Method for operating separation device and separation device

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

Separation device operating method and separation device

[0001] The present invention relates to a method for operating a separation apparatus and a separation apparatus. [Reference to Related Applications] This application claims the benefit of priority from Japanese Patent Application JP2022-92971, filed on June 8, 2022, the entire disclosure of which is incorporated herein by reference.

[0002] Conventionally, methods for improving the permeability of separation membranes have been investigated. Japanese Patent Application Laid-Open No. 2012-236123 (Document 1) discloses a method for removing water of crystallization from an FAU-type zeolite membrane by heating and drying it at a temperature of 100 to 600°C, and then maintaining the membrane in a dry state to obtain high carbon dioxide permeability. International Publication No. 2018 / 180210 (Document 2) also discloses a method for regenerating a zeolite membrane. In this method, a zeolite membrane contacted with a hydrocarbon mixture is pressurized while exposed to an inert gas atmosphere, and the atmosphere is then heated. Japanese Patent Application Laid-Open No. 2018-183756 (Document 3) discloses a method for regenerating a separation membrane module, in which a raw material mixed gas is supplied to a separation membrane module and separated into a permeate gas and a non-permeate gas, and the permeate gas is supplied to a separation membrane module in which the supply of the raw material mixed gas has been stopped or to another separation membrane module, thereby removing impurities adhering to the hollow fiber membrane.

[0003] Separation membranes are usually transported between their production and actual use. Separation membranes may also be stored for long periods of time before use. During transportation or long-term storage, unwanted substances, such as moisture and hydrocarbon components in the air, may adhere to the separation membrane, blocking some of the pores in the membrane and reducing its permeability. When removing unwanted substances by heating, as in Reference 1, a heater is required. Furthermore, heating at high temperatures may shorten the life of the separation membrane. When heating or pressurizing is performed using an inert gas, as in Reference 2, a heater is required, as described above, and additional inert gas must also be prepared. When regenerating a separation membrane using permeation gas that has permeated the separation membrane, as in Reference 3, two lines (series), each containing a separation membrane, are required, resulting in an increase in the size of the equipment and in space and costs.

[0004] An object of the present invention is to easily improve the permeation performance of a separation membrane.

[0005] A first aspect of the invention is a method for operating a separation device using a separation membrane, comprising: a step of performing a normal operation 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 are highly permeable through the separation membrane from other substances; and a step of performing a high-pressure treatment in which, at the start of supplying the mixed gas to the separation membrane before the normal operation or during the normal operation, the mixed gas is supplied to the separation membrane at a pressure higher than the set pressure.

[0006] According to the present invention, unnecessary substances adhering to the separation membrane can be removed, and the permeation performance of the separation membrane can be easily improved.

[0007] A second aspect of the present invention is a method for operating a separation apparatus according to the first aspect, wherein the relationship between the ratio A of the applied pressure to the breakdown pressure of the separation membrane and the lifetime L at the applied pressure is expressed as log １０ L = log 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 is obtained by substituting the ratio of the pressure during the high-pressure treatment to the burst pressure for A and substituting the time of the high-pressure treatment for t in the following formula using a and b, and is 0.1% or less.

[0008]

[0009] A third aspect of the invention is the method for operating the separation apparatus of the first or second aspect, wherein the set pressure is 0.1 MPaG to 8 MPaG, and the pressure during the high-pressure treatment is 10 times or less the set pressure.

[0010] A fourth aspect of the present invention is the method for operating the separation apparatus according to any one of the first to third aspects, wherein the high-pressure treatment is carried out for a period of 0.1 to 10,000 seconds.

[0011] A fifth aspect of the present invention is the method for operating the separation apparatus according to any one of the first to fourth aspects, wherein the separation membrane is a zeolite membrane.

[0012] A sixth aspect of the present invention is the method for operating the separation apparatus of the fifth aspect, wherein the maximum number of rings in the zeolite constituting the zeolite membrane is eight.

[0013] A seventh aspect of the invention is 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 a substance in the mixed gas that has high permeability through the separation membrane from other substances; and a control unit that controls the supply unit to perform a normal operation in which the mixed gas is supplied to the separation membrane at a constant set pressure, and that performs a high-pressure treatment in which the mixed gas is supplied to the separation membrane at a pressure higher than the set pressure when supply of the mixed gas to the separation membrane starts before the normal operation or during the normal operation.

