Separation membrane components

Abstract

The separation membrane assembly (21) comprises: a separation membrane complex (1) having a support (11) and a separation membrane (12) disposed on the support (11); a storage container (22) for storing the separation membrane complex (1); and a sealing member (23) in close contact with a support surface (24) disposed inside the storage container (22) and a supported surface (14) of the separation membrane complex (1). A first static friction coefficient between the sealing member (23) and the supported surface (14) and / or a second static friction coefficient between the sealing member (23) and the supporting surface (24) is 0.5 or less. A value obtained by multiplying the first static friction coefficient and / or the second static friction coefficient by the compressive force [N] of the sealing member (23) and then dividing by the mass [kg] of the separation membrane complex (1) is greater than 0.7.

Description

Technical Field

[0001] The present invention relates to a separation membrane module.

[0002] [References to related applications]

[0003] This application claims the benefit of priority from Japanese patent application JP2020-098750, filed on June 5, 2020, the disclosure of which is incorporated herein in its entirety. Background Art

[0004] In the past, separation membrane components have been used. For example, Japanese Patent Publication No. 2020-23432 (Document 1) discloses a separation membrane component, which is obtained by joining a composite of zeolite and an inorganic porous support and a dense component with an inorganic adhesive. In addition, Japanese Patent Publication No. 2009-226395 (Document 2) discloses a separation membrane component, which is obtained by connecting a plurality of separation membrane components in series and loading them into a pressure-resistant container. In the separation membrane component, a friction resistance reducing structure that reduces the friction resistance against the inner surface of the pressure-resistant container is provided in the connecting component that connects the separation membrane components. It should be noted that a method for manufacturing DDR type zeolite is described in Japanese Patent Publication No. 2004-83375 (Document 3) and International Publication No. WO2011 / 105511 (Document 4). In addition, International Publication No. WO2018 / 180095 (Document 5) describes a method for checking gas leakage for a separation membrane component.

[0005] However, in the separation membrane assembly, a separation membrane complex having a separation membrane and a support body is supported in a storage container. In one example of a separation membrane assembly, a sealing component that fits closely to the inner surface of the container body of the storage container and the outer surface of the separation membrane complex is provided between the two, and the separation membrane complex is supported in the storage container using the sealing component. Usually, the friction between the sealing component and the outer surface of the separation membrane complex and the inner surface of the container body is large (sliding is poor), and the replacement of the sealing component is very troublesome. However, compared with the separation membrane, the sealing component deteriorates earlier due to the use conditions (temperature, gas type, etc.), and therefore, the sealing component needs to be replaced regularly. In order to improve maintainability, it is also necessary to make the sealing component easy to replace.

[0006] For example, as described in Japanese Patent Application Laid-Open No. 2009-226395 (reference 2), it has been considered to reduce the frictional force (facilitate sliding) by providing a sealing member with two or more protrusions. However, when vibration or shock acts on the separation membrane module, sliding occurs between the sealing member and the outer surface of the separation membrane complex or the inner surface of the container body, making it impossible to properly support the separation membrane complex within the storage container and ensure airtightness. This problem also occurs when the separation membrane complex is mounted on a supporting surface other than the inner surface of the container body within the storage container through the sealing member. Summary of the Invention

[0007] The present invention relates to a separation membrane module, and an object thereof is to appropriately support a separation membrane complex in a storage container and to facilitate attachment and detachment of the separation membrane complex to and from the storage container.

[0008] The separation membrane assembly involved in the present invention comprises: a separation membrane complex, which has a support body and a separation membrane arranged on the support body; a storage container, which stores the separation membrane complex; and a sealing component, which is in close contact with the supporting surface and the supported surface of the separation membrane complex provided inside the storage container, wherein the first static friction coefficient between the sealing component and the supported surface and / or the second static friction coefficient between the sealing component and the supporting surface are less than 0.5, and the value obtained by multiplying the first static friction coefficient and / or the second static friction coefficient by the compression force [N] of the sealing component and dividing it by the mass [kg] of the separation membrane complex is greater than 0.7.

[0009] According to the present invention, the separation membrane complex can be appropriately supported in the storage container, and the separation membrane complex can be easily attached to and detached from the storage container.

[0010] Preferably, when the separation membrane module is heated at 100° C. for 72 hours, the ratio of the gas permeation rate of the separation membrane complex after heating to the gas permeation rate of the separation membrane complex before heating is 80% or more.

[0011] Preferably, a lubricant is applied to the surface of the sealing member.

[0012] Preferably, the mass reduction rate of the lubricant when the lubricant is heated at 100° C. for 72 hours is 5% or less.

[0013] Preferably, the supporting surface is a portion of the inner surface of the main body of the storage container, and the supported surface is a portion of the outer surface of the separation membrane complex.

[0014] Preferably, the separation membrane is a zeolite membrane.

[0015] Preferably, the zeolite membrane has a pore structure with 8-membered oxygen rings or less.

[0016] The above-mentioned object and other objects, features, aspects and advantages will become more apparent from the following detailed description of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a diagram showing the structure of a separation device.

[0018] Figure 2 is a cross-sectional view of a zeolite membrane composite.

[0019] Figure 3 This is a cross-sectional view showing an enlarged portion of the zeolite membrane composite.

[0020] Figure 4 This is a diagram showing how the static friction coefficient between the sealing member and the supporting surface of the storage container is measured.

[0021] Figure 5 This is a diagram showing how the static friction coefficient between the sealing member and the supported surface of the zeolite membrane composite is measured.

[0022] Figure 6 This is a diagram showing another example of a separation membrane module. DETAILED DESCRIPTION

[0023] Figure 1 It is a diagram showing a schematic configuration of a separation device 2 according to one embodiment of the present invention. Figure 1 Parallel oblique lines are omitted in the cross-section of a portion of the structure. Separation device 2 is a device that separates substances with high permeability to the zeolite membrane composite 1, described later, from a fluid (i.e., gas or liquid). The purpose of separation in separation device 2 can be, for example, to extract highly permeable substances from the fluid or to concentrate less permeable substances.

[0024] The fluid may be a gas or a mixed gas containing multiple gases, a liquid or a mixed liquid containing multiple liquids, or a gas-liquid two-phase fluid containing both gas and liquid.

[0025] The fluid includes one or more substances such as hydrogen (H2), helium (He), nitrogen (N2), oxygen (O2), water (H2O), water vapor (H2O), carbon monoxide (CO), carbon dioxide (CO2), nitrogen oxides, ammonia (NH3), sulfur oxides, hydrogen sulfide (H2S), sulfur fluoride, mercury (Hg), arsine (AsH3), hydrogen cyanide (HCN), carbonyl sulfide (COS), C1-C8 hydrocarbons, organic acids, alcohols, thiols, esters, ethers, ketones and aldehydes.

[0026] Nitrogen oxides are compounds of nitrogen and oxygen. These nitrogen oxides are nitric oxide (NO), nitrogen dioxide (NO2), nitrous oxide (also known as dinitrogen monoxide) (N2O), dinitrogen trioxide (N2O3), dinitrogen tetroxide (N2O4), dinitrogen pentoxide (N2O5), etc. X (Nox) gas.

[0027] Sulfur oxides are compounds of sulfur and oxygen. The above-mentioned sulfur oxides are such as sulfur dioxide (SO2), sulfur trioxide (SO3), etc., which are called SO X (Sox) gas.

[0028] Sulfur fluoride is a compound of fluorine and sulfur. The above-mentioned sulfur fluoride is, for example, disulfur difluoride (FSSF, S=SF2), sulfur difluoride (SF2), sulfur tetrafluoride (SF4), sulfur hexafluoride (SF6) or disulfur decafluoride (SF6). 10 )wait.

