt or chemical adhesive, or pressurizing in a pressure vessel with a gas such as oxygen or nitrogen.

[0106] The pressure applied is 0.05 MPa to 15 MPa, preferably 0.1 MPa to 10 MPa, more preferably 0.5 MPa to 7 MPa, and particularly preferably 1 MPa to 5 MPa. Applying pressure of 0.05 MPa or higher increases the adhesive strength between the sheet layer and the separation functional layer, effectively suppressing the permeation of oxygen, nitrogen, methane, etc., caused by large pores or defects in the separation functional layer. Applying pressure of 15 MPa or lower suppresses the occurrence of defects in the sheet layer and separation functional layer due to pressurization. The adhesive strength tends to increase with increasing pressure and varies depending on the material forming the sheet layer.

[0107] 3. Spiral-type gas separation membrane module (overview) The gas separation membrane of the present invention can be applied to spiral-type modules and stack-type modules when it takes the shape of a flat membrane, and to hollow-fiber modules when it takes the shape of a hollow fiber, but the spiral-type module will be described below.

[0108] The spiral-type gas separation membrane module of the present invention is a gas separation membrane module in which the aforementioned gas separation membrane, supply-side flow channel material, and permeate-side flow channel material are wound around a central tube that collects permeate gas, and its details will be described below.

[0109] Figure 3 is a perspective view showing a partially disassembled spiral-type gas separation membrane module (50). As shown in Figure 3, the spiral-type gas separation membrane module (50) comprises a central tube (100), a gas separation membrane (51), a supply-side flow channel material (101), and a permeate-side flow channel material (102).

[0110] (central canal) The central tube (100) is a hollow cylindrical member with through holes formed on its sides. The material of the central tube (100) does not need to be one that deteriorates depending on the pressure, temperature, or type of supplied gas when the module is in use. In Figure 3, G1 represents the supplied gas, G2 represents the permeate gas, and G3 represents the concentrated gas.

[0111] (Gas separation membrane) The gas separation membrane (51) is as described above. The gas separation membrane (51) is superimposed on the supply-side flow channel material (101) and the permeate-side flow channel material (102) and is wound spirally around the central tube (100).

[0112] A single spiral module can be equipped with multiple gas separation membranes (51). By equipping these wound components, the spiral gas separation membrane module (50) has a generally cylindrical appearance with the longitudinal direction of the central tube (100) as its major axis.

[0113] The gas separation membranes (51) are stacked so that the sheet layer side (supply side) faces each other, and the porous support layer or substrate side (permeation side) faces each other.

[0114] A supply-side flow channel material (101) is inserted between the separation-function layer sides of the gas separation membrane (51), and a permeate-side flow channel material (102) is inserted between the permeate-side sides.

[0115] The supply-side flow path is open at both ends in the longitudinal direction of the central tube (100). In other words, a supply-side inlet is provided at one end of the spiral-type gas separation membrane module (50), and a supply-side outlet is provided at the other end. On the other hand, the supply-side flow path is sealed at the end on the inside in the winding direction, that is, the end on the central tube side. The sealing is formed by folding the gas separation membrane, bonding the gas separation membrane with hot melt or chemical adhesive, or fusing the gas separation membranes together with a laser or the like.

[0116] (channel material) The supply-side channel material (101) and the permeate-side channel material (102) are spacers that ensure a flow path between the gas separation membranes. The permeate-side channel material and the supply-side channel material may be the same material or different materials. Hereinafter, the permeate-side channel material and the supply-side channel material will be collectively referred to as "channel material".

[0117] Examples of flow channel materials include porous sheets such as nets, nonwoven fabrics, woven fabrics, knitted fabrics, and films. Protrusions made of resin or the like may be provided on one or both sides of the sheet. Alternatively, the protrusions may be directly fixed to the gas separation membrane and used as the flow channel material.

[0118] If the flow channel material has a sheet and protrusions, the shape of the protrusions may be dots, curves, or straight lines. If they are curved or straight, the gas flow can be controlled along their shape. The composition of the protrusions should not deteriorate depending on the pressure, temperature, or type of gas supplied during use.