[0014] The above and other objects, features, aspects and advantages will become more apparent from the following detailed description of the invention which proceeds with reference to the accompanying drawings.

[0015] It is a diagram showing the structure of a separation device. It is a cross-sectional view of a zeolite membrane composite. It is a cross-sectional view showing an enlarged part of the zeolite membrane composite. It is a diagram showing the operation flow of a separation device.

[0016] FIG. 1 is a diagram showing the configuration of a separation device 2 according to one embodiment of the present invention. In FIG. 1, the hatched lines in the cross sections of some components are omitted. The separation device 2 is a device that separates a substance (highly permeable substance) that has high permeability through a zeolite membrane 12 (described later) from a mixed gas containing multiple types of gases. Separation in the separation device 2 may be performed, for example, for the purpose of extracting a highly permeable substance from the mixed gas, or for the purpose of concentrating a less permeable substance.

[0017] The substances contained in the mixed gas include, for example, hydrogen (H ２ ), helium (He), nitrogen (N ２ ), oxygen (O ２ ), water (H ２ O), carbon monoxide (CO), carbon dioxide (CO ２ ), nitrogen oxides, ammonia (NH ３ ), sulfur oxides, hydrogen sulfide (H ２ S), sulfur fluoride, mercury (Hg), arsine (AsH ３), hydrogen cyanide (HCN), carbonyl sulfide (COS), C1-C8 hydrocarbons, organic acids, alcohols, mercaptans, esters, ethers, ketones, and aldehydes. ２ , N ２ , O ２ , H ２ O, CO ２ and H ２ S is one or more substances.

[0018] Nitrogen oxides are compounds of nitrogen and oxygen. Examples of the nitrogen oxides include nitric oxide (NO), nitrogen dioxide (NO ２ ), nitrous oxide (also called dinitrogen monoxide) (N ２ O), dinitrogen trioxide (N ２ O ３ ), dinitrogen tetroxide (N ２ O ４ ), dinitrogen pentoxide (N ２ O ５ ) etc. Ｘ It is a gas called NOX.

[0019] Sulfur oxides are compounds of sulfur and oxygen. Examples of the sulfur oxides include sulfur dioxide (SO ２ ), sulfur trioxide (SO ３ ) and other SOs Ｘ It is a gas called SOX.

[0020] Sulfur fluoride is a compound of fluorine and sulfur. The above-mentioned sulfur fluoride is, for example, disulfur difluoride (FS-SF, S=SF ２ ), sulfur difluoride (SF ２ ), sulfur tetrafluoride (SF ４ ), sulfur hexafluoride (SF ６ ) or disulfur decafluoride (S ２ F １０ ) etc.

[0021] C1-C8 hydrocarbons are hydrocarbons with one or more carbon atoms and eight or less. C3-C8 hydrocarbons may be straight-chain compounds, branched-chain compounds, or cyclic compounds. C2-C8 hydrocarbons may be either saturated hydrocarbons (i.e., those without double and triple bonds in the molecule) or unsaturated hydrocarbons (i.e., those with double and / or triple bonds in the molecule). C1-C4 hydrocarbons include, for example, methane (CH ４ ), ethane (C ２ H ６ ), ethylene (C ２ H ４ ), propane (C ３ H ８ ), propylene (C ３ H ６ ), normal butane (CH ３ (CH ２ ) ２ CH ３ ), isobutane (CH(CH ３ ) ３ ), 1-butene (CH ２ =CHCH ２ CH ３ ), 2-butene (CH ３ CH=CHCH ３ ) or isobutene (CH ２ =C(CH ３ ) ２ )

[0022] The organic acid is a carboxylic acid or a sulfonic acid. The carboxylic acid is, for example, formic acid (CH ２ O ２ ), acetic acid (C ２ H ４ O ２ ), oxalic acid (C ２ H ２ O ４ ), acrylic acid (C ３ H ４ O ２ ) or benzoic acid (C ６ H ５ COOH), etc. Sulfonic acids include, for example, ethanesulfonic acid (C ２ H ６ O ３S) and the like. The organic acid may be a chain compound or a cyclic compound.

[0023] The alcohols mentioned above include, for example, methanol (CH ３ OH), ethanol (C ２ H ５ OH), isopropanol (2-propanol) (CH ３ CH(OH)CH ３ ), ethylene glycol (CH ２ (OH)CH ２ (OH)) or butanol (C ４ H ９ OH) and the like.

