Operating method of separation apparatus and separation apparatus

Abstract

This method for operating a separation device using a separation membrane comprises: a process (step S12) for performing normal operation in which a mixed gas including a plurality of kinds of gases is supplied to the separation membrane at a fixed set pressure, whereby a substance in the mixed gas, the substance having high permeability through the separation membrane, is separated from other substances; and a process (step S11) for performing high-pressure processing for supplying the mixed gas to the separation membrane at a higher pressure than the set pressure either when the supply of the mixed gas to the separation membrane is initiated before the normal operation or in middle of the normal operation. By doing so, it is possible to remove an unnecessary substance adhered to the separation membrane and easily improve the permeation performance of the separation membrane.

Description

[Technical Field] 【0001】 This invention relates to a method for operating a separation apparatus and to a separation apparatus. [Reference to related applications] This application claims priority from Japanese Patent Application JP2022-92971, filed on 8 June 2022, and all disclosures of said application are incorporated herein. [Background technology] 【0002】 Conventionally, methods to improve the permeability performance of separation membranes have been investigated. Japanese Patent Publication No. 2012-236123 (Reference 1) discloses a method to obtain high carbon dioxide permeability by removing the crystalline water of a FAU-type zeolite membrane by heating and drying it at a temperature of 100 to 600°C, and then maintaining the dry state. International Publication No. 2018 / 180210 (Reference 2) discloses a method for regenerating zeolite membranes. In this method, a zeolite membrane in contact with a hydrocarbon mixture is pressurized while exposed to an inert gas atmosphere, and then the atmosphere is heated. In the method for regenerating a separation membrane module described in Japanese Patent Publication No. 2018-183756 (Reference 3), a raw material mixed gas is supplied to the separation membrane module to separate it into permeable gas and non-permeable gas, and the permeable gas is supplied to a separation membrane module where the supply of raw material mixed gas has been stopped, or to another separation membrane module, thereby removing impurities attached to the hollow fiber membrane. 【0003】 Incidentally, separation membranes are usually transported from the time they are manufactured until they are actually used. Furthermore, they may be stored for long periods before use. During transport and long-term storage, unwanted substances such as moisture and hydrocarbon components in the air can adhere to the separation membrane, potentially clogging some of its pores and reducing its permeability. As in Reference 1, if these unwanted substances are removed by heating, a heater is required. Also, high-temperature heating may shorten the lifespan of the separation membrane. As in Reference 2, if heating or pressurizing is performed using an inert gas, a heater is required, similar to the above, and the preparation of the inert gas is also necessary. As in Reference 3, if the separation membrane is regenerated using the permeate gas that has passed through it, two lines (series) containing the separation membrane are required, resulting in larger equipment and increased space and cost. [Overview of the project] 【0004】 The present invention aims to easily improve the permeability performance of separation membranes. 【0007】 manner 1 The invention relates to a method for operating a separation apparatus using a separation membrane, comprising the steps of: performing normal operation in which a mixed gas containing multiple types of gases is supplied to the separation membrane at a constant set pressure to separate substances in the mixed gas, which have high permeability to the separation membrane, from other substances; and performing high-pressure treatment in which the mixed gas is supplied to the separation membrane at a pressure higher than the set pressure at the start of supplying the mixed gas to the separation membrane before the normal operation, or during the normal operation, wherein the relationship between the ratio A of the applied pressure to the burst pressure and the lifetime L at the applied pressure is log 10 L=alog 10 The values ​​of a and b in the expression A+b are determined in advance, and the life consumption rate [%] in one high-pressure treatment obtained by substituting the ratio of the pressure during the high-pressure treatment to the burst pressure for A in the following equation using a and b, and substituting the time of the high-pressure treatment for t, is 0.1% or less. 【0008】 【number】 【0009】 According to the present invention, unwanted substances adhering to the separation membrane can be removed, and the permeability performance of the separation membrane can be easily improved. The invention of embodiment 2 is a method for operating the separation apparatus of embodiment 1, wherein the mixed gas is supplied to the separation membrane via a supply pipe, and the high-pressure treatment is performed by adjusting the opening degree of a control valve provided in the supply pipe. The invention of embodiment 3 is a method for operating the separation apparatus of embodiment 1 or 2, wherein the set pressure is 0.1 MPaG to 8 MPaG, and the pressure during high-pressure processing is 10 times or less the set pressure. 【0010】 The invention of embodiment 4 is a method for operating a separation apparatus according to any one of embodiments 1 to 3, wherein the high-pressure processing time is 0.1 seconds to 10,000 seconds. 【0011】 The invention of embodiment 5 is a method for operating any one of the separation apparatuses of embodiments 1 to 4, wherein the separation membrane is a zeolite membrane. 【0012】 The invention of embodiment 6 is a method for operating the separation apparatus of embodiment 5, wherein the maximum number of rings of the zeolite constituting the zeolite membrane is 8. 【0013】 manner 7 The invention relates to a separation apparatus comprising: a separation membrane; a supply unit that supplies a mixed gas containing multiple types of gases to the separation membrane to separate substances in the mixed gas, which have high permeability to the separation membrane, from other substances; and a control unit that controls the supply unit to perform normal operation in which the mixed gas is supplied to the separation membrane at a constant set pressure, and performs high-pressure processing in which the mixed gas is supplied to the separation membrane at a pressure higher than the set pressure at the start of supplying the mixed gas to the separation membrane before the normal operation, or during the normal operation, and the relationship between the ratio A of the applied pressure to the burst pressure and the lifetime L at the applied pressure is log 10 L=alog 10The values of a and b when expressed as A + b are determined in advance, and the ratio of the pressure during the high-pressure treatment to the breaking pressure is substituted into A in the above-mentioned number 1 using the above a and b, and the time of the high-pressure treatment is substituted into t. The life consumption rate [%] in one high-pressure treatment is 0.1% or less. The invention of embodiment 8 is a separation apparatus of embodiment 7, wherein in the supply unit, the mixed gas is supplied to the separation membrane via a supply pipe, and the control unit controls the opening degree of a control valve provided in the supply pipe. 