[0029] C1 to C8 hydrocarbons are hydrocarbons having 1 or more and 8 or less carbon atoms. C3 to C8 hydrocarbons may be any of linear compounds, side chain compounds, and cyclic compounds. In addition, C2 to C8 hydrocarbons may be any of saturated hydrocarbons (i.e., hydrocarbons having no double bonds or triple bonds in the molecule) and unsaturated hydrocarbons (i.e., hydrocarbons having double bonds and / or triple bonds in the molecule). C1 to C4 hydrocarbons include, for example, methane (CH4), ethane (C2H6), ethylene (C2H4), propane (C3H8), propylene (C3H6), n-butane (CH3(CH2)2CH3), isobutane (CH(CH3)3), 1-butene (CH2=CHCH2CH3), 2-butene (CH3CH=CHCH3), or isobutene (CH2=C(CH3)2).

[0030] The organic acid mentioned above is a carboxylic acid or a sulfonic acid. Carboxylic acids include formic acid (CH2O2), acetic acid (C2H4O2), oxalic acid (C2H2O4), acrylic acid (C3H4O2), or benzoic acid (C6H5COOH). Sulfonic acids include ethanesulfonic acid (C2H6O3S). The organic acid may be a chain compound or a cyclic compound.

[0031] The above-mentioned alcohol is, for example, methanol (CH3OH), ethanol (C2H5OH), isopropyl alcohol (2-propanol) (CH3CH(OH)CH3), ethylene glycol (CH2(OH)CH2(OH)) or butanol (C4H9OH).

[0032] Thiols are organic compounds with hydrogenated sulfur (SH) at the end, and are also called thiol or thioalcohol. Examples of such thiols include methyl mercaptan (CH3SH), ethyl mercaptan (C2H5SH), and 1-propanethiol (C3H7SH).

[0033] The above-mentioned esters are, for example, formates or acetates.

[0034] The above-mentioned ether is, for example, dimethyl ether ((CH3)2O), methyl ethyl ether (C2H5OCH3) or diethyl ether ((C2H5)2O).

[0035] The above-mentioned ketone is, for example, acetone ((CH3)2CO), methyl ethyl ketone (C2H5COCH3) or diethyl ketone ((C2H5)2CO).

[0036] The aldehyde mentioned above is, for example, acetaldehyde (CH3CHO), propionaldehyde (C2H5CHO), or butyraldehyde (C3H7CHO).

[0037] In the following description, an example is given in which the fluid separated by the separation device 2 is a mixed substance containing a plurality of gases (ie, a mixed gas).

[0038] The separation device 2 includes a separation membrane module 21, a supply unit 26, a first recovery unit 27, and a second recovery unit 28. The separation membrane module 21 includes a zeolite membrane composite 1, a storage container 22, and two sealing members 23. The zeolite membrane composite 1 and the sealing members 23 are housed within the storage container 22. The supply unit 26, the first recovery unit 27, and the second recovery unit 28 are disposed outside of and connected to the storage container 22.

[0039] Figure 2 It is a cross-sectional view of the zeolite membrane composite 1 . Figure 3 This is a cross-sectional view showing an enlarged portion of the zeolite membrane composite 1 . Figure 2 The seal 13, described later, is omitted from the illustration. The zeolite membrane composite 1 is a separation membrane composite comprising a porous support 11 and a zeolite membrane 12, which is a separation membrane, disposed on the support 11. The zeolite membrane 12 is a membrane formed by at least zeolite in a film-like manner on the surface of the support 11, and does not include a membrane simply obtained by dispersing zeolite particles within an organic membrane. Furthermore, the zeolite membrane 12 may comprise two or more zeolites having different structures and compositions. Figure 2 In FIG, the zeolite membrane 12 is depicted with a thick line. Figure 3 In FIG, parallel oblique lines are marked on the zeolite membrane 12. In addition, Figure 3 In FIG, the thickness of the zeolite membrane 12 is drawn thicker than the actual thickness.

[0040] It should be noted that a separation membrane complex other than the zeolite membrane complex 1 may be used in the separation device 2. An inorganic membrane composed of an inorganic substance other than zeolite or a membrane other than an inorganic membrane may be formed on the support 11 as a separation membrane in place of the zeolite membrane 12. Furthermore, a separation membrane in which zeolite particles are dispersed in an organic membrane may be used. In the following description, the separation membrane is assumed to be the zeolite membrane 12.

[0041] The support 11 is a porous member that is permeable to gas and liquid. Figure 2 In the example shown, the support body 11 is an integrally formed columnar main body with two sections respectively extending along the length direction (ie, Figure 2 An integral support body having multiple through holes 111 extending in the left and right directions. Figure 2 In the example shown, the support body 11 is substantially cylindrical, and each through hole 111 (ie, cell) has a substantially circular cross section perpendicular to the longitudinal direction. Figure 2 In FIG. 1 , the diameter of the through-hole 111 is drawn larger than the actual diameter, and the number of the through-holes 111 is drawn smaller than the actual number. The zeolite membrane 12 is formed on the inner surface of the through-hole 111, covering the substantially entire inner surface of the through-hole 111.

[0042] The length of the support 11 (ie, Figure 2 The length in the left-right direction of the support body 11 is, for example, 10 cm to 200 cm. The outer diameter of the support body 11 is, for example, 0.5 cm to 200 cm. The distance between the center axes of adjacent through holes 111 is, for example, 0.3 mm to 10 mm. The surface roughness (Ra) of the support body 11 is, for example, 0.1 μm to 5.0 μm, preferably 0.2 μm to 2.0 μm. It should be noted that the shape of the support body 11 can be, for example, honeycomb, flat, tubular, cylindrical, columnar or polygonal. When the shape of the support body 11 is tubular or cylindrical, the thickness of the support body 11 is, for example, 0.1 mm to 10 mm.

[0043] The material of the support 11 can be any material that is chemically stable during the process of forming the zeolite film 12 on the surface, and various substances (for example, ceramics or metals) can be used. In the present embodiment, the support 11 is formed of a ceramic sintered body. Examples of the ceramic sintered body selected as the material of the support 11 include: alumina, silica, mullite, zirconia, titania, yttrium trioxide, silicon nitride, silicon carbide, etc. In the present embodiment, the support 11 includes at least one of alumina, silica, and mullite.

[0044] The support 11 may include an inorganic binder. As the inorganic binder, at least one of titanium dioxide, mullite, sinterable alumina, silicon dioxide, glass frit, clay mineral, and sinterable cordierite may be used.

[0045] The average pore diameter of the support 11 is, for example, 0.01 μm to 70 μm, preferably 0.05 μm to 25 μm. The average pore diameter of the support 11 near the surface where the zeolite membrane 12 is to be formed is 0.01 μm to 1 μm, preferably 0.05 μm to 0.5 μm. For example, the average pore diameter can be measured using a mercury porosimeter, a pore size distribution meter, or a nano-size pore size distribution meter. Regarding the overall pore size distribution of the support 11, including the surface and interior, D5 is, for example, 0.01 μm to 50 μm, D50 is, for example, 0.05 μm to 70 μm, and D95 ​​is, for example, 0.1 μm to 2000 μm. The porosity of the support 11 near the surface where the zeolite membrane 12 is to be formed is, for example, 20% to 60%.

[0046] The support 11 has a multilayer structure in which, for example, multiple layers having different average pore diameters are stacked in the thickness direction. The average pore diameter and sintered particle size of the surface layer, including the surface on which the zeolite membrane 12 is to be formed, are smaller than the average pore diameter and sintered particle size of the layers other than the surface layer. The average pore diameter of the surface layer of the support 11 is, for example, 0.01 μm to 1 μm, preferably 0.05 μm to 0.5 μm. When the support 11 has a multilayer structure, the materials of each layer can be the above-mentioned materials. The materials of the multiple layers forming the multilayer structure may be the same or different.

[0047] The zeolite membrane 12 is a porous membrane with micropores. It can be used as a separation membrane to separate a specific substance from a fluid containing a mixture of multiple substances using a molecular sieving effect. Other substances are less likely to permeate the zeolite membrane 12 than the specific substance. In other words, the permeation rate of the other substance through the zeolite membrane 12 is less than that of the specific substance.