[0119] The flow channel material is preferably made of a thermoplastic resin. From the viewpoint of suppressing damage to the gas separation membrane, the thermoplastic resin is preferably polyester, nylon, polyphenylene sulfide, polyethylene, polypropylene, polysulfone, polyethersulfone, ABS (acrylonitrile-butadiene-styrene) resin, or UV-curable resin.

[0120] The thickness of at least one, preferably both, of the supply-side channel material and the permeate-side channel material is preferably 1000 μm or less, more preferably 700 μm or less, and particularly preferably 400 μm or less. By making the channel material thin in this way, the rigidity against bending is reduced, making it less prone to cracking. In addition, by making the channel material thin, the area of ​​the gas separation membrane that can be filled can be increased while maintaining the volume of the gas separation membrane module.

[0121] 4. Gas Separation System The aforementioned gas separation membrane can selectively permeate small molecular gases such as hydrogen, helium, water vapor, and ammonia, and is applicable to gas separation systems.

[0122] The gas separation system according to this embodiment includes the following steps. (1) A step of supplying a supply gas containing gas A, which is a permeable component, and gas B, which is an impermeable component, to one side of a gas separation membrane. (2) A step of obtaining a gas from the other side of the gas separation membrane in which the molar ratio of gas A / gas B is greater than that of the supplied gas.

[0123] In other words, this separation system utilizes the fact that the permeability of the gas separation membrane to gas A is different from that to the unwanted component gas B, thereby obtaining a permeate gas with a reduced concentration of gas B from a supply gas of gas A and gas B.

[0124] While gas B is not limited to a specific type, it is preferable that the supply gas contains at least one of the following gases as gas B: for example, oxygen, nitrogen, and methane. This is because the gas separation membrane can efficiently separate gases with small molecular diameters, such as hydrogen, helium, water vapor, and ammonia, due to the large difference in permeability between these gases and oxygen, nitrogen, and methane.

[0125] In the gas separation system of the present invention, the spiral-type gas separation membrane module described above can be used. Furthermore, in the gas separation system of the present invention, the pressure vessel can be connected in series and / or parallel and used while housed in the pressure vessel.

[0126] In step (1), the supply gas may be pressurized by a compressor and supplied to the gas separation membrane (its elements), or the permeate side of the gas separation membrane may be depressurized by a pump.

[0127] Furthermore, multiple elements may be connected in series. When multiple elements are used, the downstream elements may be supplied with either the permeate gas or the impermeate gas from the upstream elements. Alternatively, the permeate gas or impermeate gas from the downstream elements may be mixed with the supply gas from the upstream elements. The permeate gas or impermeate gas may be supplied to the downstream elements, which may then be pressurized with a compressor.

[0128] The gas supply pressure is not particularly limited, but 0.1 MPa to 10 MPa is preferred. Setting it to 0.1 MPa or higher increases the gas permeation rate, while setting it to 10 MPa or lower prevents pressure deformation of the gas separation membrane and its elemental components. The value of "supply side pressure / permeation side pressure" is also not particularly limited, but 1.01 to 100,000 is preferred, 1.10 to 1,000 is more preferred, and 1.50 to 100 is particularly preferred. Setting the value of "supply side pressure / permeation side pressure" to 1.01 or higher increases the gas permeation rate, while setting it to 100,000 or lower suppresses the power costs for increasing the supply side pressure and decreasing the permeation side pressure.

[0129] The gas supply temperature is not particularly limited, but is preferably between 0°C and 200°C, and more preferably between 15°C and 180°C. Setting the temperature to 15°C or higher provides good gas permeability, while setting it to 180°C or lower prevents thermal deformation of the components constituting the gas separation membrane element. Using the above gas separation membrane, it is possible to supply gas at temperatures of 80°C or higher, 90°C or higher, or 100°C or higher.

[0130] 5.Applications The technology of the present invention can be used in at least one step selected from the following: separation of gases in the manufacturing process of optical fibers, semiconductors, and electrical products; separation of gases produced in reactions such as natural gas, city gas, biogas, and methanation, separation of gases containing unreacted raw materials and by-products; separation of gases generated from water electrolysis equipment, etc.; and separation of gases to concentrate a target gas from a supply gas.

[0131] The technology of the present invention may be used for pre-use inspection of the gas separation membrane used in the aforementioned manufacturing process. Alternatively, the use of the separation membrane module in the manufacturing process may be temporarily interrupted and used for inspection.