【0014】 The above and other objects, features, aspects and advantages will be clarified by the following detailed description of the present invention with reference to the accompanying drawings. 【Brief Description of the Drawings】 【0015】 [Figure 1] It is a diagram showing the structure of the separation device. [Figure 2] It is a cross-sectional view of the zeolite membrane composite. [Figure 3] It is an enlarged cross-sectional view showing a part of the zeolite membrane composite. [Figure 4] It is a diagram showing the flow of operation of the separation device. 【Embodiments for Carrying out the Invention】 【0016】 FIG. 1 is a diagram showing the configuration of a separation device 2 according to an embodiment of the present invention. In FIG. 1, parallel slashes in the cross-section of some configurations are omitted. The separation device 2 is a device that separates a substance with high permeability (high-permeability substance) of a zeolite membrane 12 described later from a mixed gas containing a plurality of types of gases. The separation in the separation device 2 may be performed, for example, for the purpose of extracting a substance with high permeability from the mixed gas, or for the purpose of concentrating a substance with low permeability. 【0017】 The substances contained in the mixed gas include, for example, one or more substances selected from hydrogen (H2), helium (He), nitrogen (N2), oxygen (O2), water (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, mercaptans, esters, ethers, ketones, and aldehydes. The above-mentioned highly permeable substances are, for example, one or more substances selected from H2, N2, O2, H2O, CO2, and H2S. 【0018】 Nitrogen oxides are compounds of nitrogen and oxygen. The above-mentioned nitrogen oxides are, for example, nitrogen monoxide (NO), nitrogen dioxide (NO2), nitrous oxide (also called dinitrogen monoxide.) (N2O), dinitrogen trioxide (N2O3), dinitrogen tetroxide (N2O4), dinitrogen pentoxide (N2O5), etc., gases called NO X (NOx). 【0019】 Sulfur oxides are compounds of sulfur and oxygen. The above-mentioned sulfur oxides are, for example, sulfur dioxide (SO2), sulfur trioxide (SO3), etc., gases called SO X (SOx). 【0020】 Sulfur fluoride is a compound of fluorine and sulfur. The above-mentioned sulfur fluoride is, for example, disulfur difluoride (F - S - S - F, S = SF2), sulfur difluoride (SF2), sulfur tetrafluoride (SF4), sulfur hexafluoride (SF6), or disulfur decafluoride (S2F 10 ) etc. 【0021】 C1-C8 hydrocarbons are hydrocarbons containing one to eight carbon atoms. C3-C8 hydrocarbons may be linear compounds, side-chain compounds, or cyclic compounds. C2-C8 hydrocarbons may be either saturated hydrocarbons (i.e., those without double or triple bonds in the molecule) or unsaturated hydrocarbons (i.e., those with double and / or triple bonds in the molecule). Examples of C1-C4 hydrocarbons include 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). 【0022】 The organic acids mentioned above are carboxylic acids or sulfonic acids, etc. Examples of carboxylic acids include formic acid (CH2O2), acetic acid (C2H4O2), oxalic acid (C2H2O4), acrylic acid (C3H4O2), or benzoic acid (C6H5COOH). Examples of sulfonic acids include ethanesulfonic acid (C2H6O3S). These organic acids may be chain compounds or cyclic compounds. 【0023】 The alcohols mentioned above include, for example, methanol (CH3OH), ethanol (C2H5OH), isopropanol (2-propanol) (CH3CH(OH)CH3), ethylene glycol (CH2(OH)CH2(OH)), or butanol (C4H9OH). 【0024】 Mercaptans are organic compounds that have a hydrogenated sulfur (SH) group at their terminus, and are also known as thiols or thioalcohols. Examples of mercaptans include methyl mercaptan (CH3SH), ethyl mercaptan (C2H5SH), or 1-propanethol (C3H7SH). 【0025】 The esters mentioned above include, for example, formic acid esters or acetate esters. 【0026】 The ethers mentioned above include, for example, dimethyl ether ((CH3)2O), methyl ethyl ether (C2H5OCH3), or diethyl ether ((C2H5)2O). 【0027】 The ketones mentioned above include, for example, acetone ((CH3)2CO), methyl ethyl ketone (C2H5COCH3), or diethyl ketone ((C2H5)2CO). 【0028】 The aldehydes mentioned above include, for example, acetaldehyde (CH3CHO), propionaldehyde (C2H5CHO), or butanal (butyraldehyde) (C3H7CHO). 【0029】 The separation apparatus 2 in Figure 1 comprises a separation membrane module 21, a supply pipe 26, a first recovery pipe 27, and a second recovery pipe 28. The separation membrane module 21 comprises a zeolite membrane composite 1, a housing 22, and two sealing members 23. The zeolite membrane composite 1 and the sealing members 23 are housed within the housing 22. The supply pipe 26, the first recovery pipe 27, and the second recovery pipe 28 are located outside the housing 22 and connected to the housing 22. 【0030】 Figure 2 is a cross-sectional view of the zeolite membrane composite 1. Figure 3 is an enlarged cross-sectional view showing a part of the zeolite membrane composite 1. In Figure 2, the sealing portion 13, which will be described later, is not shown. The zeolite membrane composite 1 is a separation membrane composite and comprises a porous support 11 and a zeolite membrane 12, which is a separation membrane, provided on the support 11. The zeolite membrane 12 is, at least, a zeolite film formed on the surface of the support 11, and does not include a film in which zeolite particles are dispersed in an organic membrane. The zeolite membrane 12 may also contain two or more types of zeolites with different structures and compositions. In Figure 2, the zeolite membrane 12 is drawn with a thick line. In Figure 3, the zeolite membrane 12 is marked with parallel diagonal lines. Also, in Figure 3, the thickness of the zeolite membrane 12 is drawn thicker than it actually is. 【0031】 In separation device 2, separation membrane complexes other than zeolite membrane complex 1 may be used, and instead of the zeolite membrane 12, an inorganic membrane formed of inorganic materials other than zeolite, or a membrane other than an inorganic membrane, may be formed on the support 11 as the separation membrane. Alternatively, a separation membrane in which zeolite particles are dispersed in an organic membrane may be used. In the following description, the separation membrane will be assumed to be the zeolite membrane 12. 【0032】 The support 11 is a porous member that can permeate gases and liquids. In the example shown in Figure 2, the support 11 is a monolithic support in which a plurality of through holes 111 extending in the longitudinal direction (i.e., the left-right direction in Figure 2) are provided on a single, integrally molded columnar body. In the example shown in Figure 2, the support 11 is approximately cylindrical. The cross-section perpendicular to the longitudinal direction of each through hole 111 (i.e., cell) is, for example, approximately circular. In Figure 2, the diameter of the through holes 111 is depicted as larger than it actually is, and the number of through holes 111 is depicted as fewer than it actually is. The zeolite film 12 is formed on the inner circumferential surface of the through holes 111 and covers the inner circumferential surface of the through holes 111 over substantially the entire surface. 【0033】 The length of the support 11 (i.e., the length in the left-right direction in Figure 2) is, for example, 10 cm to 200 cm. The outer diameter of the support 11 is, for example, 0.5 cm to 30 cm. The distance between the central axes of adjacent through holes 111 is, for example, 0.3 mm to 10 mm. The surface roughness (Ra) of the support 11 is, for example, 0.1 μm to 5.0 μm, preferably 0.2 μm to 2.0 μm. The shape of the support 11 may be, for example, honeycomb, flat, tubular, cylindrical, columnar, or polygonal prism. If the shape of the support 11 is tubular or cylindrical, the thickness of the support 11 is, for example, 0.1 mm to 10 mm. 