[0048] The thickness of the zeolite membrane 12 is, for example, 0.05 μm to 30 μm, preferably 0.1 μm to 20 μm, and more preferably 0.5 μm to 10 μm. A thicker zeolite membrane 12 improves separation performance. A thinner zeolite membrane 12 increases permeation rate. The surface roughness (Ra) of the zeolite membrane 12 is, for example, 5 μm or less, preferably 2 μm or less, more preferably 1 μm or less, and even more preferably 0.5 μm or less.

[0049] The type of zeolite comprising the zeolite membrane 12 is not particularly limited. To increase CO2 permeability and improve separation performance, the zeolite membrane 12 preferably has a pore structure with 8 or fewer oxygen rings. That is, the maximum number of ring members in the zeolite contained in the zeolite membrane 12 is 8 or fewer (e.g., 6 or 8). Here, an n-membered oxygen ring is defined as a ring structure consisting of n oxygen atoms forming the pore skeleton, each of which is bonded to a T atom (described later). Depending on the type of gas being treated, the maximum number of ring members in the zeolite may be greater than 8.

[0050] The zeolite membrane 12 is, for example, a DDR-type zeolite. In other words, the zeolite membrane 12 is a zeolite with the structural code "DDR" as specified by the International Zeolite Society. In this case, the zeolite constituting the zeolite membrane 12 has an intrinsic pore diameter of 0.36 nm x 0.44 nm, with an average pore diameter of 0.40 nm. The intrinsic pore diameter of the zeolite membrane 12 is smaller than the average pore diameter of the support 11.

[0051] The zeolite membrane 12 is not limited to DDR zeolite and may be zeolites having other structures. The zeolite membrane 12 may be, for example, AEI, AEN, AFN, AFV, AFX, BEA, CHA, DDR, ERI, ETL, FAU (X, Y), GIS, LEV, LTA, MEL, MFI, MOR, PAU, RHO, SAT, SOD, or other zeolites.

[0052] The zeolite membrane 12 includes, for example, silicon (Si). The zeolite membrane 12 may include, for example, any two or more of Si, aluminum (Al), and phosphorus (P). Zeolites constituting the zeolite membrane 12 include: zeolites in which the atoms (T atoms) located at the center of the oxygen tetrahedron (TO4) constituting the zeolite are solely Si; zeolites in which the T atoms include Si and Al; AlPO-type zeolites in which the T atoms include Al and P; SAPO-type zeolites in which the T atoms include Si, Al, and P; MAPSO-type zeolites in which the T atoms include magnesium (Mg), Si, Al, and P; and ZnAPSO-type zeolites in which the T atoms include zinc (Zn), Si, Al, and P. Some of the T atoms may be replaced by other elements.

[0053] When the zeolite membrane 12 contains Si atoms and Al atoms, the Si / Al ratio in the zeolite membrane 12 is, for example, 1 or greater and 100,000 or less. This Si / Al ratio is preferably 5 or greater, more preferably 20 or greater, and even more preferably 100 or greater, with the higher the ratio being more desirable. The Si / Al ratio in the zeolite membrane 12 can be adjusted by adjusting the ratio of the Si source and the Al source in the raw material solution described later. The zeolite membrane 12 may contain an alkali metal. The alkali metal is, for example, sodium (Na) or potassium (K).

[0054] The permeation rate of CO2 through the zeolite membrane 12 at 20°C to 400°C is, for example, 100 nmol / m 2 ·s·Pa or more. In addition, the CO2 permeation / N2 leakage ratio (permeation ratio) of the zeolite membrane 12 at 20°C to 400°C is, for example, 5 or more. The permeation and permeation ratio are values ​​when the CO2 partial pressure difference between the supply side and the permeation side of the zeolite membrane 12 is 1.5 MPa.

[0055] Here, an example of a manufacturing process for the zeolite membrane composite 1 is described. To manufacture the zeolite membrane composite 1, seed crystals for manufacturing the zeolite membrane 12 are first prepared. For example, a DDR-type zeolite powder is generated by hydrothermal synthesis, and seed crystals are obtained from this zeolite powder. The zeolite powder can be used directly as the seed crystals, or the powder can be processed by pulverization or other processes to obtain seed crystals.

[0056] Next, the porous support 11 is immersed in a solution containing dispersed seed crystals, thereby attaching the seed crystals to the support 11. Alternatively, the solution containing dispersed seed crystals is brought into contact with the portion of the support 11 where the zeolite membrane 12 is to be formed, thereby attaching the seed crystals to the support 11. In this manner, a support with seed crystals attached is produced. The seed crystals may be attached to the support 11 by other methods.

[0057] The support 11 with the seed crystal attached is immersed in a raw material solution. For example, the raw material solution is prepared by dissolving or dispersing a Si source and a structure-directing agent (hereinafter referred to as "SDA") in a solvent. The raw material solution can be prepared by using, for example, water or an alcohol such as ethanol. The SDA contained in the raw material solution can be, for example, an organic substance. For example, 1-adamantanamine can be used as the SDA.

[0058] Then, DDR type zeolite is grown using the seed crystals as nuclei by hydrothermal synthesis, thereby forming a DDR type zeolite membrane 12 on the support 11. The temperature during the hydrothermal synthesis is preferably 120 to 200° C. The hydrothermal synthesis time is preferably 6 to 100 hours.

[0059] After the hydrothermal synthesis is completed, the support 11 and zeolite membrane 12 are washed with pure water. The washed support 11 and zeolite membrane 12 are dried at, for example, 80°C. After drying, the zeolite membrane 12 is heated to almost completely burn and remove the SDA in the zeolite membrane 12, thereby opening up the micropores within the zeolite membrane 12. This results in the aforementioned zeolite membrane composite 1.

[0060] Figure 1In the example of the zeolite membrane complex 1 shown, sealing portions 13 are provided at both ends of the support body 11 in the longitudinal direction. The sealing portion 13 is a component that covers and seals the two end faces of the support body 11 in the longitudinal direction and the outer surface near the two end faces. The sealing portion 13 prevents gas from flowing in and out of the two end faces of the support body 11. The sealing portion 13 is formed of, for example, glass, resin or metal. The material and shape of the sealing portion 13 can be appropriately changed. It should be noted that both ends of each through hole 111 in the longitudinal direction are not covered by the sealing portion 13, and gas can flow in and out of the through hole 111 from these two ends.

[0061] Figure 1 In the separation membrane assembly 21, the storage container 22 is a cylindrical member, for example, which is roughly cylindrical. The storage container 22 can be in a shape other than cylindrical. The storage container 22 is a pressure-resistant container, formed of, for example, stainless steel or carbon steel. The length direction of the storage container 22 is roughly parallel to the length direction of the zeolite membrane complex 1. At one end of the length direction of the storage container 22 (i.e., Figure 1 A supply port 221 is provided at the left end of the container 22, and a first discharge port 222 is provided at the other end. A second discharge port 223 is provided on the side of the storage container 22. The supply port 221 is connected to the supply unit 26. The first discharge port 222 is connected to the first recovery unit 27. The second discharge port 223 is connected to the second recovery unit 28. The interior space of the storage container 22 is a sealed space isolated from the space surrounding the storage container 22.

[0062] Figure 1 In the example shown, the storage container 22 includes: a container body 224, and two cover portions 226. The container body 224 is a roughly cylindrical component having openings at both ends in the longitudinal direction. Two flange portions 225 are provided on the container body 224. The two flange portions 225 are respectively roughly annular plate-shaped parts extending from the container body 224 toward the radial outside around the above-mentioned two openings of the container body 224. The container body 224 and the two flange portions 225 are integrally connected components. The two cover portions 226 are fixed to the two flange portions 225 by means of bolts or the like in a state of covering the above-mentioned two openings of the container body 224. Accordingly, the two openings of the container body 224 are hermetically sealed. The above-mentioned supply port 221 is provided at Figure 1 The left side cover 226. The first outlet 222 is provided at Figure 1 The second discharge port 223 is provided at approximately the center of the container body 224 in the longitudinal direction.