[0132] The technology of the present invention enables the efficient production of optical fibers, semiconductors, and electrical products by verifying the performance of gas separation membranes through inspection. Various gases can be separated and produced in at least one step selected from gases containing unreacted raw materials and by-products after reactions such as natural gas, city gas, biogas, and methanation, gases from fermentation and enzymatic reaction processes, and gases generated from water electrolysis equipment. [Examples]

[0133] The present invention will be described in more detail below with reference to examples, but the present invention is not limited in any way by these examples.

[0134] A. Fabrication of porous support membrane Unless otherwise specified, the temperature condition is room temperature (25°C).

[0135] Polyester nonwoven fabric made of long fibers as the base material (air permeability 2.0 cc / cm²) 2 A porous support layer was formed by casting a 16 wt% dimethylformamide (DMF) solution of polysulfone (PSf) to a thickness of 200 μm under conditions of 25°C onto the substrate ( / sec), and immediately immersing it in pure water for 5 minutes. In this way, a porous support film having a substrate and a porous support layer was fabricated.

[0136] B. Fabrication of the separation function layer (Gas separation membrane P) The porous support membrane obtained in A. was immersed in a 0.2 wt% piperazine aqueous solution for 2 minutes. The porous support membrane was slowly lifted vertically, and nitrogen was blown from an air nozzle to remove excess aqueous solution from the surface of the porous support layer.

[0137] Next, an n-decane solution containing 0.2% by weight of trimesinate chloride (TMC) was applied to the porous support layer so that the surface was completely wetted, and the mixture was left to stand at 25°C for 100 seconds. After that, to remove excess solution from the separation membrane, the membrane was held vertically to allow the solution to flow, and then deliquorized by blowing 25°C air onto it using a feeder.

[0138] (Gas separation membrane Q) The porous support film obtained in A was immersed for 2 minutes in an aqueous solution containing 2.0 wt% m-phenylenediamine (m-PDA) and 1.0 wt% ε-caprolactam. The porous support film was slowly lifted vertically, and nitrogen was blown from an air nozzle to remove excess aqueous solution from the surface of the porous support layer.

[0139] Next, an n-decane solution containing 0.10% by weight of trimesinate chloride (TMC) was applied to the porous support layer until the surface was completely wetted, and dried at 25°C for 180 seconds. Then, to remove excess solution from the separation membrane, the membrane was held vertically to allow the solution to flow, and the membrane was further dehydrated by blowing 25°C air onto it using a feeder.

[0140] (Gas separation membrane R) The porous support film obtained in A. was immersed in a 2.0 wt% m-phenylenediamine (m-PDA) aqueous solution for 2 minutes. The porous support film was slowly lifted vertically, and nitrogen was blown from an air nozzle to remove excess aqueous solution from the surface of the porous support layer.

[0141] Next, an n-decane solution containing 0.10% by weight of trimesinate chloride (TMC) was applied to the porous support layer until the surface was completely wetted, and dried at 50°C for 60 seconds. Then, to remove excess solution from the separation membrane, the membrane was held vertically to allow the solution to flow, and the membrane was further deliquidated by blowing 25°C air onto it using a feeder.

[0142] (Gas separation membrane S) The porous support film obtained in A. was immersed in a 4.0 wt% m-phenylenediamine (m-PDA) aqueous solution for 2 minutes. The porous support film was slowly lifted vertically, and nitrogen was blown from an air nozzle to remove excess aqueous solution from the surface of the porous support layer.

[0143] Next, an n-decane solution containing 0.20 wt% trimesinate chloride (TMC) was applied to the porous support layer until the surface was completely wetted, and dried at 80°C for 60 seconds. Then, to remove excess solution from the separation membrane, the membrane was held vertically to allow the solution to flow, and the membrane was further deliquidated by blowing 25°C air onto it using a feeder.

[0144] C. Sheet layer a A 16% by weight solution of TSE389 (manufactured by Momentive Performance Materials) was prepared by dissolving TSE389 in hexane (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.). This solution was applied to a PP plate and uniformly coated at a rate of 10 m / min using a bar coater, and allowed to stand for 24 hours to obtain a sheet layer.