【0034】 The material of the support 11 can be any material (e.g., ceramic or metal) as long as it has chemical stability during the process of forming the zeolite film 12 on its surface. In this embodiment, the support 11 is formed from a ceramic sintered body. Examples of ceramic sintered bodies selected as the material for the support 11 include alumina, silica, mullite, zirconia, titania, yttria, silicon nitride, silicon carbide, etc. In this embodiment, the support 11 includes at least one of alumina, silica, and mullite. 【0035】 The support 11 may contain an inorganic binder. At least one of titania, mullite, easily sinterable alumina, silica, glass frit, clay minerals, and easily sinterable cordierite can be used as the inorganic binder. 【0036】 The average pore size of the support 11 is, for example, 0.01 μm to 70 μm, preferably 0.05 μm to 25 μm. The average pore size of the support 11 near the surface where the zeolite film 12 is formed is 0.01 μm to 1 μm, preferably 0.05 μm to 0.5 μm. The average pore size can be measured, for example, by a mercury porosimeter, palm porometer, or nanopalm porometer. Regarding the distribution of pore size throughout 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 film 12 is formed is, for example, 20% to 60%. 【0037】 The support 11 has a multilayer structure in which multiple layers with different average pore diameters are stacked in the thickness direction. The average pore diameter and sintered grain size in the surface layer, including the surface on which the zeolite film 12 is formed, are smaller than the average pore diameter and sintered grain size in 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 those described above. The materials of the multiple layers forming the multilayer structure may be the same or different. 【0038】 The zeolite membrane 12 is a porous membrane having micropores. The zeolite membrane 12 can be used as a separation membrane to separate a specific substance from a fluid containing a mixture of multiple substances using molecular sieving action. Other substances are less permeable through the zeolite membrane 12 than the specific substance. In other words, the amount of other substances that permeate through the zeolite membrane 12 is smaller than the amount of the specific substance that permeates through it. 【0039】 The thickness of the zeolite film 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. Increasing the thickness of the zeolite film 12 improves separation performance. Thinning the zeolite film 12 increases the amount of permeation. The surface roughness (Ra) of the zeolite film 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. 【0040】 The pore size of the zeolite film 12 is, for example, 1 nm or less. Preferably, the pore size of the zeolite film 12 is 0.2 nm or more and 0.8 nm or less, more preferably 0.3 nm or more and 0.7 nm or less, and even more preferably 0.3 nm or more and 0.45 nm or less. If the pore size is greater than 1 nm, the separation performance may decrease. Also, if the pore size is smaller than 0.2 nm, the amount of transmission may decrease. The pore size of the zeolite film 12 is smaller than the average pore size of the support 11 near the surface on which the zeolite film 12 is formed. 【0041】 If the maximum number of member rings in the zeolite constituting the zeolite membrane 12 is n, the pore diameter is defined as the minor axis of the n-membered ring pore. Furthermore, if the zeolite has multiple types of n-membered ring pores with equal n, the pore diameter of the zeolite membrane 12 is defined as the minor axis of the n-membered ring pore with the largest minor axis. An n-membered ring pore is a pore in which the number of oxygen atoms in the ring structure formed by the bonding of oxygen atoms with T atoms (described later) is n. Thus, the pore diameter of the zeolite membrane is uniquely determined by the skeletal structure of the zeolite, as can be seen in the International Zeolite Society's "Database of Zeolite Structures" [online] and the Internet.<URL:http: / / www.iza-structure.org / databases / > It can be determined from the values ​​disclosed. 【0042】 The type of zeolite constituting the zeolite membrane 12 is not particularly limited, but may be, for example, AEI type, AEN type, AFN type, AFV type, AFX type, BEA type, CHA type, DDR type, ERI type, ETL type, FAU type (X type, Y type), GIS type, LEV type, LTA type, MEL type, MFI type, MOR type, PAU type, RHO type, SAT type, SOD type, etc. 【0043】 The zeolite film 12 contains, for example, silicon (Si). The zeolite film 12 may also contain, for example, two or more of Si, aluminum (Al), and phosphorus (P). In this case, the zeolite constituting the zeolite film 12 can be one in which the central atom (T atom) of the oxygen tetrahedron (TO4) constituting the zeolite is only Si, or consists of Si and Al, an AlPO-type zeolite in which the T atom is Al and P, a SAPO-type zeolite in which the T atom is Si, Al and P, a MAPSO-type zeolite in which the T atom is magnesium (Mg), Si, Al and P, or a ZnAPSO-type zeolite in which the T atom is zinc (Zn), Si, Al and P. Some of the T atoms may be substituted with other elements. 【0044】 When the zeolite film 12 contains Si atoms and Al atoms, the Si / Al ratio in the zeolite film 12 is, for example, 1 or more and 100,000 or less. The Si / Al ratio is preferably 5 or more, more preferably 20 or more, and even more preferably 100 or more, and the higher the ratio, the better. The Si / Al ratio in the zeolite film 12 can be adjusted by adjusting the mixing ratio of the Si source and Al source in the raw material solution, as described later. The zeolite film 12 may also contain alkali metals. The alkali metal is, for example, sodium (Na) or potassium (K). 【0045】 From the viewpoint of increasing CO2 permeability and improving separation performance, it is preferable that the maximum number of rings in the zeolite be 8. The zeolite membrane 12 is, for example, a DDR-type zeolite. In other words, the zeolite membrane 12 is a zeolite membrane composed of a zeolite whose structural code, as defined by the International Zeolite Society, is "DDR". In this case, the intrinsic pore size of the zeolite constituting the zeolite membrane 12 is 0.36 nm × 0.44 nm, and the pore diameter is 0.36 nm. 【0046】 The CO2 permeation rate (permeence) of the zeolite membrane 12 at temperatures from 20°C to 400°C is, for example, 100 nmol / m³. 2 The pressure is above s·Pa. Furthermore, the CO2 permeation rate / CH4 leakage rate ratio (permience ratio) of the zeolite membrane 12 at 20°C to 400°C is, for example, 100 or more. The said permience and permience ratio are for when the partial pressure difference of CO2 between the supply side and the permeation side of the zeolite membrane 12 is 1.5 MPa. 【0047】 Here, we will describe an example of the manufacturing process for zeolite membrane composite 1. In the manufacturing of zeolite membrane composite 1, first, seed crystals to be used in the manufacturing of zeolite membrane 12 are prepared. Seed crystals can be obtained, for example, from DDR-type zeolite powder produced by hydrothermal synthesis. The zeolite powder may be used as seed crystals as is, or seed crystals may be obtained by processing the powder by pulverization or other means. 【0048】 Next, the porous support 11 is immersed in a dispersion containing seed crystals to attach the seed crystals to the support 11. Alternatively, the seed crystals are attached to the support 11 by bringing the dispersion containing seed crystals into contact with the portion of the support 11 on which the zeolite film 12 is to be formed. This creates a support with attached seed crystals. The seed crystals may also be attached to the support 11 by other methods. 