[0063] The two sealing members 23 are disposed around the entire periphery of the zeolite membrane composite 1 between the outer surface of the zeolite membrane composite 1 and the inner surface of the storage container 22 near both ends in the longitudinal direction of the zeolite membrane composite 1 ( Figure 1In the example, it is between the outer peripheral surface of the zeolite membrane composite 1 and the inner peripheral surface of the container body 224.) Each sealing member 23 is formed of a gas-impermeable material. Figure 1 In the example of FIG, the sealing member 23 is annular, for example, an O-ring formed of a flexible resin. The material of the sealing member 23 is, for example, perfluoroelastomer (FFKM), nitrile rubber (NBR), fluororubber (FKM), styrene-butadiene rubber (SBR), or the like.

[0064] Each sealing member 23 is in close contact with the outer surface of the zeolite membrane composite 1 and the inner surface of the storage container 22 over its entire circumference. Figure 1 In the example shown, the sealing member 23 is in close contact with the outer surface of the sealing portion 13 and is indirectly in close contact with the outer surface of the support 11 via the sealing portion 13. The sealing member 23 is sealed against the outer surface of the zeolite membrane complex 1 and against the inner surface of the storage container 22, so that gas can hardly or completely pass through. In the separation membrane module 21, the sealing member 23 is used to ensure airtightness between the second discharge port 223 and the supply port 221 and the first discharge port 222. A lubricant is attached to the surface of the sealing member 23. The details of the lubricant are described below.

[0065] The supply unit 26 supplies the mixed gas to the interior space of the storage container 22 through the supply port 221. The supply unit 26 includes, for example, a blower or a pump that pressure-feeds the mixed gas toward the storage container 22. The blower or pump includes a pressure regulating unit that regulates the pressure of the mixed gas supplied to the storage container 22. The first recovery unit 27 and the second recovery unit 28 include, for example, storage containers that store the gas extracted from the storage container 22 or blowers or pumps that transfer the gas.

[0066] When performing mixed gas separation, the zeolite membrane complex 1 is prepared by preparing the above-mentioned separation device 2. Next, a mixed gas containing a plurality of gases having different permeabilities to the zeolite membrane 12 is supplied to the internal space of the storage container 22 using the supply unit 26. For example, the main components of the mixed gas are CO2 and N2. The mixed gas may contain gases other than CO2 and N2. The pressure (i.e., the introduction pressure) of the mixed gas supplied from the supply unit 26 to the internal space of the storage container 22 is, for example, 0.1 MPaA to 20.0 MPaA. The temperature for performing mixed gas separation is, for example, 10°C to 100°C.

[0067] The mixed gas supplied from the supply unit 26 to the storage container 22 is directed from the zeolite membrane composite 1 to the storage container 22 as indicated by arrow 251. Figure 1The left end of the through-hole 111 is introduced into each through-hole 111 of the support 11. The highly permeable gas in the mixed gas (e.g., CO2, hereinafter referred to as "highly permeable substance") permeates through the zeolite membrane 12 provided on the inner surface of each through-hole 111 and the support 11, and is then discharged from the outer surface of the support 11. In this way, the highly permeable substance is separated from the low-permeable gas (e.g., N2, hereinafter referred to as "low-permeable substance") in the mixed gas.

[0068] The gas (hereinafter referred to as "permeated material") that permeates the zeolite membrane composite 1 and is discharged from the outer surface of the support 11 is recovered by the second recovery unit 28 through the second discharge port 223 as indicated by arrow 253. The pressure of the gas recovered by the second recovery unit 28 through the second discharge port 223 (i.e., the permeation pressure) is, for example, approximately 1 atmosphere (0.101 MPaA).

[0069] In addition, the gas in the mixed gas other than the gas that permeates the zeolite membrane composite 1 (hereinafter referred to as "non-permeable substances") is discharged from each through hole 111 of the support body 11. Figure 1 The non-permeable material is discharged to the outside of the storage container 22 through the first discharge port 222 as indicated by arrow 252 and recovered by the first recovery unit 27. The pressure of the gas recovered by the first recovery unit 27 through the first discharge port 222 is, for example, substantially the same as the introduction pressure. The non-permeable material may include, in addition to the low-permeability materials described above, high-permeability materials that do not pass through the zeolite membrane 12.

[0070] Next, the details of the lubricant will be described. As described above, the lubricant adheres to the surface of the sealing member 23. A lubricant is a substance obtained by adding a solid such as a thickener (a chemical agent used to increase viscosity and emulsion stability) to a liquid lubricating oil. A lubricant is, for example, a fluorinated oil-based grease. An example of a lubricant is MOLYKOTE (registered trademark) HP-500 manufactured by DuPont Toray Specialty Materials.

[0071] The lubricant can be applied directly to the surface of the sealing component 23, or it can be applied to the outer surface of the zeolite membrane complex 1 or the inner surface of the storage container 22 that is in contact with the sealing component 23 and adhere to the surface of the sealing component 23. In one example, the lubricant adheres to substantially the entire surface of the sealing component 23. The lubricant can be attached to the area on the surface of the sealing component 23 that is in contact with the outer surface of the zeolite membrane complex 1 and the area that is in contact with the inner surface of the storage container 22. The lubricant is sandwiched between the outer surface of the sealing component 23 and the zeolite membrane complex 1 and between the sealing component 23 and the inner surface of the storage container 22. However, in the following description, even when the lubricant is sandwiched, the sealing component 23 is in contact with the outer surface of the zeolite membrane complex 1 and the sealing component 23 is in contact with the inner surface of the storage container 22.

[0072] The lubricant preferably has low volatility. The volatility of the lubricant can be evaluated by using the volatility of the lubricant when it is left at room temperature. For example, when the lubricant is taken from the product container of the lubricant and left at 25-30°C for 72 hours, the ratio of the mass reduction of the lubricant after 72 hours to the mass before the lubricant is left at rest (i.e., (mass reduction of the lubricant) / (mass of the lubricant before the lubricant is left at rest) × 100) is calculated as the volatility. The above volatility is, for example, less than 1%, preferably less than 0.5%, and more preferably less than 0.1%. Accordingly, it is possible to prevent substances volatilized from the lubricant at room temperature from adhering to the zeolite membrane 12 and causing a decrease in the separation performance of the zeolite membrane complex 1.

[0073] The lubricant preferably has thermal stability. The thermal stability of the lubricant can be evaluated by the mass reduction rate when the lubricant is heated under specified conditions. For example, when an unheated lubricant is heated at 100°C for 72 hours, the ratio of the mass reduction of the lubricant caused by heating to the mass before heating (i.e., (mass reduction of lubricant) / (mass of lubricant before heating)×100) is calculated as the mass reduction rate. At this time, it is preferred to heat only the lubricant, but it is also possible to cut out the sealing component 23 with a large amount of lubricant attached and heat the lubricant and the sealing component 23. When the lubricant and the sealing component 23 are heated, typically, since the mass of the sealing component 23 hardly changes due to the heating at the above temperature, the overall mass reduction of the lubricant and the sealing component 23 can also be set as the mass reduction of the lubricant. The mass reduction of the lubricant caused by heating can also be calculated by similarly heating other sealing components 23 from which the lubricant has been removed and measuring the mass reduction of the sealing component 23.

[0074] The mass reduction rate is, for example, 5% or less, preferably 3% or less, and more preferably 1% or less. This can prevent substances generated from the lubricant due to heating from adhering to the zeolite membrane 12 and causing a reduction in separation performance of the zeolite membrane composite 1.

[0075] The reduction in separation performance caused by substances generated from the lubricant during heating can be evaluated by heating the separation membrane module 21 under specified conditions and measuring the change in the permeation rate of a specified gas before and after heating. For example, a separation device 2 equipped with an unused separation membrane module 21 (unheated separation membrane module 21) is prepared. Next, a mixed gas is supplied to the separation device 2, and the permeation rate of a specified gas contained in the mixed gas that permeates through the zeolite membrane composite 1 (the amount recovered via the second discharge port 223, hereinafter referred to as "gas permeation rate") is measured. The separation membrane module 21 is then heated at 100°C for 72 hours with the supply port 221, first discharge port 222, and second discharge port 223 sealed and the storage container 22 sealed. After heating is completed, the gas permeation rate of the mixed gas in the separation device 2 is measured again.