[0145] D. Sheet layer b An aluminum vapor-deposited barrier film (VM-PET, 1310, manufactured by Toray Film Processing Co., Ltd.) was cut to a width of 300 mm to obtain sheet layer b.

[0146] From the gas permeability measurement described later, the water vapor permeability is 0.5 nmol / m³. 2 It was / s / Pa.

[0147] E. Sheet layer c An activated carbon sheet (manufactured by UES Co., Ltd., product number KF, thickness 0.1 mm) was cut to a width of 300 mm to obtain sheet layer c. The activated carbon contained in sheet layer c can adsorb moisture, organic matter, and other substances.

[0148] F. Sheet layer d A sheet made of polyvinylidene chloride (Saran Wrap®, manufactured by Asahi Kasei Home Products Corporation) was cut to a width of 300 mm to obtain sheet layer d.

[0149] From the gas permeability measurement described later, the water vapor permeability is 4.7 nmol / m³. 2 It was / s / Pa.

[0150] G. Sheet layer e A polyolefin sheet (Diawrap® PO-S, manufactured by Mitsubishi Chemical Corporation) was cut to a width of 300 mm to obtain sheet layer e.

[0151] From the gas permeability measurement described later, the water vapor permeability is 154 nmol / m³. 2 It was / s / Pa.

[0152] H. Gas Permeability Measurement (Helium, Hydrogen, Nitrogen, Methane, Water Vapor Permeability and Selectivity) A separation membrane was placed between the supply cell and the permeate cell in a test cell having a supply cell and a permeate cell. Helium and nitrogen were used as the measured gases, and the pressure change on the permeate side per unit time for helium, hydrogen, nitrogen, and methane was measured at a measurement temperature of 25°C in accordance with the pressure sensor method of ISO 15105-1 (2007). Here, the supply side was set to 100 kPa and the permeate side to 0 kPa, and the pressure difference between the supply side and the permeate side was set to 100 kPa. Next, the permeation rate Q of the permeated gas was calculated using the following formula, and the gas permeability was determined by the arithmetic mean of measurements taken at five arbitrary points on the same membrane. Subsequently, selectivity was calculated as the ratio of the permeation rates of each component gas. Note that STP means standard conditions. Q = [Gas permeation rate (m³) 3 ·STP)] / [Membrane area (m 2() × Time (s) × Pressure difference (Pa) F. Measurement of adhesive strength Adhesion strength was measured using a Tensilon testing machine (RTG-1210, manufactured by A&D Co., Ltd.). The sheet layer and separation function layer of a gas separation membrane with a coating layer (hereinafter referred to as "Type T test specimen") were each secured with grips on the tensile testing machine, and a peel test was performed at a peeling speed of 200 mm per minute until a peeling distance of at least 200 mm was reached, and the peel strength was measured. The peel strength was defined as the average value of the peel strength at peeling distances of 50 to 150 mm, and the average value obtained by repeating this operation 10 times was defined as the peel strength. However, if the support layer of the gas separation membrane ruptured due to the stress of the peel test while maintaining adhesion between the sheet layers up to a peeling distance of 150 mm, and delamination occurred between the substrate and the sheet layer, the maximum stress at the time of delamination was defined as the peel strength.

[0153] G. Sheet layer thickness The sheet layer thickness was measured using a PEACOCK digital thickness gauge manufactured by Ozaki Seisakusho Co., Ltd. Twenty measurements were taken in the width direction, and the average value was calculated.

[0154] (Example 1) The gas separation membrane P obtained in B has a membrane area of ​​25 cm². 2 It was cut into a circular shape. The sheet a layer with a thickness of 51 μm obtained in C. was cut to 25 cm 2 After cutting out a circular shape, it was attached to the separation function layer side of the gas separation membrane P, taking care to prevent the formation of air bubbles or wrinkles. The resulting gas separation membrane was then compressed in a hydraulic press at a pressure of 1.0 MPa and evaluated. The results are shown in Table 1.