【0049】 The support 11 to which the seed crystal is attached is immersed in a raw material solution. The raw material solution is prepared by dissolving or dispersing, for example, a Si source and a structure-directing agent (hereinafter also called "SDA") in a solvent. For example, water or an alcohol such as ethanol can be used as the solvent for the raw material solution. The SDA contained in the raw material solution is, for example, an organic substance. For example, 1-adamantanamine can be used as the SDA. 【0050】 Then, by hydrothermal synthesis, a DDR-type zeolite is grown using the seed crystal as a nucleus, thereby forming a DDR-type zeolite film 12 on the support 11. The temperature during hydrothermal synthesis is preferably 120 to 200°C. The hydrothermal synthesis time is preferably 5 to 100 hours. 【0051】 After the hydrothermal synthesis is complete, the support 11 and the zeolite membrane 12 are washed with pure water. After washing, the support 11 and the zeolite membrane 12 are dried, for example, at 80°C. After drying the support 11 and the zeolite membrane 12, the zeolite membrane 12 is heat-treated to almost completely burn off the SDA in the zeolite membrane 12, allowing it to penetrate the micropores within the zeolite membrane 12. This yields the zeolite membrane composite 1 described above. 【0052】 In an example of the zeolite membrane composite 1 shown in Figure 1, sealing portions 13 are provided at both ends of the support 11 in the longitudinal direction. The sealing portions 13 are members that cover and seal both longitudinal end faces of the support 11 and the outer peripheral surface near those end faces. The sealing portions 13 prevent gas from flowing in and out from these end faces of the support 11. The sealing portions 13 are formed of, for example, glass, resin, or metal. The material and shape of the sealing portions 13 may be changed as appropriate. Note that both longitudinal ends of each through hole 111 are not covered by the sealing portions 13, and gas can flow in and out of the through hole 111 from these ends. 【0053】 In the separation membrane module 21, the housing 22 is, for example, a substantially cylindrical tubular member. The housing 22 may be other than cylindrical. The housing 22 is a pressure vessel and is made of, for example, stainless steel or carbon steel. The longitudinal direction of the housing 22 is substantially parallel to the longitudinal direction of the zeolite membrane composite 1. A supply port 221 is provided at one end of the housing 22 in the longitudinal direction (i.e., the left end in Figure 1), and a first discharge port 222 is provided at the other end. A second discharge port 223 is provided on the side of the housing 22. A supply pipe 26 is connected to the supply port 221. A first recovery pipe 27 is connected to the first discharge port 222. A second recovery pipe 28 is connected to the second discharge port 223. The internal space of the housing 22 is a sealed space isolated from the space surrounding the housing 22. 【0054】 In the example shown in Figure 1, the housing 22 comprises a housing body 224 and two lid portions 226. The housing body 224 is a substantially cylindrical member having openings at both ends in the longitudinal direction. The housing body 224 is provided with two flange portions 225. Each of the two flange portions 225 is a substantially annular plate-shaped portion that extends radially outward from the housing body 224 around the two openings of the housing body 224. The housing body 224 and the two flange portions 225 are a single continuous member. The two lid portions 226 are fixed to the two flange portions 225 by bolting or the like, covering the two openings of the housing body 224. As a result, the two openings of the housing body 224 are airtightly sealed. The supply port 221 is provided on the left lid portion 226 in Figure 1. The first discharge port 222 is provided on the right lid portion 226 in Figure 1. The second discharge port 223 is located approximately in the center of the longitudinal direction of the housing body 224. 【0055】 The two sealing members 23 are positioned around the entire circumference of the zeolite film composite 1, between the outer circumferential surface of the zeolite film composite 1 and the inner circumferential surface of the housing 22, near both longitudinal ends of the zeolite film composite 1. Each sealing member 23 is made of a material that is impermeable to gas. In the example in Figure 1, the sealing member 23 is annular and is, for example, an O-ring made of a flexible resin. 【0056】 Each sealing member 23 adheres tightly to the outer circumferential surface of the zeolite membrane composite 1 and the inner circumferential surface of the housing 22 over its entire circumference. In the example shown in Figure 1, the sealing member 23 adheres tightly to the outer circumferential surface of the sealing portion 13 and indirectly adheres to the outer circumferential surface of the support 11 via the sealing portion 13. The space between the sealing member 23 and the outer circumferential surface of the zeolite membrane composite 1, and the space between the sealing member 23 and the inner circumferential surface of the housing 22 are sealed, making gas passage almost impossible or impossible. In the separation membrane module 21, 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. 【0057】 The supply pipe 26 connects the mixed gas supply source 91 to the separation membrane module 21. The supply pipe 26 is provided with, for example, a control valve 261 for adjusting the pressure of the mixed gas. The control valve 261 is electrically connected to a control unit 20. The control unit 20 is, for example, an electrical circuit for control or a computer having a CPU. The control unit 20 controls the opening degree of the control valve 261. A pressure gauge may be provided in the supply pipe 26, and the control valve 261 may be controlled based on the value of the pressure gauge (e.g., feedback control). The mixed gas flowing through the supply pipe 26 is supplied to the internal space of the housing 22 via a supply port 221. The supply pipe 26 may be provided with a blower or pump for pressurizing the mixed gas toward the housing 22. The supply pipe 26 and the control valve 261 constitute a supply unit 260 that supplies the mixed gas to the zeolite membrane composite 1. 【0058】 In the first recovery pipe 27, the gas discharged from the first discharge port 222 is recovered. In the second recovery pipe 28, the gas discharged from the second discharge port 223 is recovered. The first recovery pipe 27 and the second recovery pipe 28 may be provided with storage containers for storing the recovered gas, and may also be provided with blowers or pumps for transferring the gas. 【0059】 In the separation apparatus 2, a mixed gas containing multiple types of gases with different permeability of the zeolite membrane 12 is supplied from the supply source 91 to the internal space of the housing 22 via the supply pipe 26. For example, the main components of the mixed gas are CO2 and CH4. The mixed gas may also contain gases other than CO2 and CH4. The pressure of the mixed gas supplied from the supply pipe 26 to the internal space of the housing 22 (i.e., the supply pressure) is, for example, 0.1 MPaA (absolute pressure) to 20.0 MPaA. The temperature at which the separation of the mixed gas is performed is, for example, 10°C to 250°C. 【0060】 The mixed gas supplied from the supply pipe 26 to the housing 22 is introduced into each through-hole 111 of the support 11 from the left end of the zeolite membrane composite 1 in Figure 1, as indicated by arrow 251. Highly permeable gases in the mixed gas (e.g., CO2, hereinafter referred to as "highly permeable substances") permeate the zeolite membrane 12 provided on the inner circumferential surface of each through-hole 111, and the support 11, and are led out from the outer circumferential surface of the support 11. In this way, the highly permeable substances are separated from the less permeable gases in the mixed gas (e.g., CH4, hereinafter referred to as "lowly permeable substances"). 