[0024] Mercaptans are organic compounds with hydrogenated sulfur (SH) at the end, and are also called thiols or thioalcohols. Examples of the above-mentioned mercaptans include methyl mercaptan (CH ３ SH), ethyl mercaptan (C ２ H ５ SH) or 1-propanethiol (C ３ H ７ SH), etc.

[0025] The esters mentioned above are, for example, formates or acetates.

[0026] The above-mentioned ethers include, for example, dimethyl ether ((CH ３ ) ２ O), methyl ethyl ether (C ２ H ５ OCH ３ ) or diethyl ether ((C ２ H ５ ) ２ O) etc.

[0027] The above-mentioned ketones can be, for example, acetone ((CH ３ ) ２ CO), methyl ethyl ketone (C ２ H ５ COCH ３ ) or diethyl ketone ((C ２ H ５ ) ２ CO), etc.

[0028] The aldehydes mentioned above include, for example, acetaldehyde (CH ３ CHO), propionaldehyde (C ２ H ５ CHO) or butanal (butyraldehyde) (C ３ H ７ CHO) etc.

[0029] 1 includes 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 includes a zeolite membrane composite 1, a housing 22, and two seal members 23. The zeolite membrane composite 1 and the seal members 23 are housed within the housing 22. The supply pipe 26, the first recovery pipe 27, and the second recovery pipe 28 are disposed outside the housing 22 and connected to the housing 22.

[0030] FIG. 2 is a cross-sectional view of the zeolite membrane composite 1. FIG. 3 is a cross-sectional view showing an enlarged portion of the zeolite membrane composite 1. In FIG. 2, the plugging portion 13, which will be described later, is omitted. The zeolite membrane composite 1 is a separation membrane composite and includes 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 membrane of zeolite formed on the surface of the support 11, and does not include a membrane in which zeolite particles are simply dispersed in an organic film. The zeolite membrane 12 may also contain two or more types of zeolite with different structures or compositions. In FIG. 2, the zeolite membrane 12 is depicted with a thick line. In FIG. 3, the zeolite membrane 12 is depicted with parallel diagonal lines. In FIG. 3, the thickness of the zeolite membrane 12 is depicted thicker than it actually is.

[0031] In addition, in the separation device 2, a separation membrane composite other than the zeolite membrane composite 1 may be used, and instead of the zeolite membrane 12, an inorganic membrane formed of an inorganic substance other than zeolite, or a membrane other than an inorganic membrane, may be formed on the support 11 as the separation membrane. Also, 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.

[0032] The support 11 is a porous member that is permeable to gases and liquids. In the example shown in FIG. 2 , the support 11 is a monolithic support having a single, continuous columnar body formed integrally with the support 11, and a plurality of through-holes 111 extending in the longitudinal direction (i.e., the left-right direction in FIG. 2 ). In the example shown in FIG. 2 , the support 11 is substantially cylindrical. The cross section perpendicular to the longitudinal direction of each through-hole 111 (i.e., cell) is, for example, substantially circular. In FIG. 2 , the diameter of the through-hole 111 is drawn larger than in reality, and the number of through-holes 111 is drawn smaller than in reality. The zeolite membrane 12 is formed on the inner circumferential surface of the through-hole 111, covering the inner circumferential surface of the through-hole 111 over substantially the entire surface.

[0033] The length of the support 11 (i.e., the length in the left-right direction in FIG. 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, and preferably 0.2 μm to 2.0 μm. The shape of the support 11 may be, for example, a honeycomb shape, a flat plate shape, a tubular shape, a cylindrical shape, a columnar shape, or a polygonal columnar shape. When 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 various substances (e.g., ceramic or metal) as long as they are chemically stable in the process of forming the zeolite membrane 12 on the surface. In this embodiment, the support 11 is formed of a ceramic sintered body. Examples of ceramic sintered bodies selected as the material of the support 11 include alumina, silica, mullite, zirconia, titania, yttria, silicon nitride, and silicon carbide. In this embodiment, the support 11 includes at least one of alumina, silica, and mullite.

[0035] The support 11 may contain an inorganic binder, which may be at least one of titania, mullite, sinterable alumina, silica, glass frit, clay minerals, and sinterable cordierite.

[0036] 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 on which the zeolite membrane 12 is formed is 0.01 μm to 1 μm, preferably 0.05 μm to 0.5 μm. The average pore diameter can be measured, for example, by a mercury porosimeter, a perm porometer, or a nanoperm porometer. With regard to the pore diameter distribution 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 on which the zeolite membrane 12 is formed is, for example, 20% to 60%.