[0076] Then, the ratio of the gas permeation rate of the zeolite membrane complex 1 after heating to the gas permeation rate of the zeolite membrane complex 1 before heating is calculated (i.e., (gas permeation rate after heating) / (gas permeation rate before heating)×100). It can be said that the higher the ratio, the more the reduction in separation performance is suppressed. In the separation membrane component 21, the ratio is, for example, 80% or more, preferably 85% or more, and more preferably 90% or more. The ratio is usually 100% or less. In one example, the above-mentioned gas that permeates through the zeolite membrane complex 1 is carbon dioxide (CO2) gas, but is not limited to this. When measuring the CO2 permeation rate, for example, a mixed gas of CO2 and N2 is used.

[0077] In the separation membrane module 21 , the position of the zeolite membrane composite 1 is maintained (held) relative to the storage container 22 by the sealing member 23 . Figure 1In the example shown, inside the storage container 22, the zeolite membrane complex 1 is not in contact with any component other than the sealing component 23. In addition, the outer surface at the two ends of the zeolite membrane complex 1, that is, the outer surface of the sealing portion 13, is a cylindrical surface flat in the longitudinal direction. In other words, no recessed portion or the like for holding the sealing component 23 is formed on the outer surface. Therefore, the relative position of the zeolite membrane complex 1 and the sealing component 23 is maintained by the friction between the outer surface of the zeolite membrane complex 1 (the supported surface 14 described later) and the surface of the sealing component 23. In addition, at the position opposite to the two ends of the zeolite membrane complex 1, the inner surface of the storage container 22 is a cylindrical surface flat in the longitudinal direction. That is, no recessed portion or the like for holding the sealing component 23 is formed on the inner surface. Therefore, the relative position of the sealing component 23 and the storage container 22 is maintained by the friction between the surface of the sealing component 23 and the inner surface of the storage container 22.

[0078] As explained above, Figure 1 In the separation membrane module 21 shown, the position of the zeolite membrane complex 1 relative to the storage container 22 is maintained by friction between the outer surface of the zeolite membrane complex 1 and the sealing member 23, and by friction between the sealing member 23 and the inner surface of the storage container 22. In the following description, the portion 14 ( Figure 1 In the example, the outer surface of the sealing portion 13 is referred to as the "supported surface 14," and the portion 24 of the inner surface of the storage container 22 that contacts the sealing member 23 is referred to as the "supporting surface 24." The supported surface 14 and the supporting surface 24 face each other with the sealing member 23 interposed therebetween. Figure 1 In the example of FIG, both the supported surface 14 and the supporting surface 24 are annular. In addition, when the zeolite membrane composite 1 is not provided with the sealing portion 13 , the supported surface 14 may be the surface of the support 11 .

[0079] As described above, in the separation membrane module 21, the mixed gas supplied from the supply port 221 is separated into a permeate that permeates the zeolite membrane composite 1 and is directed to the second discharge port 223, and a non-permeate that does not permeate the zeolite membrane composite 1 and is directed to the first discharge port 222. Furthermore, the airtightness between the second discharge port 223 and the supply port 221 and the first discharge port 222 is ensured by the sealing member 23.

[0080] Here, when vibration or shock is applied to the separation membrane assembly 21, if sliding occurs between the sealing member 23 and the supporting surface 24 or the supported surface 14, causing the zeolite membrane complex 1 or the sealing member 23 to move significantly relative to the storage container 22, the above-mentioned airtightness may not be maintained. In addition, the sealing member 23 may separate from the zeolite membrane complex 1, causing the zeolite membrane complex 1 and the storage container 22 to collide, thereby damaging the zeolite membrane complex 1. Therefore, even when vibration or shock is applied to the separation membrane assembly 21, it is preferable that the relative positions of the zeolite membrane complex 1 and the sealing member 23 with respect to the storage container 22 are maintained, and the zeolite membrane complex 1 is appropriately supported within the storage container 22.

[0081] To prevent the zeolite membrane composite 1 and the sealing member 23 from moving relative to the housing 22 due to vibration or impact on the separation membrane module 21, the friction force F1 between the sealing member 23 and the supported surface 14 and the supporting surface 24 must be greater than the force F2 (hereinafter referred to as "impact force F2") applied in the longitudinal direction due to vibration or impact. Here, the friction force F1 is expressed by Equation 1, and the impact force F2 is expressed by Equation 2.

[0082] (Mathematical formula 1)

[0083] Friction force F1 = (static friction coefficient) × (vertical resistance due to seal [N]) = (static friction coefficient) × (compression force of seal [N]) = (static friction coefficient) × (compression force of seal per meter [N / m]) × (total contact length of seal [m])

[0084] (Mathematical formula 2)

[0085] Impact force F2 = (mass of zeolite membrane composite [kg]) × (vibration acceleration [m / s 2 ])

[0086] Based on this, the condition under which the zeolite membrane composite does not move when a certain vibration acceleration is applied is expressed by Mathematical Formula 3.

[0087] (Mathematical formula 3)

[0088] (Static friction coefficient) × (Compression force of the sealing member per 1 m [N / m]) × (Total contact length of the sealing member [m]) / (Mass of the zeolite membrane composite [kg]) > (Vibration acceleration [m / s 2 ])

[0089] In Equations 1 and 3, the "compression force per meter of the sealing member" is determined by the hardness, wire diameter, and compression margin of the sealing member 23. For example, the values ​​published by the sealing member manufacturer can be used, or the value can be determined experimentally. In Equations 1 and 3, the "total contact length of the sealing member" is the length of contact between the sealing member and the supported surface or the supporting surface. For example, if the sealing member is an O-ring, the contact length between the sealing member and the supported surface 14 is calculated using Equation 4.

[0090] (Mathematical formula 4)

[0091] Total contact length of the sealing component [m] = (inner diameter of the sealing component [m]) × π × (number of sealing components)

[0092] The compression allowance of the sealing member 23 is determined by the JIS standard. In the examples described below, a sealing member with P-180, A50, a compression allowance of 0.65, and a linearity of 8.4 is used. In addition, in Mathematical Formulas 2 and 3, "vibration acceleration" is determined by the magnitude of the vibration. In the examples described below, a value of 0.7 to 1 m / s, which corresponds to 97 to 100 dB, is set. 2 When the "vibration acceleration" is determined to be a specified value based on the specifications required for the separation membrane assembly 21, the greater the "static friction coefficient", the greater the "compression force of the sealing component" (the value obtained by multiplying the "compression force of the sealing component per 1m" by the "total contact length of the sealing component"), or the smaller the "mass of the zeolite membrane complex", the more difficult it is for the zeolite membrane complex 1 and the sealing component 23 to move relative to the storage container 22. Therefore, it can be said that the greater the value obtained by multiplying the "static friction coefficient" by the "compression force of the sealing component" and then dividing it by the "mass of the zeolite membrane complex", the more resistant the separation membrane assembly 21 is to vibration and impact, and the easier it is to maintain a state of ensuring airtightness.

[0093] In order to properly support the zeolite membrane complex 1 within the storage container 22 and maintain the airtightness provided by the sealing member 23 even after vibration or impact is applied, the value obtained by multiplying the static friction coefficient between the sealing member 23 and the supported surface 14 (hereinafter referred to as the "first static friction coefficient") by the compressive force [N] of the sealing member, divided by the mass [kg] of the zeolite membrane complex 1, is, for example, greater than 0.7, preferably greater than 0.9, and more preferably greater than 1.0. Similarly, the value obtained by multiplying the static friction coefficient between the sealing member 23 and the supporting surface 24 (hereinafter referred to as the "second static friction coefficient") by the compressive force [N] of the sealing member, divided by the mass [kg] of the zeolite membrane complex 1, is, for example, greater than 0.7, preferably greater than 0.9, and more preferably greater than 1.0.