【0061】 The gas that permeates through the zeolite membrane composite 1 and is released from the outer surface of the support 11 (hereinafter referred to as "permeated substance") is discharged to the second recovery pipe 28 via the second discharge port 223 and recovered, as shown by arrow 253. The pressure of the gas discharged to the second recovery pipe 28 via the second discharge port 223 (i.e., permeation pressure) is, for example, about 1 atmosphere (0.101 MPaA). 【0062】 Furthermore, of the mixed gas, the gas other than the gas that permeated the zeolite membrane composite 1 (hereinafter referred to as "impermeable substance") passes through each through-hole 111 of the support 11 from left to right in Figure 1. The impermeable substance is discharged to the first recovery pipe 27 via the first discharge port 222 and recovered, as indicated by arrow 252. The pressure of the gas discharged to the first recovery pipe 27 via the first discharge port 222 is, for example, approximately the same as the supply pressure. In addition to the low-permeability substance described above, the impermeable substance may also include a high-permeability substance that did not permeate the zeolite membrane 12. 【0063】 Figure 4 shows the operation flow of the separation device 2. In the operation of the separation device 2, first, the supply of the mixed gas to the zeolite membrane composite 1 is started. Here, in the separation device 2, a guideline for the opening degree of the control valve 261 for supplying the mixed gas at a constant set pressure in the normal operation described later is acquired in advance as a standard opening degree. The standard opening degree is determined experimentally or empirically. When the supply of the mixed gas is started, the control unit 20 quickly opens the control valve 261 from the closed state to an opening degree greater than the standard opening degree (for example, within 10 seconds). As a result, the mixed gas flows vigorously from the supply source 91 into the housing 22 via the supply pipe 26. As a result, the pressure of the mixed gas acting on the zeolite membrane 12 temporarily becomes higher than the set pressure (for example, for a few seconds). That is, high-pressure processing is performed to supply the mixed gas to the zeolite membrane 12 at a pressure higher than the set pressure (step S11). Furthermore, if the pressure of the mixed gas fluctuates to some extent around the set pressure during normal operation, it is preferable that the pressure during high-pressure processing be higher than the maximum value of that fluctuation range. 【0064】 The pressure of the mixed gas during high-pressure processing can be adjusted by adjusting the opening degree of the control valve 261 at the start of mixed gas supply. For example, the larger the opening degree of the control valve 261 at the start of supply, the higher the pressure of the mixed gas during high-pressure processing. Even if the control valve 261 is quickly opened from the closed state to the standard opening degree at the start of mixed gas supply, the pressure of the mixed gas acting on the zeolite membrane 12 will temporarily be higher than the set pressure. The duration of high-pressure processing can also be adjusted by adjusting the opening degree of the control valve 261. For example, the longer the control valve 261 is opened beyond the standard opening degree, the longer the high-pressure processing time. The above operations have the same effect as high-pressure processing even when the set pressure is changed for a short period of time. As described above, by intentionally causing an overshoot during high-pressure processing at the start of mixed gas supply to the zeolite membrane 12, unwanted substances (such as moisture and hydrocarbon components from the air) attached to the zeolite membrane 12 are removed. 【0065】 When the control valve 261 is controlled based on the pressure gauge value, an overshoot of the mixed gas pressure may be generated at the start of mixed gas supply by taking advantage of the time required for the pressure to stabilize due to the response delay of the control valve 261. The overshoot of the mixed gas pressure may also be caused by a response delay of equipment other than the control valve 261. In addition, high-pressure processing may be performed by slowly opening the control valve 261 from the closed state to an opening greater than the standard opening at the start of mixed gas supply. In this case as well, during the period when the opening is greater than the standard opening, the pressure of the mixed gas acting on the zeolite film 12 will be higher than the set pressure, and unwanted substances attached to the zeolite film 12 will be removed. Furthermore, the control valve 261 may be controlled based on the pressure gauge value so that the pressure of the mixed gas is higher than the set pressure. High-pressure processing may be performed not only simultaneously with the start of mixed gas supply, but also in conjunction with the start of mixed gas supply. 【0066】 The pressure of the mixed gas during high-pressure processing is, for example, 10 times or less the set pressure. This more reliably prevents damage to the separation device 2 due to excessive pressure. The pressure of the mixed gas during high-pressure processing is, for example, 1.1 times or more the set pressure, preferably 1.2 times or more, more preferably 1.3 times or more, and even more preferably 1.5 times or more. The high-pressure processing time, i.e., the time during which the pressure of the mixed gas is maintained above the set pressure, is, for example, 0.1 seconds to 10,000 seconds. To more reliably remove unwanted substances attached to the zeolite film 12, the high-pressure processing time is preferably 1 second or more, more preferably 3 seconds or more, and even more preferably 5 seconds or more. To shorten the time required for removal of unwanted substances, the high-pressure processing time is preferably 300 seconds or less, more preferably 100 seconds or less, and even more preferably 30 seconds or less. In addition, separation of highly permeable substances is performed in parallel during high-pressure processing. 【0067】 In high-pressure processing, when the ratio of the pressure during high-pressure processing (pressure during high-pressure processing / fracture pressure) to the fracture pressure (the pressure at which the zeolite film 12 is destroyed in a short time, as described later) is substituted into A in Equation 2, and the time of high-pressure processing is substituted into t to obtain the lifetime consumption rate [%] for one high-pressure processing cycle, it is preferable that the lifetime consumption rate is 0.1% or less. It is more preferable that the lifetime consumption rate is 0.01% or less, and even more preferable that it is 0.001% or less. This allows for appropriate suppression of lifetime consumption, as will be described later. There is no particular lower limit to the lifetime consumption rate (it is greater than 0%). The derivation of Equation 2 will be described later. 