[0037] The support 11 has, for example, a multilayer structure in which multiple layers with different average pore sizes are stacked in the thickness direction. The average pore size and sintered grain size in the surface layer, including the surface on which the zeolite membrane 12 is formed, are smaller than the average pore size and sintered grain size in the layers other than the surface layer. The average pore size in the surface layer of the support 11 is, for example, 0.01 μm to 1 μm, and preferably 0.05 μm to 0.5 μm. When the support 11 has a multilayer structure, the materials described above can be used for each layer. 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 fine pores (micropores). The zeolite membrane 12 can be used as a separation membrane that separates a specific substance from a fluid containing a mixture of multiple substances by utilizing molecular sieving action. The zeolite membrane 12 is less permeable to other substances than to the specific substance. In other words, the amount of the other substances that permeates the zeolite membrane 12 is smaller than the amount of the specific substance that permeates the zeolite membrane 12.

[0039] 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. Increasing the thickness of the zeolite membrane 12 improves separation performance. Increasing the thickness of the zeolite membrane 12 increases the permeation amount. 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.

[0040] The pore diameter of the zeolite membrane 12 is, for example, 1 nm or less. The pore diameter of the zeolite membrane 12 is preferably 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 diameter is larger than 1 nm, the separation performance may decrease. On the other hand, if the pore diameter is smaller than 0.2 nm, the permeation amount may decrease. The pore diameter of the zeolite membrane 12 is smaller than the average pore diameter of the support 11 near the surface on which the zeolite membrane 12 is formed.

[0041] When the maximum number of rings in the zeolite constituting the zeolite membrane 12 is n, the minor axis of the n-ring pore is defined as the pore diameter. Furthermore, when the zeolite has multiple types of n-ring pores with the same n, the minor axis of the n-ring pore with the largest minor axis is defined as the pore diameter of the zeolite membrane 12. An n-ring pore is a pore in which the number of oxygen atoms in the ring structure formed by bonding with a T atom (described below) is n. Thus, the pore diameter of a zeolite membrane is uniquely determined by the skeletal structure of the zeolite, and can be determined from the values ​​disclosed in the International Zeolite Association's "Database of Zeolite Structures" [online] on the Internet (URL: http: / / www.iza-structure.org / databases / ).

[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, or other zeolite.

[0043] The zeolite membrane 12 contains, for example, silicon (Si). The zeolite membrane 12 may contain, for example, any two or more of Si, aluminum (Al), and phosphorus (P). In this case, the zeolite constituting the zeolite membrane 12 may be an oxygen tetrahedron (TO) constituting the zeolite. ４ Zeolites in which the atom (T atom) located at the center of the zeolite (T atom) is composed of only Si or Si and Al, AlPO zeolites in which the T atoms are composed of Al and P, SAPO zeolites in which the T atoms are composed of Si, Al, and P, MAPSO zeolites in which the T atoms are composed of magnesium (Mg), Si, Al, and P, and ZnAPSO zeolites in which the T atoms are composed of zinc (Zn), Si, Al, and P can be used. Some of the T atoms may be substituted with other elements.

[0044] 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 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 Si / Al ratio, the better. The Si / Al ratio in the zeolite membrane 12 can be adjusted by adjusting the blending ratio of the Si source and the Al source in the raw material solution, which will be described later. The zeolite membrane 12 may contain an alkali metal. The alkali metal is, for example, sodium (Na) or potassium (K).

[0045] CO ２From the viewpoint of increasing the permeation amount and improving separation performance, the maximum number of rings in the zeolite is preferably 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 structure code is "DDR" as defined by the International Zeolite Society. 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] CO of zeolite membrane 12 at 20°C to 400°C ２ The permeance is, for example, 100 nmol / m ２ .s.Pa or more. In addition, the CO ２ Transmission amount / CH ４ The leakage ratio (permeance ratio) is, for example, 100 or more. The permeance and the permeance ratio are determined by the ratio of the CO 2 ２ The partial pressure difference is 1.5 MPa.

[0047] Here, an example of a flow of manufacturing the zeolite membrane composite 1 will be described. In the manufacturing of the zeolite membrane composite 1, first, seed crystals to be used in manufacturing the zeolite membrane 12 are prepared. For example, a powder of DDR-type zeolite is produced by hydrothermal synthesis, and the seed crystals are obtained from the zeolite powder. The zeolite powder may be used as it is as the seed crystals, or the seed crystals may be obtained by processing the powder by pulverization or the like.