[0094] For example, if airtightness is maintained between the second discharge port 223 and the supply port 221 and the first discharge port 222 after a predetermined vibration or shock is applied, the zeolite membrane complex 1 is considered to be properly supported in the storage container 22. To confirm airtightness, for example, the inspection method described in International Publication No. WO2018 / 180095 (the above-mentioned document 5) can be used. In this method, inspection gas is supplied from the supply port 221 while the first discharge port 222 is closed. The dynamic molecular diameter of the inspection gas is larger than the pore diameter of the zeolite membrane 12. When the inspection gas in the storage container 22 reaches a predetermined pressure, the supply port 221 is closed. Next, the leakage amount of the inspection gas at the second discharge port 223 is obtained. The leakage amount of the inspection gas is calculated based on, for example, the pressure change of the inspection gas on the supply port 221 side. If the leakage amount of the inspection gas is less than a predetermined threshold value, it is determined that airtightness is ensured by the sealing component 23; if the leakage amount is greater than the threshold value, it is determined that airtightness is not ensured. It should be noted that, strictly speaking, the leakage of the inspection gas includes not only the leakage from the sealing member 23 but also the leakage from membrane defects in the zeolite membrane 12. Therefore, the leakage used for determination may be the leakage excluding the leakage from membrane defects. The leakage from membrane defects is calculated based on a calculation formula obtained, for example, through experimentation.

[0095] For example, a sheet-like or plate-like component and an actual sealing component 23 made of the same material and having the same surface state (surface roughness (Ra)) as the zeolite membrane complex 1 and the storage container 22 are used to measure the first and second static friction coefficients. In the separation membrane assembly 21, the surface roughness (Ra) of the surface of the sealing component 23 is, for example, 1 μm to 100 μm, preferably 5 μm to 20 μm. The surface roughness (Ra) of the supported surface 14 of the zeolite membrane complex 1 is, for example, 5 μm to 100 μm, preferably 10 μm to 50 μm. The surface roughness (Ra) of the supporting surface 24 of the storage container 22 is, for example, 1 μm to 50 μm, preferably 5 μm to 20 μm. The surface roughness is measured using, for example, a laser microscope.

[0096] Figure 4 This is a diagram showing how the second static friction coefficient between the sealing member 23 and the support surface 24 of the storage container 22 is measured. Figure 4In the example, a plate member 91 made of the same material and having the same surface condition as the support surface 24 (container body 224) of the storage container 22 is placed on a predetermined horizontal plane. In addition, the actual sealing member 23 is overlapped on the plate member 91. At this time, the surface of the sealing member 23 in contact with the plate member 91 is coated with a lubricant that is the same as the lubricant used in the separation membrane assembly 21. The amount of lubricant applied is preferably 0.01g to 1g. A weight 93 (for example, a weight with a mass of more than 1kg) is placed on the sealing member 23. The sealing member 23 and the weight 93 can be fixed as needed. In addition, a dynamometer 94 is connected to the sealing member 23 (or the weight 93 fixed to the sealing member 23). Then, the sealing member 23 is pulled in the horizontal direction with the help of the dynamometer 94, and the force F[N] (hereinafter referred to as the "force at the yield point") obtained when the sealing member 23 moves is measured. The second static friction coefficient μ is solved by mathematical formula 5.

[0097] (Mathematical formula 5)

[0098] μ = F / {(mass of sheet [kg] + mass of weight [kg]) × acceleration due to gravity}

[0099] Figure 4 In the example, the second static friction coefficient was measured using a component equivalent to the storage container 22. However, as mentioned above, the first static friction coefficient can also be measured using a component equivalent to the zeolite membrane complex 1. Alternatively, the first and second static friction coefficients can be measured using cut pieces obtained by cutting the zeolite membrane complex 1 and the storage container 22, respectively. If a large-scale measurement device is available, the first and second static friction coefficients can be measured while the separation membrane module 21 is intact (uncut). The static friction coefficient does not depend on the area of ​​the contact surface, so all measurements yield the same result.

[0100] Figure 5 This is a diagram showing how the first static friction coefficient between the sealing member 23 and the supported surface 14 of the zeolite membrane composite 1 is measured. Figure 5 In the example shown, the actual sealing member 23 is placed on the platform 95. The sealing member 23 can be fixed to the platform 95 as needed. A lubricant is applied to the sealing member 23. Alternatively, a cut piece (e.g., with a mass of 1 kg or more) obtained by cutting the zeolite membrane composite 1 is placed on the sealing member 23 so that only the sealing portion 13 is in contact. Figure 5In the figure, the cut piece of the zeolite membrane complex 1 is marked with the same symbol as the zeolite membrane complex 1. A weight can be placed on the cut piece as needed, and the cut piece and the weight can be fixed. Then, the cut piece is pulled in the horizontal direction with the help of the dynamometer 94, and the force (force at the yield point) F [N] obtained when the cut piece moves is measured. The first static friction coefficient μ is solved in the same way as in Mathematical Formula 5. The same is true for the case where the cut piece obtained by cutting the storage container 22 is used for measurement.

[0101] When installing the zeolite membrane complex 1 in the storage container 22, for example, the zeolite membrane complex 1 is placed in the container body 224 with the lid 226 removed, and the sealing member 23 is inserted between the inner surface (supporting surface 24) of the container body 224 and the outer surface (supported surface 14) of the zeolite membrane complex 1 through the openings at both ends of the container body 224 in the longitudinal direction. Then, the lid 226 is attached to the container body 224.

[0102] In addition, in the separation membrane assembly 21, the sealing component 23 deteriorates depending on the type of mixed gas, temperature, etc., and therefore, the sealing component 23 needs to be replaced regularly. Sometimes, the separation membrane assembly 21 is disassembled for maintenance. In this case, first, the cover 226 is removed from the container body 224. Then, the sealing component 23 is pulled out from between the inner surface (supporting surface 24) of the container body 224 and the outer surface (supported surface 14) of the zeolite membrane complex 1 through the openings at both ends of the container body 224. Accordingly, the zeolite membrane complex 1 is removed from the storage container 22.

[0103] In order to easily install and remove the zeolite membrane complex 1 relative to the storage container 22, the first static friction coefficient between the sealing component 23 and the supported surface 14 is, for example, less than 0.5, preferably less than 0.4, and more preferably less than 0.3. In this case, between the sealing component 23 and the supported surface 14, the friction force F1 (maximum static friction force) is, for example, less than 250N, preferably less than 200N, and more preferably less than 150N. Similarly, the second static friction coefficient between the sealing component 23 and the supporting surface 24 is, for example, less than 0.5, preferably less than 0.4, and more preferably less than 0.3. In this case, between the sealing component 23 and the supporting surface 24, the friction force F1 is, for example, less than 250N, preferably less than 200N, and more preferably less than 150N.

[0104] As described above, in the separation membrane module 21, a sealing member 23 with lubricant adhered to its surface is provided between the supporting surface 24 provided within the storage container 22 and the supported surface 14 of the zeolite membrane complex 1. Furthermore, the first static friction coefficient between the sealing member 23 and the supported surface 14 and the second static friction coefficient between the sealing member 23 and the supporting surface 24 are 0.5 or less. Furthermore, the value obtained by multiplying the first and second static friction coefficients by the compressive force [N] of the sealing member 23 and dividing the result by the mass [kg] of the zeolite membrane complex 1 is greater than 0.7. Consequently, even when subjected to vibration or impact, the zeolite membrane complex 1 can be properly supported within the storage container 22. Furthermore, the zeolite membrane complex 1 can be easily installed and removed from the storage container 22. As a result, assembly and maintenance of the separation membrane module 21 can be easily performed, thereby improving the productivity and maintainability of the separation membrane module 21.

[0105] Furthermore, when the separation membrane module 21 was heated at 100°C for 72 hours, the ratio of the gas permeation rate of the zeolite membrane composite 1 after heating to the gas permeation rate of the zeolite membrane composite 1 before heating was 80% or greater. This provides a separation membrane module 21 in which degradation of separation performance due to the lubricant is suppressed. Furthermore, the mass reduction rate of the lubricant when heated at 100°C for 72 hours was 5% or less. This further suppresses degradation of the separation performance of the separation membrane module 21.