【0068】 【number】 【0069】 If the pressure is not constant during high-pressure processing (for example, if the overshoot described above occurs), it is preferable to substitute the value obtained by dividing the maximum pressure during high-pressure processing by the burst pressure into A in Equation 2. In this case, the actual life consumption rate will be smaller than the life consumption rate obtained by Equation 2. For example, the pressure during high-pressure processing (the maximum pressure mentioned above) is measured by a pressure gauge installed in the supply pipe 26. When high-pressure processing is performed under certain conditions, if the pressure during high-pressure processing under those conditions is known, the life consumption rate may be determined using the known pressure without measuring the pressure. The same applies to the time of high-pressure processing. 【0070】 Once the high-pressure treatment is complete, the separation device 2 is operated normally (step S12). During normal operation, the pressure of the mixed gas acting on the zeolite membrane 12 is set to a constant pressure, and in this state, highly permeable substances in the mixed gas are separated from low-permeable substances. The set pressure is preferably 0.1 MPaG (gauge pressure) to 8 MPaG. Because unwanted substances attached to the zeolite membrane 12 are removed during the high-pressure treatment, the amount of highly permeable substances that permeate through the zeolite membrane composite 1 increases. 【0071】 As previously described, the standard opening is a guideline for the opening of the control valve 261 to supply the mixed gas at the set pressure, and in normal operation, the control valve 261 is adjusted to approximately the standard opening. If the opening of the control valve 261 at the start of mixed gas supply is set to the standard opening, the mixed gas will reach the set pressure once the flow of the mixed gas in the supply pipe 26 reaches a steady state after the start of mixed gas supply. The control valve 261 may also be controlled based on the value of the pressure gauge so that the pressure of the mixed gas reaches the set pressure. 【0072】 When normal operation is stopped due to maintenance of the separation device 2, it is preferable that the same process as in step S11 above be performed when normal operation is resumed after the maintenance is completed. That is, when the supply of the mixed gas to the zeolite membrane 12 is started when normal operation is resumed, high-pressure treatment is performed in the same manner as above. Alternatively, high-pressure treatment may be performed during normal operation by temporarily increasing the opening of the control valve 261 to a larger opening than the standard opening, thereby removing unwanted substances attached to the zeolite membrane 12. In this case as well, it is preferable that the pressure and time during high-pressure treatment be determined so that the life consumption rate [%] for a single high-pressure treatment is 0.1% or less. 【0073】 Here, the lifetime consumption rate of the zeolite membrane 12 will be explained. Before operating the separation device 2, experiments are conducted to determine the lifetime consumption rate in high-pressure processing (equation 2 above). Specifically, multiple zeolite membrane composites are prepared, manufactured under the same conditions as the zeolite membrane composite 1 installed in the separation device 2. Each zeolite membrane composite is placed in a furnace, and the zeolite membrane is regenerated by heating. In the regeneration of the zeolite membrane, for example, it is heated from room temperature to 380°C over 15.2 hours in an atmospheric environment (heating rate 25°C / hr), held at 380°C for 8 hours, and then cooled back down to room temperature over 15.2 hours (cooling rate 25°C / hr). This removes unwanted substances (moisture, hydrocarbon components in the air, etc.) attached to the zeolite membrane 12. 【0074】 The zeolite membrane composite is removed from the furnace and placed in the housing 22 shown in Figure 1. Gas separation measurements are then performed using this zeolite membrane composite. For the gas separation measurements, a mixed gas of CO2 and CH4 in a 50:50 (volume ratio) ratio is used. The measurement temperature is set to 25°C, the supply pressure to 0.3 MPaG, and the permeate pressure to 0 MPaG. The amount of CO2 and CH4 permeate is obtained from the permeate material discharged from the second discharge port 223, and the ratio of the amount of CO2 permeate to the amount of CH4 permeate (CO2 permeate / CH4 permeate) is determined as the separation ratio. This separation ratio is the separation ratio before the application of pressure, as described later, and is hereinafter referred to as the "initial separation ratio". 【0075】 Next, pressure is applied to the zeolite membrane. During the pressure application, water is supplied to the housing 22 from the supply port 221 at a constant pressure, and pressure is applied to the zeolite membrane of the zeolite membrane composite. After the pressure is applied to the zeolite membrane for a predetermined time, the zeolite membrane composite is removed from the housing 22. The zeolite membrane composite is placed in a furnace, and the zeolite membrane is regenerated by heating in the same manner as described above. After the regeneration of the zeolite membrane, gas separation measurements are performed, and the separation ratio after pressure application is determined. 【0076】 For each zeolite membrane composite, the application of the above pressure, the regeneration of the zeolite membrane by heating, and the gas separation measurement are repeated. At this time, the applied pressure for one zeolite membrane composite is constant, and the application time of the applied pressure is appropriately changed. Also, for multiple zeolite membrane composites, the applied pressures are different. When the separation ratio after the application of pressure becomes 10% or less of the initial separation ratio, the zeolite membrane of the zeolite membrane composite is considered to have reached its lifespan, and the total sum of the application times of the applied pressure up to that point is defined as the lifespan time of the zeolite membrane at that applied pressure. In this experiment, very large applied pressures are also used, and the applied pressure at which the lifespan time becomes 1 second or less is obtained as the breaking pressure (also called the internal pressure breaking strength). In the case where the lifespan time becomes 1 second or less at multiple applied pressures, for example, the minimum applied pressure is taken as the breaking pressure. Thus, for the zeolite membrane 12, the lifespan time and the breaking pressure at each applied pressure are obtained. 【0077】 Subsequently, with the ratio of the applied pressure to the breaking pressure (applied pressure / breaking pressure) for each applied pressure being A, and the lifespan time at that applied pressure being L [seconds], the relationship between the ratio A and the lifespan time L is expressed as log 10 L = alog 10 A + b, and the values of a and b are determined by the least squares method. In other words, in a double logarithmic graph where the vertical axis represents logL and the horizontal axis represents logA, the slope a and the intercept b of the approximate straight line showing the relationship between logL and logA are determined. a and b are characteristic values derived from the type and structure of the zeolite membrane, etc. 【0078】 The above formula can be transformed into L = A a × 10 b Also, the lifespan consumption rate [%] in one high-pressure treatment is the ratio of the time t of one high-pressure treatment to the lifespan L, and is obtained by (t / L) × 100. Here, L = A a × 10 bBy substituting the values, the life consumption rate [%] in one high-pressure treatment is expressed as equation 2 above. As previously stated, A in equation 2 is the ratio of the pressure during high-pressure treatment to the burst pressure. If high-pressure treatment is performed N times (N is an integer of 1 or more) with the same pressure and time during high-pressure treatment, the life consumption rate [%] in N high-pressure treatments is expressed by equation 3. 