[0048] Next, the porous support 11 is immersed in the dispersion liquid in which the seed crystals are dispersed, and the seed crystals are attached to the support 11. Alternatively, the dispersion liquid in which the seed crystals are dispersed 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 way, a seed crystal-attached support is produced. The seed crystals may also be attached to the support 11 by other techniques.

[0049] The support 11 with the seed crystal attached thereto 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 referred to as "SDA") in a solvent. The solvent for the raw material solution is, for example, water or an alcohol such as ethanol. 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, DDR-type zeolite is grown by hydrothermal synthesis using the seed crystals as nuclei, 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 5 to 100 hours.

[0051] After the hydrothermal synthesis is completed, the support 11 and the zeolite membrane 12 are washed with pure water. The washed support 11 and the zeolite membrane 12 are dried, for example, at 80°C. After the support 11 and the zeolite membrane 12 are dried, the zeolite membrane 12 is subjected to a heat treatment, whereby the SDA in the zeolite membrane 12 is almost completely burned off and penetrated into the micropores in the zeolite membrane 12. This gives the above-mentioned zeolite membrane composite 1.

[0052] In an example of the zeolite membrane composite 1 shown in FIG. 1 , plugs 13 are provided at both longitudinal ends of the support 11. The plugs 13 are members that cover and seal both longitudinal end faces of the support 11 and the outer peripheral surfaces near these end faces. The plugs 13 prevent gas from flowing in or out from these end faces of the support 11. The plugs 13 are formed of, for example, glass, resin, or metal. The material and shape of the plugs 13 may be changed as appropriate. Note that both longitudinal ends of each through-hole 111 are not covered by the plugs 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 have a shape other than a cylindrical shape. The housing 22 is a pressure-resistant 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 longitudinal end of the housing 22 (i.e., the left end in FIG. 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 an enclosed space isolated from the space around the housing 22.

[0054] In the example shown in FIG. 1 , the housing 22 includes a housing main body 224 and two lid portions 226. The housing main body 224 is a substantially cylindrical member with openings at both longitudinal ends. Two flange portions 225 are provided on the housing main body 224. Each of the two flange portions 225 is a substantially annular plate-shaped portion that extends radially outward from the housing main body 224 around the two openings of the housing main body 224. The housing main body 224 and the two flange portions 225 are a continuous member. The two lid portions 226 are fixed to the two flange portions 225 by bolting or the like while covering the two openings of the housing main body 224. This hermetically seals the two openings of the housing main body 224. The supply port 221 is provided on the lid portion 226 on the left side in FIG. 1 . The first discharge port 222 is provided on the lid portion 226 on the right side in FIG. 1 . The second discharge port 223 is provided at approximately the center of the housing body 224 in the longitudinal direction.

[0055] The two seal members 23 are disposed around the entire circumference between the outer peripheral surface of the zeolite membrane composite 1 and the inner peripheral surface of the housing 22 near both longitudinal ends of the zeolite membrane composite 1. Each seal member 23 is made of a gas-impermeable material. In the example shown in Fig. 1, the seal member 23 is annular and is, for example, an O-ring made of flexible resin.

[0056] Each seal member 23 is in close contact with the outer peripheral surface of the zeolite membrane composite 1 and the inner peripheral surface of the housing 22 over the entire periphery. In the example shown in Fig. 1 , the seal member 23 is in close contact with the outer peripheral surface of the sealing portion 13 and indirectly with the outer peripheral surface of the support 11 via the sealing portion 13. A seal is formed between the seal member 23 and the outer peripheral surface of the zeolite membrane composite 1, and between the seal member 23 and the inner peripheral surface of the housing 22, so that gas hardly or completely passes through. In the separation membrane module 21, the seal members 23 ensure airtightness between the second discharge port 223 and the supply port 221 and between the second discharge port 223 and the supply port 221 and the first discharge port 222.