[0106] Next, an embodiment of a separation membrane assembly is described. Here, in the production of a zeolite membrane complex, first, a monolithic support is prepared. The diameter of the support is 180 mm and the total length is 1000 mm. A sealing portion is formed of glass on the two end faces in the longitudinal direction of the support and the outer surface near the two end faces. In addition, based on the method for producing DDR type zeolite described in Japanese Patent Application Laid-Open No. 2004-83375 (the above-mentioned document 3), a DDR type zeolite crystal powder is produced and used as a seed crystal. The seed crystals are dispersed in water, and then the coarser particles are removed to produce a seed crystal dispersion. Next, based on the method described in International Publication No. WO2011 / 105511 (the above-mentioned document 4), a zeolite membrane complex having a diameter of 180 mm and a total length of 1000 mm is produced.

[0107] In addition, a sealing component and a storage container are prepared. The sealing component is an O-ring made of rubber with a Shore hardness of A50, an inner diameter (diameter) of 179.5 mm, and a wire diameter (diameter) of 8.4 mm (P-180 in the P standard). In addition, the diameter of the inner surface of the storage container is designed in accordance with JIS B2401 so that the compression margin of the sealing component is 0.65 mm. Then, the zeolite membrane complex is installed in the storage container using the sealing component to obtain a separation membrane assembly. At this time, in the separation membrane assemblies of Examples 1 to 3, a lubricant is applied to the surface of the sealing component. The lubricant used in Example 1 is MOLYKOTE (registered trademark) HP-500 manufactured by DuPont Toray Specialty Materials, the lubricant used in Example 2 is MOLYKOTE (registered trademark) high vacuum grease, and the lubricant used in Example 3 is Sumilon 2250 spray manufactured by Sumi Mining Lubricants. In the separation membrane assembly of Comparative Example 1, no lubricant is applied to the sealing component.

[0108] (Measurement of the First Static Friction Coefficient between the Zeolite Membrane Composite and the Sealing Member)

[0109] On the sealing component, the cut piece is overlapped in such a manner that the supported surface of the cut piece obtained by cutting the zeolite membrane complex contacts the sealing component. At this time, the surface where the sealing component and the supported surface of the zeolite membrane complex contact each other is coated with the same lubricant as the lubricant used in Examples 1 to 3. In Comparative Example 1, no lubricant is applied to this surface. Then, the cut piece is pulled in the horizontal direction with the help of a dynamometer, and the force F[N] at the yield point is measured. The first static friction coefficient is solved using the above-mentioned mathematical formula 5. Table 1 shows the first static friction coefficient.

[0110] [Table 1]

[0111]

[0112] The lubricants used in Examples 1 to 3 all gave a first static friction coefficient of 0.25 or less. In contrast, in Comparative Example 1 in which no lubricant was used, the first static friction coefficient exceeded 0.7.

[0113] (Measurement of the Second Static Friction Coefficient Between the Storage Container and the Sealing Member)

[0114] A sealing component is overlapped on a plate component (100×100 mm) made of the same material and formed in the same surface state as the container body (support surface) of the storage container. At this time, the surface of the sealing component in contact with the plate component is coated with a lubricant that is the same as the lubricant used in Examples 1 to 3. In Comparative Example 1, no lubricant is applied to this surface. Next, a weight with a mass of 1.2 kg is placed on the sealing component and fixed with double-sided tape. Then, the weight is pulled in the horizontal direction with the help of a dynamometer, and the force F [N] at the yield point is measured. The second static friction coefficient is solved using the above-mentioned mathematical formula 5. Table 2 shows the second static friction coefficient.

[0115] [Table 2]

[0116]

[0117] The lubricants used in Examples 1-3 all achieved a second static friction coefficient of 0.35 or less. In contrast, in Comparative Example 1, which did not use a lubricant, the second static friction coefficient exceeded 0.7. In this test, both the first and second static friction coefficients in Examples 1-3 were 0.5 or less. However, for maintainability, a value of 0.5 or less for either is sufficient.

[0118] (Evaluation of separation performance before and after heating)

[0119] A mixed gas of carbon dioxide (CO2) and nitrogen (N2) (the volume ratio of each gas is 50:50, and the partial pressure of each gas is 0.2 MPa) is introduced into the separation membrane components of Examples 1 to 3 and Comparative Example 1, and the permeation flow rate of the gas passing through the zeolite membrane complex is measured using a mass flow meter. In addition, the gas passing through the zeolite membrane complex is subjected to component analysis by gas chromatography to obtain the CO2 concentration in the gas. Then, the permeation flow rate of the gas is multiplied by the CO2 concentration to determine the CO2 permeation amount. Next, the supply port, the first discharge port, and the second discharge port of the storage container (see Figure 1 The separation membrane module was heated at 100°C for 72 hours with the container sealed with the cap (see symbols 221 to 223). The CO2 permeation rate was then determined in the same manner as before heating, and the ratio [%] of the CO2 permeation rate after heating relative to the CO2 permeation rate before heating was calculated. Table 3 shows the ratio of the CO2 permeation rate after heating relative to the CO2 permeation rate before heating.

[0120] [Table 3]

[0121]

[0122] In the separation membrane modules of Examples 1, 2, and Comparative Example 1, the ratio of the CO 2 permeation after heating to the CO 2 permeation before heating was 85% or more, whereas in the separation membrane module of Example 3, the ratio was 45%.

[0123] (Evaluation of thermal stability of lubricants)

[0124] Approximately 10 to 30 mg of the lubricant used in Examples 1 to 3 was taken and subjected to thermogravimetric (TG) analysis to determine the mass reduction rate. The thermogravimetric measurement was performed using a Bruker TG-DTA2000SA. The measurement conditions were: atmosphere: N2 2200 ml / min, maximum temperature: 100°C, heating rate: 100°C / h, and hold at 100°C for 72 hours. The mass reduction rate was determined as the ratio of the mass reduction due to heating to the mass of the lubricant before heating. Table 4 shows the mass reduction rates of the lubricants.

[0125] [Table 4]

[0126]

[0127] The mass reduction rate of the lubricants used in Examples 1 and 2 was 1.0% or less, whereas the mass reduction rate of the lubricant used in Example 3 was greater than 29%.

[0128] (Evaluation of Lubricant Volatility)

[0129] Approximately 10 to 30 mg of the lubricant used in Examples 1 to 3 was taken from the product container and allowed to stand at 25 to 30°C for 72 hours. The ratio of the mass loss after standing to the mass of the lubricant before standing was calculated as the volatility. Table 5 shows the volatility of the lubricants.

[0130] [Table 5]

[0131]

[0132] The lubricants used in Examples 1 and 2 had a volatility of 0.01% or less, whereas the lubricant used in Example 3 had a volatility of more than 23%.

[0133] (Evaluation of airtightness before and after vibration test)

[0134] Three zeolite membrane composites of varying weights were prepared and mounted in a storage container using a sealing member to produce a separation membrane assembly. In Examples 1-1, 1-2, and Comparative Example 2, the sealing member was coated with the lubricant of Example 1, while in Examples 2-1, 2-2, and 2-3, the sealing member was coated with the lubricant of Example 2. Furthermore, in Examples 3-1, 3-2, and 3-3, the sealing member was coated with the lubricant of Example 3, while in Comparative Examples 1-1, 1-2, and 1-3, no lubricant was applied to the sealing member. Of the three zeolite membrane composites, the one with the smallest weight was used in Examples 1-1, 2-1, 3-1, and Comparative Example 1-1; the one with the second smallest weight was used in Examples 1-2, 2-2, 3-2, and Comparative Example 1-2; and the one with the largest weight was used in Comparative Example 2, Examples 2-3, 3-3, and Comparative Example 1-3.