[0155] (Example 2) The gas separation membrane Q obtained in B has a membrane area of ​​25 cm². 2 It was cut into a circular shape. The sheet a layer with a thickness of 51 μm obtained in C. was cut to 25 cm 2 After cutting out a circular shape, it was attached to the separation function layer side of the gas separation membrane Q, taking care to prevent the formation of air bubbles or wrinkles. The resulting gas separation membrane was then compressed in a hydraulic press at a pressure of 1.0 MPa and evaluated. The results are shown in Table 1.

[0156] (Example 3) The gas separation membrane R obtained in B has a membrane area of ​​25 cm². 2 It was cut into a circular shape. The sheet a layer with a thickness of 51 μm obtained in C. was cut to 25 cm 2 After cutting out a circular shape, it was attached to the separation function layer side of the gas separation membrane R, taking care to prevent the formation of air bubbles or wrinkles. The resulting gas separation membrane was then compressed in a hydraulic press at a pressure of 1.0 MPa and evaluated. The results are shown in Table 1.

[0157] (Example 4) The gas separation membrane S obtained in B has a membrane area of ​​25 cm². 2 It was cut into a circular shape. The sheet a layer with a thickness of 51 μm obtained in C. was cut to 25 cm 2 After cutting out a circular shape, it was attached to the separation function layer side of the gas separation membrane S, taking care to prevent the formation of air bubbles or wrinkles. The resulting gas separation membrane was then compressed in a hydraulic press at a pressure of 1.0 MPa and evaluated. The results are shown in Table 1.

[0158] (Example 5) The gas separation membrane S obtained in B has a membrane area of ​​25 cm². 2 It was cut into a circular shape. The sheet a layer with a thickness of 51 μm obtained in C. was cut to 25 cm 2 After cutting out a circular shape, it was attached to the separation function layer side of the gas separation membrane S, taking care to prevent the formation of air bubbles or wrinkles. The resulting gas separation membrane was then compressed in a hydraulic press at a pressure of 0.1 MPa and evaluated. The results are shown in Table 2.

[0159] (Example 6) The gas separation membrane S obtained in B has a membrane area of ​​25 cm². 2 It was cut into a circular shape. The sheet a layer with a thickness of 51 μm obtained in C. was cut to 25 cm 2 After cutting out a circular shape, it was attached to the separation function layer side of the gas separation membrane S, taking care to prevent the formation of air bubbles or wrinkles. The resulting gas separation membrane was then compressed in a hydraulic press at a pressure of 0.5 MPa and evaluated. The results are shown in Table 2.

[0160] (Example 7) The gas separation membrane S obtained in B has a membrane area of ​​25 cm². 2 It was cut into a circular shape. The sheet a layer with a thickness of 51 μm obtained in C. was cut to 25 cm 2 After cutting out a circular shape, it was attached to the separation function layer side of the gas separation membrane S, taking care to prevent the formation of air bubbles or wrinkles. The resulting gas separation membrane was then compressed in a hydraulic press at a pressure of 10 MPa and evaluated. The results are shown in Table 2.

[0161] (Example 8) The gas separation membrane S obtained in B has a membrane area of ​​25 cm². 2 It was cut into a circular shape. The sheet a layer with a thickness of 13 μm obtained in C. was cut to 25 cm 2 After cutting out a circular shape, it was attached to the separation function layer side of the gas separation membrane S, taking care to prevent the formation of air bubbles or wrinkles. The resulting gas separation membrane was then compressed in a hydraulic press at a pressure of 1.0 MPa and evaluated. The results are shown in Table 2.

[0162] (Example 9) The gas separation membrane S obtained in B has a membrane area of ​​25 cm². 2 It was cut into a circular shape. The sheet a layer with a thickness of 95 μm obtained in C. was cut to 25 cm 2 After cutting out a circular shape, it was attached to the separation function layer side of the gas separation membrane S, taking care to prevent the formation of air bubbles or wrinkles. The resulting gas separation membrane was then compressed in a hydraulic press at a pressure of 1.0 MPa and evaluated. The results are shown in Table 2.

[0163] (Example 10) The gas separation membrane S obtained in B has a membrane area of ​​25 cm². 2 It was cut into a circular shape. The sheet a layer obtained in C, with a thickness of 482 μm, was cut to 25 cm. 2 After cutting out a circular shape, it was attached to the separation function layer side of the gas separation membrane S, taking care to prevent the formation of air bubbles or wrinkles. The resulting gas separation membrane was then compressed in a hydraulic press at a pressure of 1.0 MPa and evaluated. The results are shown in Table 2.