[0057] The supply pipe 26 connects the mixed gas supply source 91 and the separation membrane module 21. The supply pipe 26 is provided with, for example, a regulating valve 261 that regulates the pressure of the mixed gas. The control unit 20 is electrically connected to the regulating valve 261. The control unit 20 is, for example, an electric control circuit or a computer having a CPU or the like. The control unit 20 controls the opening degree of the regulating valve 261. A pressure gauge may be provided in the supply pipe 26, and the regulating valve 261 may be controlled (e.g., feedback controlled) based on the value of the pressure gauge. The mixed gas flowing through the supply pipe 26 is supplied to the internal space of the housing 22 via the supply port 221. The supply pipe 26 may be provided with a blower, a pump, or the like that pressure-feeds the mixed gas toward the housing 22. The supply pipe 26 and the regulating valve 261 form a supply unit 260 that supplies the mixed gas to the zeolite membrane composite 1.

[0058] The first recovery pipe 27 recovers the gas discharged from the first discharge port 222. The second recovery pipe 28 recovers the gas discharged from the second discharge port 223. The first recovery pipe 27 and the second recovery pipe 28 may be provided with a storage container for storing the recovered gas, and may also be provided with a blower, pump, or the like for transporting the gas.

[0059] In the separation device 2, a mixed gas containing a plurality of types of gases having different permeabilities through the zeolite membrane 12 is supplied from a supply source 91 to the internal space of the housing 22 via a supply pipe 26. For example, the main components of the mixed gas are CO ２ and C.H. ４ The mixed gas contains CO ２ and C.H. ４ 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 mixed gas is separated 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 of the through-holes 111 of the support 11 from the left end of the zeolite membrane composite 1 in FIG. 1 as indicated by an arrow 251. A gas having a high permeability in the mixed gas (e.g., CO ２ The highly permeable substance (hereinafter referred to as "highly permeable substance") passes through the zeolite membrane 12 provided on the inner circumferential surface of each through-hole 111 and the support 11, and is discharged from the outer circumferential surface of the support 11. As a result, the highly permeable substance is able to disperse gases with low permeability (e.g., CH ４ (hereinafter referred to as "low permeability material").

[0061] The gas (hereinafter referred to as "permeate") that has permeated through the zeolite membrane composite 1 and is discharged from the outer peripheral surface of the support 11 is discharged to the second recovery pipe 28 via the second discharge port 223 and recovered, as indicated by arrow 253. The pressure of the gas discharged to the second recovery pipe 28 via the second discharge port 223 (i.e., the permeation pressure) is, for example, about 1 atmosphere (0.101 MPaA).

[0062] Furthermore, gases other than those that have permeated the zeolite membrane composite 1 (hereinafter referred to as "impermeable substances") of the mixed gas pass through the through-holes 111 of the support 11 from left to right in FIG. 1 . The impermeable substances are discharged to the first recovery pipe 27 via the first discharge port 222 as indicated by arrow 252 and are recovered. 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-permeable substances described above, the impermeable substances may also include highly permeable substances that have not permeated the zeolite membrane 12.

[0063] FIG. 4 illustrates the operation flow of the separation device 2. In operation of the separation device 2, first, the supply of the mixed gas to the zeolite membrane composite 1 is initiated. Here, in the separation device 2, a standard opening is previously acquired as a guideline for the opening of the regulating valve 261 for supplying the mixed gas at a constant set pressure during normal operation (described later). The standard opening is determined experimentally or empirically. When the supply of the mixed gas begins, the control unit 20 quickly (e.g., within 10 seconds) opens the regulating valve 261 from a closed state to an opening equal to or greater than the standard opening. This causes the mixed gas from the supply source 91 to forcefully flow into the housing 22 through the supply pipe 26. As a result, the pressure of the mixed gas acting on the zeolite membrane 12 temporarily (e.g., for several seconds) becomes higher than the set pressure. That is, a high-pressure treatment is performed (step S11) in which the mixed gas is supplied to the zeolite membrane 12 at a pressure higher than the set pressure. In addition, when the pressure of the mixed gas fluctuates to some extent around the set pressure during normal operation, the pressure during high-pressure treatment is preferably higher than the maximum value of the fluctuation range.

[0064] The pressure of the mixed gas during high-pressure treatment can be adjusted by adjusting the aperture of the regulating valve 261 at the start of supplying the mixed gas. For example, the larger the aperture of the regulating valve 261 at the start of supply, the higher the pressure of the mixed gas during high-pressure treatment. Even when the regulating valve 261 is quickly opened from the closed state to the standard aperture at the start of supplying the mixed gas, the pressure of the mixed gas acting on the zeolite membrane 12 temporarily becomes higher than the set pressure. The duration of high-pressure treatment can also be adjusted by adjusting the aperture of the regulating valve 261. For example, the longer the aperture of the regulating valve 261 is opened from the standard aperture, the longer the high-pressure treatment duration. The above operation achieves the same effect as high-pressure treatment even when the set pressure is changed for a short period of time. As described above, high-pressure treatment, which intentionally generates an overshoot at the start of supplying the mixed gas to the zeolite membrane 12, removes unwanted substances (such as moisture and hydrocarbon components in the air) adhering to the zeolite membrane 12.