[0135] First, the air tightness of the separation membrane assembly is checked using an inspection gas. As mentioned above, the inspection method is the same as the inspection method described in International Publication No. WO2018 / 180095 (the above-mentioned document 5). Before the vibration test, it was confirmed that the air tightness of all separation membrane assemblies was ensured by the sealing components. Next, the separation membrane assembly was placed on a large vibration device and vibration acceleration levels of 97, 99, and 100 dB and accelerations of 0.71, 0.89, and 1.00 m / s were applied. 2 Vibration. Then, the airtightness of the separation membrane assembly was confirmed again. Table 6 shows the airtightness after the vibration test and the value of (static friction coefficient × sealing component compression force) / separation membrane complex mass. It should be noted that in Table 6, in the "First static friction coefficient" and "Second static friction coefficient" columns, the static friction coefficient obtained for each type of lubricant (including "none") (refer to Table 1 and Table 2) is 0.5 or less. The case where the static friction coefficient is greater than 0.5 is marked with ×.

[0136] [Table 6]

[0137]

[0138] In the "Airtightness after vibration test" column of Table 6, ○ indicates that airtightness is ensured, and × indicates that airtightness cannot be ensured. In addition, the "(static friction coefficient × sealing component compression force) / separation membrane complex mass" column shows the value obtained by multiplying the static friction coefficient by the compression force of the sealing component [N] and then dividing it by the mass [kg] of the zeolite membrane complex. As "(static friction coefficient × sealing component compression force) / separation membrane complex mass", the values ​​of (static friction coefficient × sealing component compression force) / separation membrane complex mass are respectively calculated based on the first static friction coefficient of Table 1 and the second static friction coefficient of Table 2 obtained for each type of lubricant (including "none"), and the smaller of the two values ​​is recorded. In all embodiments and separation membrane assemblies of comparative examples except Comparative Example 2, airtightness was still ensured after the vibration test with a vibration acceleration level of 97 dB. In actual use environment, due to contact with gases of various temperatures and pressures, the conditions of this test are different. However, the impact value applied in this test is determined by taking these differences into consideration. If airtightness can be ensured in this test, it is believed that no dislocation will occur even under the use environment. Therefore, it is believed that if the value obtained by multiplying the first and second static friction coefficients by the compression force [N] of the sealing component and then dividing by the mass [kg] of the zeolite membrane complex is greater than 0.7, the zeolite membrane complex is still properly supported in the storage container even after the 97dB vibration test. From the viewpoint of maintaining airtightness even under greater vibration, the value of (static friction coefficient × sealing component compression force) / separation membrane complex mass is preferably 0.9 or more, more preferably 1.0 or more.

[0139] The above-mentioned separation membrane module 21 can be modified in various ways.

[0140] According to the design of the separation membrane module 21, Figure 1 The inner surface of the storage container 22 is provided with an annular recess for accommodating the sealing member 23. In this case, since the sealing member 23 is held in this recess, in order to properly support the zeolite membrane complex 1 in the storage container 22 and to facilitate installation and removal of the zeolite membrane complex 1 from the storage container 22, it is important that the first static friction coefficient between the sealing member 23 and the supported surface 14 of the zeolite membrane complex 1 is 0.5 or less, and that the value obtained by multiplying the first static friction coefficient by the compressive force [N] of the sealing member and dividing the result by the mass [kg] of the zeolite membrane complex 1 is greater than 0.7.

[0141] Similarly, an annular recess for accommodating the sealing member 23 may be provided on the outer surface of the zeolite membrane complex 1. In this case, in order to retain the sealing member 23 in the recess, it is important that the second static friction coefficient between the sealing member 23 and the supporting surface 24 of the storage container 22 is 0.5 or less, and the value obtained by multiplying the second static friction coefficient by the compressive force [N] of the sealing member and dividing it by the mass [kg] of the zeolite membrane complex 1 is greater than 0.7. As explained above, it is important that the static friction coefficient between the supported surface 14 and the surface of the supporting surface 24 that is not provided with the recess for accommodating the sealing member 23 and the sealing member 23 is 0.5 or less, and the value obtained by multiplying the static friction coefficient by the compressive force [N] of the sealing member 23 and dividing it by the mass [kg] of the separation membrane complex (the zeolite membrane complex 1 in the above description) is greater than 0.7. In other words, in the separation membrane module 21, the first static friction coefficient between the sealing member 23 and the supported surface 14 of the zeolite membrane complex 1, and / or the second static friction coefficient between the sealing member 23 and the supporting surface 24 of the storage container 22, is 0.5 or less. The value obtained by multiplying the first static friction coefficient and / or the second static friction coefficient by the compressive force [N] of the sealing member and dividing the result by the mass [kg] of the separation membrane complex is greater than 0.7. If the above conditions are met, the application of lubricant to the sealing member 23 may be omitted.

[0142] Figure 1 In the separation membrane module 21, the support surface 24 is a portion of the inner surface of the container body 224 of the storage container 22. However, for example, Figure 6 As shown, a substantially cylindrical support portion 229 fixed to the storage container 22 may also be provided, and the annular outer surface (or inner surface) provided on the support portion 229 is the support surface 24. In addition, Figure 1 In the example shown in FIG. 1 , the supported surface 14 is a portion of the outer surface of the zeolite membrane composite 1 . However, for example, the supported surface 14 may be a portion of the outer surface of the zeolite membrane composite 1 . Figure 6 Like the zeolite membrane composite 1 of FIG. 1 , a tubular support 11 is used, and the inner surface of the support 11 serves as a supported surface 14 . Figure 6 In the example, the inner surface of the support 11 faces the annular outer surface of the support portion 229 , and the annular sealing member 23 is in close contact with both, thereby supporting the zeolite membrane composite 1 in the storage container 22 .

[0143] In addition to the support 11 and the zeolite membrane 12, the zeolite membrane composite 1 may further include a functional film or a protective film laminated on the zeolite membrane 12. Such functional films and protective films may be inorganic films such as zeolite membranes, silicon dioxide films, or carbon films, or organic films such as polyimide films or organosilicon films. Furthermore, the functional film and protective film laminated on the zeolite membrane 12 may contain a substance that readily adsorbs specific molecules such as CO2.

[0144] The separation membrane module 21 can be used to separate substances other than the substances exemplified in the above description from a mixed substance.

[0145] The configurations in the above-described embodiment and various modifications may be appropriately combined as long as they do not contradict each other.

[0146] While the invention has been described and illustrated in detail, the above description is illustrative and not restrictive, and it can be understood that numerous modifications and variations can be employed without departing from the scope of the invention.

[0147] Industrial applicability

[0148] The separation membrane module of the present invention can be used for separation of various fluids.

[0149] Explanation of symbols

[0150] 1 Zeolite membrane complex

[0151] 11 Support

[0152] 12 Zeolite membrane

[0153] 14 Supported surface

[0154] 21 Separation membrane components

[0155] 22 Storage Containers

[0156] 23 Sealing parts

[0157] 24 Support surface

[0158] 224 Container body

Claims

1. A separation membrane module, wherein: have: A separation membrane complex comprising a support and a separation membrane disposed on the support; a storage container for storing the separation membrane complex; and a sealing member that is in close contact with a supporting surface provided inside the storage container and a supported surface of the separation membrane complex; The first static friction coefficient between the sealing component and the supported surface and / or the second static friction coefficient between the sealing component and the supporting surface is 0.5 or less. A value obtained by multiplying the first static friction coefficient and / or the second static friction coefficient by the compressive force of the sealing member and then dividing by the mass of the separation membrane complex is greater than 0.7, where the unit of the compressive force is N and the unit of the mass is kg.

2. The separation membrane module according to claim 1, wherein When heated at 100° C. for 72 hours, the ratio of the gas permeation rate of the separation membrane complex after heating to the gas permeation rate of the separation membrane complex before heating is 80% or more.

3. The separation membrane module according to claim 1 or 2, wherein A lubricant is applied to the surface of the sealing member.

4. The separation membrane module according to claim 3, wherein The mass reduction rate of the lubricant when the lubricant is heated at 100° C. for 72 hours is 5% or less.

5. The separation membrane module according to claim 1 or 2, wherein The support surface is a portion of the inner surface of the main body of the storage container. The supported surface is a portion of the outer surface of the separation membrane complex.

6. The separation membrane module according to claim 1 or 2, wherein The separation membrane is a zeolite membrane.

7. The separation membrane module according to claim 6, wherein The zeolite membrane has a pore structure with an 8-membered oxygen ring or less.

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