[0164] (Example 11) The gas separation membrane S obtained in B has a membrane area of ​​25 cm².2 It was cut into a circular shape. The sheet a layer with a thickness of 51 μm obtained in C. was cut to 25 cm 2 After cutting out a circular shape, it was attached to the separation function layer side of the gas separation membrane S, taking care to prevent the formation of air bubbles or wrinkles. The resulting gas separation membrane was then pressurized to a pressure of 1.0 MPa using compressed air in a pressure-resistant vessel and evaluated. The results are shown in Table 2.

[0165] [Table 1]

[0166] [Table 2]

[0167] (Comparative Example 1) The gas separation membrane P obtained in B has a membrane area of ​​25 cm². 2 When the material was cut into a circular shape and evaluated as a gas separation membrane without forming a sheet layer, the results were as shown in Table 3. Because there was no sheet layer, permeation from the coarse pores was not suppressed, and the selectivity could not be sufficiently improved.

[0168] (Comparative Example 2) The gas separation membrane Q obtained in B has a membrane area of ​​25 cm². 2 When the material was cut into a circular shape and evaluated as a gas separation membrane without forming a sheet layer, the results were as shown in Table 3. Because there was no sheet layer, permeation from the coarse pores was not suppressed, and the selectivity could not be sufficiently improved.

[0169] (Comparative Example 3) The gas separation membrane R obtained in B has a membrane area of ​​25 cm². 2 When the material was cut into a circular shape and evaluated as a gas separation membrane without forming a sheet layer, the results were as shown in Table 3. Because there was no sheet layer, permeation from the coarse pores was not suppressed, and the selectivity could not be sufficiently improved.

[0170] (Comparative Example 4) The gas separation membrane S obtained in B has a membrane area of ​​25 cm². 2 When the material was cut into a circular shape and evaluated as a gas separation membrane without forming a sheet layer, the results were as shown in Table 3. Because there was no sheet layer, permeation from the coarse pores was not suppressed, and the selectivity could not be sufficiently improved.

[0171] (Comparative Example 5) The gas separation membrane S obtained in B has a membrane area of ​​25 cm². 2 The material was cut into a circular shape. The resulting gas separation membrane was evaluated by pressurizing it at a pressure of 1.0 MPa in a hydraulic press, and the results are shown in Table 3. Although the permeation of coarse pores was slightly suppressed by compaction, the selectivity could not be sufficiently improved.

[0172] [Table 3]

[0173] (Example 12) After cutting the gas separation membrane Q obtained in B. to a width of 300 mm, the 300 mm wide sheet layer b obtained in D. was attached to the separation function layer side of the gas separation membrane Q, taking care not to generate bubbles or wrinkles. Afterward, the membrane was air-dried in a 25°C greenhouse, folded in half, and the supply-side channel material (Diomesh PET-Screen 100-55PT (manufactured by innovex)) was sandwiched between the folded separation membranes. The permeate-side channel material (Diomesh PET-Screen 100-55PT (manufactured by innovex)) was placed on the permeate side of the gas separation membrane, and adhesive was applied to the three ends of the permeate-side channel material. These laminates (effective membrane area 1.0 m²) 2 A separation membrane module Qb with a diameter of 2.5 inches was fabricated by spirally winding the material around an ABS resin water collection pipe (length: 300 mm, diameter: 17 mm, with 80 holes arranged in a straight line on the wall surface in 2 rows). Here, the separation membrane module Qb was loaded into a pressure vessel (ROPV, R25C1000E, 2514). The supply gas vent side of the central tube 100 was sealed. Subsequently, 0.5 MPa of air was vented through the supply side of the separation membrane module Qb for 2 hours.

[0174] Subsequently, a supply gas (2 L / min) containing 50 mol% helium and 50 mol% air at 70% humidity was supplied to the separation membrane module Qb. The supply pressure was adjusted to 0.02 MPa.

[0175] The permeate side of the separation membrane module Qb was depressurized by connecting a vacuum pump (diaphragm type, KNF N810.3FT.18(EX)). The pressure was measured to be 10 kPa. The gas composition and flow rate of the impermeable and permeable gases discharged from a pressure vessel loaded with separation membrane module Q were measured. The measurement results are shown in Table 4.