【0079】 【number】 【0080】 Next, we will explain Experimental Examples 1-8 of the high-pressure treatment with reference to Table 1. In Experimental Examples 1-8, the pressure and time of high-pressure treatment were changed. In Table 1, "Pressure Ratio" is the ratio of the pressure during high-pressure treatment to the set pressure during normal operation, and "Pressure Time" is the time of high-pressure treatment. Note that the set pressure differs depending on the state of the supply source, etc., so the set pressure was different between Experimental Examples 1-5,7 and Experimental Examples 6,8. "A" is the ratio of the pressure during high-pressure treatment to the burst pressure, and "Number of Times" is the number of times high-pressure treatment is performed. "Life Consumption Rate" is the life consumption rate including the number of times, and is calculated using Equation 3. 【0081】 [Table 1] 【0082】 In Experimental Examples 1-8, the amount of CO2 permeate after high-pressure treatment was also measured. For the measurement of permeate, a mixed gas of CO2 and CH4 in a 50:50 (volume ratio) was used, with a measurement temperature of 25°C, a supply pressure of 0.3 MPaG, and a permeation pressure of 0 MPaG. In Table 1, "Relative CO2 Permeate" is the ratio of the amount of CO2 permeate after high-pressure treatment to the amount of CO2 permeate in Reference Example 1 without high-pressure treatment. "Relative Separation Ratio" is the ratio of the separation ratio after high-pressure treatment to the separation ratio in Reference Example 1. 【0083】 In Experimental Examples 1-8, where high-pressure treatment was performed, the relative CO2 permeation rate was greater than 100% in all cases, indicating improved permeation performance of the zeolite membrane. In Experimental Examples 1-4, where the set pressure and pressurization time were the same, the relative CO2 permeation rate increased with increasing pressure ratio. Also, the relative separation ratio was 100 or higher in all of Experimental Examples 1-4. In Experimental Example 5, the pressurization time was extended 100 times compared to Experimental Example 3, but the lifetime consumption rate was less than 0.1%, and the relative separation ratio was also 100 or higher. In Experimental Example 6, the pressurization ratio and pressurization time were the same as in Experimental Example 1, but because ratio A was larger, the lifetime consumption rate was significantly greater than 0.1%. In Experimental Example 7, the pressurization ratio and ratio A were the same as in Experimental Example 1, but the pressurization time was extended 1,000,000 times, resulting in a lifetime consumption rate significantly greater than 0.1%. In Experimental Examples 6 and 7, the relative separation ratio was less than 100. In Experimental Example 8, extending the pressurization time in Experimental Example 6 by 100 times resulted in a lifespan consumption rate exceeding 100% and a significant decrease in the relative separation ratio. 【0084】 As explained above, the operation method of the separation device 2 involves supplying a mixed gas containing multiple types of gases to the separation membrane (zeolite membrane 12 in the above example) at a constant set pressure, thereby performing a normal operation in which substances in the mixed gas with high permeability to the separation membrane are separated from other substances (step S 12 ) and a process (step S) in which the mixed gas is supplied to the separation membrane at a pressure higher than the set pressure when the supply of the mixed gas to the separation membrane is started before normal operation, or during normal operation. 11 ) and are equipped with. 【0085】 In the conventional operation method of the separation device, the control valve 261 is slowly opened from the closed state to the standard opening when the mixed gas supply begins, so the pressure of the mixed gas gradually increases to the set pressure. In other words, the mixed gas is never supplied to the separation membrane at a pressure higher than the set pressure. Also, in normal operation, the pressure of the mixed gas is maintained at a constant set pressure. In contrast, in the above operation method of the separation device 2, the mixed gas is intentionally made to a pressure higher than the set pressure when the supply of the mixed gas to the separation membrane begins, or during normal operation. This makes it possible to remove unwanted substances attached to the separation membrane using the mixed gas that is to be processed, and it is possible to easily improve the permeability performance of the separation membrane (improve the permeation rate of highly permeable substances) without using a heater or a gas other than the mixed gas. Furthermore, by improving the permeability performance of the separation membrane, it becomes possible to reduce the number of separation membrane composites installed in the separation device 2. 【0086】 Preferably, for a separation membrane, the relationship between the ratio A of the applied pressure to the breakdown pressure and the lifetime L at the applied pressure is defined as log 10 L=alog 10 The values ​​of a and b in the expression A+b can be determined in advance. Then, by substituting the ratio of the pressure during high-pressure processing to the burst pressure for A in the above equation 2 using a and b, and substituting the time of high-pressure processing for t, the lifetime consumption rate [%] in one high-pressure processing cycle is obtained to be 0.1% or less. This makes it possible to appropriately suppress the lifetime consumption (damage) of the separation membrane during high-pressure processing, and even when high-pressure processing is repeated, it is possible to maintain a high relative separation ratio and extend the lifespan of the separation membrane. As a result, the replacement cycle of the separation membrane complex can be extended (i.e., the number of replacements of the separation membrane complex in a given period can be reduced). 【0087】 Preferably, in the separation device 2, a control valve 261 is provided between the mixed gas supply source 91 and the separation membrane. A standard opening degree of the control valve 261 for supplying the mixed gas to the separation membrane at a set pressure is acquired in advance, and when the supply of the mixed gas to the separation membrane begins, the opening degree of the control valve 261 is adjusted to an opening degree greater than or equal to the standard opening degree. This makes it possible to easily perform high-pressure processing without installing a booster or the like in the supply pipe 26, and as a result, space can be saved compared to when a booster or the like is installed. Depending on the pressure of the mixed gas supplied from the supply source 91, a booster or the like may be installed in the supply pipe 26. 【0088】 Preferably, the set pressure is 0.1 MPaG to 8 MPaG, and the pressure during high-pressure processing is 10 times or less the set pressure. This prevents damage to the separation device 2 due to the use of excessively high pressure during high-pressure processing. 【0089】 Preferably, the high-pressure treatment time is 0.1 seconds to 10,000 seconds. This allows for the removal of unwanted substances attached to the separation membrane in a shorter time compared to the case where the separation membrane composite is removed from the housing 22 and heated in the furnace, as in the regeneration of the zeolite membrane by heating described above. 