[0176] (Example 13) After cutting the gas separation membrane Q obtained in B. to a width of 300 mm, it was air-dried in a greenhouse at 25°C. Then, TSE389 (manufactured by Momentive Performance Materials) was dissolved in hexane (Fujifilm Wako Pure Chemical Industries, Ltd.) to prepare a 1 wt% solution. This solution was applied at a rate of 400 mL / m² to the separation functional layer surface of the gas separation membrane A prepared as described above. 2 A coating layer was formed by applying a 10 mil bar coater to the surface. Finally, the gas separation membrane D was obtained by vacuum drying at 40°C for more than 12 hours. Observation using a scanning electron microscope, as described above, showed that the thickness of the coating layer was 0.3 μm. The 300 mm wide sheet layer b obtained in D was attached to the coating layer side of the gas separation membrane Q, taking care to avoid generating air bubbles or wrinkles. The separation membrane module Qb2 was fabricated in the same manner as in Example 12. The measurement results are shown in Table 4. Moisture was removed by the sheet layer, improving helium purity.

[0177] (Example 14) After cutting the gas separation membrane Q obtained in B. to a width of 300 mm, it was air-dried in a greenhouse at 25°C. Then, TSE389 (manufactured by Momentive Performance Materials) was dissolved in hexane (Fujifilm Wako Pure Chemical Industries, Ltd.) to prepare a 1 wt% solution. This solution was applied at a rate of 400 mL / m² to the separation functional layer surface of the gas separation membrane A prepared as described above. 2 A coating layer was formed by applying a 10 mil bar coater to the surface. Finally, the gas separation membrane D was obtained by vacuum drying at 40°C for more than 12 hours. Observation using a scanning electron microscope, as described above, showed that the thickness of the coating layer was 0.3 μm. The 300 mm wide sheet layer b obtained in D was attached to the coating layer side of the gas separation membrane Q, taking care to prevent the formation of air bubbles or wrinkles.

[0178] Furthermore, the 300 mm wide sheet layer c obtained in E. was attached to the opposite side of the separation functional layer of the gas separation membrane Q to prevent the formation of air bubbles or wrinkles. The separation membrane module Qb2 was fabricated using the same procedure as in Example 12. The measurement results are shown in Table 4. Trace amounts of moisture were removed even in the sheet layer, improving helium purity.

[0179] (Example 15) After cutting the gas separation membrane Q obtained in B. to a width of 300 mm, it was air-dried in a greenhouse at 25°C. Then, TSE389 (manufactured by Momentive Performance Materials) was dissolved in hexane (Fujifilm Wako Pure Chemical Industries, Ltd.) to prepare a 1 wt% solution. This solution was applied at a rate of 400 mL / m² to the separation functional layer surface of the gas separation membrane A prepared as described above. 2 A coating layer was formed by applying a 10 mil bar coater to the surface. Finally, the gas separation membrane D was obtained by vacuum drying at 40°C for more than 12 hours. Observation using a scanning electron microscope, as described above, showed that the thickness of the coating layer was 0.3 μm. The 300 mm wide sheet layer d obtained in F was attached to the coating layer side of the gas separation membrane Q, ensuring that no bubbles or wrinkles were generated. The separation membrane module Qb4 was fabricated in the same manner as in Example 12. The measurement results are shown in Table 4. Moisture was removed by the sheet layer, improving helium purity.

[0180] (Example 16) After cutting the gas separation membrane Q obtained in B. to a width of 300 mm, it was air-dried in a greenhouse at 25°C. Then, TSE389 (manufactured by Momentive Performance Materials) was dissolved in hexane (Fujifilm Wako Pure Chemical Industries, Ltd.) to prepare a 1 wt% solution. This solution was applied at a rate of 400 mL / m² to the separation functional layer surface of the gas separation membrane A prepared as described above. 2 A coating layer was formed by applying a 10 mil bar coater to the surface. Finally, the gas separation membrane D was obtained by vacuum drying at 40°C for more than 12 hours. Observation using a scanning electron microscope, as described above, showed that the thickness of the coating layer was 0.3 μm. The 300 mm wide sheet layer e obtained in G was attached to the coating layer side of the gas separation membrane Q, taking care to avoid the generation of bubbles or wrinkles. The separation membrane module Qb5 was fabricated in the same manner as in Example 12. The measurement results are shown in Table 4. Moisture was removed by the sheet layer, improving helium purity.

[0181] (Comparative Example 6) After cutting the gas separation membrane Q obtained in B. to a width of 300 mm, a separation membrane module Q was fabricated in the same manner as in Example 12, without forming a sheet layer. The measurement results are shown in Table 4. The permeate flow rate was lower than in Example 12. Also, water vapor permeated the separation membrane and water droplets came out of the vacuum pump outlet, so the test was stopped to protect the pump.

[0182] [Table 4] [Industrial applicability]

[0183] The gas separation membrane of the present invention is suitably used for separating and purifying a specific gas from a gas mixture. [Explanation of Symbols]

[0184] 50: Spiral-type gas separation membrane module 51: Gas separation membrane 52: Porous support layer 53: Separation functional layer 54: Sheet layer 55: Base material 56: Covering layer 100: Central tube 101: Supply side channel material 102: Permeate side channel material G1: Supply gas G2: Permeable gas G3: Concentrated gas

Claims

1. A gas separation membrane having at least a separation functional layer and a sheet layer.

2. The gas separation membrane according to claim 1, having a coating layer on the separation functional layer.

3. A gas separation membrane according to claim 1, having a plurality of sheet layers.

4. The water vapor permeability of the sheet layer is 0.001 to 100 nmol / m³. ２ A gas separation membrane according to claim 1, wherein the pressure is / s / Pa.

5. The gas separation membrane according to claim 1, wherein the main component of the separation functional layer is a crosslinked aromatic polyamide.

6. The gas separation membrane according to claim 1, wherein the thickness of the sheet layer is 20 μm or more and 3000 μm or less.

7. The gas separation membrane according to claim 1, wherein the sheet layer comprises at least one substance selected from the group consisting of polyolefin, fluororesin, polystyrene, silicone, microporous polymer (PIM), phenolic resin, urethane resin, aluminum, silica, chromium, copper, gold, titanium, and palladium.

8. A method for producing a gas separation membrane, comprising the step of pressurizing the gas separation membrane described in claim 1 at 0.1 MPa or more and 10 MPa or less.

9. The gas separation membrane according to claim 1, characterized in that it is used in at least one step selected from the following: separation of gases in the manufacturing process of optical fibers, semiconductors, and electrical products; separation of gases produced in the reaction of natural gas, city gas, biogas, and methanation; separation of gases containing unreacted raw materials and by-products; separation of gases generated from water electrolysis equipment; and separation of gases to concentrate a target gas from a mixed gas.

10. A method for manufacturing optical fibers, characterized by using the gas separation membrane described in claim 1.

11. A method for manufacturing a semiconductor, characterized by using the gas separation membrane described in claim 1.

12. A method for manufacturing an electrical product, characterized by using the gas separation membrane described in claim 1.

13. A method for producing a gas, characterized by using the gas separation membrane described in claim 1, for separating at least one gas selected from natural gas, city gas, biogas, gases produced in methanation reactions, gases containing unreacted raw materials and by-products, gases from fermentation and enzymatic reaction processes, and gases generated from water electrolysis equipment.

14. An optical fiber characterized by being manufactured using the gas separation membrane described in claim 1.

15. A semiconductor characterized by being manufactured using the gas separation membrane described in claim 1.

16. An electrical product characterized by being manufactured using the gas separation membrane described in claim 1.

17. A gas separation apparatus characterized by using the gas separation membrane described in claim 1, for separating at least one gas selected from natural gas, city gas, biogas, gases produced in methanation reactions, gases containing unreacted raw materials and by-products, gases from fermentation and enzymatic reaction processes, and gases generated from water electrolysis equipment.

18. A spiral-type gas separation membrane module comprising the gas separation membrane described in claim 1, a supply-side flow channel material, and a permeate-side flow channel material, all surrounded by a central tube.

19. A gas separation system comprising a spiral-type gas separation membrane module as described in claim 18.

20. He or H using the gas separation system according to claim 19 ２ A method for purifying it.

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