【0090】 Preferably, the separation membrane is a zeolite membrane 12. This allows for proper separation of the mixed gas. Furthermore, if the maximum number of member rings of the zeolite constituting the zeolite membrane 12 is 8, selective permeation of substances with relatively small molecular diameters can be appropriately achieved. 【0091】 The separation device 2 comprises a separation membrane (zeolite membrane 12 in the above example), a supply unit 260 that separates the mixed gas by supplying the mixed gas to the separation membrane, and a control unit 20 that controls the supply unit 260 to perform normal operation by supplying the mixed gas to the separation membrane at a constant set pressure, and also performs high-pressure processing by supplying the mixed gas to the separation membrane at a pressure higher than the set pressure when supplying the mixed gas to the separation membrane before normal operation or during normal operation. This makes it possible to easily improve the permeability performance of the separation membrane by removing unwanted substances adhering to it. 【0092】 The operating method of the separation device 2 described above, and the separation device 2 itself, can be modified in various ways. 【0093】 If the number of high-pressure treatments performed on the zeolite membrane 12 is infrequent, the life consumption rate [%] in a single high-pressure treatment may be greater than 0.1%. Depending on the structure of the separation device 2, the set pressure may be greater than 8 MPaG, and the pressure during high-pressure treatment may be greater than 10 times the set pressure. Also, the high-pressure treatment time may be longer than 10,000 seconds. 【0094】 In addition to adjusting the opening degree of the control valve 261, supplying a mixed gas at a pressure higher than the set pressure to the zeolite membrane 12 may also be achieved by using, for example, a blower or pressurizer installed in the supply pipe 26. 【0095】 In the zeolite membrane composite 1, a zeolite membrane 12 may be formed on the outer surface of the support 11. As previously described, the support 11 may be of a type other than monolith. 【0096】 In addition to the support 11 and the zeolite film 12, the zeolite film composite 1 may further include a functional film or protective film laminated on the zeolite film 12. Such a functional film or protective film may be an inorganic film such as a zeolite film, silica film, or carbon film, or an organic film such as a polyimide film or silicone film. Furthermore, the functional film or protective film laminated on the zeolite film 12 may contain a substance that readily adsorbs specific molecules such as CO2. 【0097】 The type of zeolite constituting the zeolite membrane 12 may be changed as appropriate, and the maximum number of rings of the zeolite may be other than 8. As previously described, the separation membrane may be other than the zeolite membrane 12. 【0098】 In separation apparatus 2 using a separation membrane, substances other than those exemplified in the above description may be separated from the mixed gas. 【0099】 The configurations in the above embodiments and each modified example may be combined as appropriate, as long as they do not contradict each other. 【0100】 Although the invention has been described in detail, the above description is illustrative and not limiting. Therefore, it can be said that numerous modifications and embodiments are possible as long as they do not deviate from the scope of the present invention. [Industrial applicability] 【0101】 The operating method and separation apparatus according to the present invention can be used in various fields that utilize separation membranes. [Explanation of symbols] 【0102】 2 Separation device 12 Zeolite membrane 20 Control Unit 260 Supply section S11, S12 Step

Claims

[Claim 1] A method for operating a separation apparatus using a separation membrane, A normal operation is performed in which a mixed gas containing multiple types of gases is supplied to a separation membrane at a constant set pressure, thereby separating substances in the mixed gas that have high permeability to the separation membrane from other substances. A step of performing a high-pressure treatment in which the mixed gas is supplied to the separation membrane at a pressure higher than the set pressure when the supply of the mixed gas to the separation membrane begins before the normal operation, or during the normal operation, Equipped with, Regarding the separation membrane, the relationship between the ratio A of the applied pressure to the breakdown pressure and the lifetime L at the applied pressure is log １０ L = alog １０ The values ​​of a and b when expressed as A + b have been determined in advance. A method for operating a separation apparatus in which the life consumption rate [%] in one high-pressure treatment cycle is 0.1% or less, obtained by substituting the ratio of the pressure during the high-pressure treatment to the burst pressure for A in the following equation using a and b above, and substituting the time of the high-pressure treatment for t. [Math 1] [Claim 2] A method for operating the separation apparatus according to Claim 1, The mixed gas is supplied to the separation membrane via the supply pipe. A method for operating a separation apparatus in which high-pressure processing is performed by adjusting the opening degree of a control valve provided in the supply pipe. [Claim 3] A method for operating the separation apparatus according to claim 1 or 2, The set pressure is 0.1 MPaG to 8 MPaG. A method for operating a separation apparatus in which the pressure during the high-pressure processing is 10 times or less the set pressure. [Claim 4] A method for operating the separation apparatus according to claim 1 or 2, A method for operating a separation apparatus in which the high-pressure processing time is 0.1 seconds to 10,000 seconds. [Claim 5] A method for operating the separation apparatus according to claim 1 or 2, A method for operating a separation apparatus in which the separation membrane is a zeolite membrane. [Claim 6] A method for operating the separation apparatus according to claim 5, A method for operating a separation apparatus in which the maximum number of rings of zeolites constituting the zeolite membrane is 8. [Claim 7] A separation device, Separation membrane and A supply unit that supplies a mixed gas containing multiple types of gases to the separation membrane, thereby separating substances in the mixed gas that have high permeability to the separation membrane from other substances, A control unit controls the supply unit to perform normal operation, supplying the mixed gas to the separation membrane at a constant set pressure, and performs high-pressure processing to supply the mixed gas to the separation membrane at a pressure higher than the set pressure when the supply of the mixed gas to the separation membrane begins before the normal operation, or during the normal operation. Equipped with, Regarding the separation membrane, the relationship between the ratio A of the applied pressure to the breakdown pressure and the lifetime L at the applied pressure is log １０ L = alog １０ The values ​​of a and b when expressed as A + b have been determined in advance. A separation device in which the life consumption rate [%] in one high-pressure treatment cycle is 0.1% or less, obtained by substituting the ratio of the pressure during the high-pressure treatment to the burst pressure for A in the following equation using a and b above, and substituting the time of the high-pressure treatment for t. [Math 2] [Claim 8] The separation device according to claim 7, In the supply unit, the mixed gas is supplied to the separation membrane via the supply pipe. A separation device in which the control unit controls the opening degree of a control valve provided in the supply pipe.

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