[0065] When the regulating valve 261 is controlled based on the pressure gauge value, a time lag for the pressure to stabilize due to a delayed response of the regulating valve 261 may be utilized to generate a pressure overshoot of the mixed gas at the start of the mixed gas supply. The pressure overshoot of the mixed gas may also be caused by a delayed response of a device other than the regulating valve 261. Furthermore, the high-pressure treatment may be performed by gradually opening the regulating valve 261 from a closed state to an opening larger than the standard opening at the start of the mixed gas supply. In this case, too, during the period when the opening is larger than the standard opening, the pressure of the mixed gas acting on the zeolite membrane 12 becomes higher than the set pressure, thereby removing unwanted substances adhering to the zeolite membrane 12. Furthermore, the regulating valve 261 may be controlled based on the pressure gauge value so that the pressure of the mixed gas becomes higher than the set pressure. The high-pressure treatment may be performed not only simultaneously with the start of the mixed gas supply, but also in association with the start of the mixed gas supply.

[0066] The pressure of the mixed gas during high-pressure treatment is, for example, 10 times or less the set pressure. This more reliably prevents damage to the separation device 2 due to excessive high pressure. The pressure of the mixed gas during high-pressure treatment 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 treatment time, i.e., the time during which the pressure of the mixed gas is maintained higher than the set pressure, is, for example, 0.1 to 10,000 seconds. To more reliably remove unnecessary substances adhering to the zeolite membrane 12, the high-pressure treatment 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 to remove unnecessary substances, the high-pressure treatment time is preferably 300 seconds or less, more preferably 100 seconds or less, and even more preferably 30 seconds or less. Note that during high-pressure treatment, separation of highly permeable substances is performed in parallel.

[0067] In the high-pressure treatment, when the ratio of the pressure during the high-pressure treatment to the burst pressure (described below), which is the pressure at which the zeolite membrane 12 is broken in a short time, (pressure during the high-pressure treatment / breakdown pressure) is substituted for A in Equation 2, and the time of the high-pressure treatment is substituted for t to calculate the life consumption rate [%] for one high-pressure treatment, the life consumption rate is preferably 0.1% or less. The life consumption rate is more preferably 0.01% or less, and even more preferably 0.001% or less. This allows the life consumption to be appropriately suppressed, as described below. There is no particular lower limit to the life consumption rate (greater than 0%). The derivation of Equation 2 will be described later.

[0068]

[0069] When the pressure is not constant during high-pressure treatment (for example, when the above-mentioned overshoot occurs), it is preferable to substitute a value obtained by dividing the maximum pressure during high-pressure treatment 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 calculated by Equation 2. For example, the pressure during high-pressure treatment (the above-mentioned maximum pressure) is measured by a pressure gauge provided in the supply pipe 26. When high-pressure treatment is performed under constant conditions, if the pressure during high-pressure treatment under those conditions is known, the life consumption rate may be calculated using the known pressure without measuring the pressure. The same applies to the time of high-pressure treatment.

[0070] After the high-pressure treatment is completed, the separation device 2 is operated normally (step S12). In normal operation, the pressure of the mixed gas acting on the zeolite membrane 12 is set to a constant set pressure, and in this state, the highly permeable substances in the mixed gas are separated from the less permeable substances. The set pressure is preferably 0.1 MPaG (gauge pressure) to 8 MPaG. Since the unnecessary substances adhering to the zeolite membrane 12 are removed in the high-pressure treatment, the amount of highly permeable substances passing through the zeolite membrane composite 1 increases.

[0071] As described above, the standard opening is a guideline for the opening of the regulating valve 261 for supplying the mixed gas at the set pressure, and in normal operation, the regulating valve 261 is adjusted to approximately the standard opening. If the opening of the regulating valve 261 is set to the standard opening when the supply of the mixed gas starts, the flow of the mixed gas in the supply pipe 26 will reach a steady state after the start of the supply of the mixed gas, and the mixed gas will reach the set pressure. The regulating valve 261 may be controlled based on the value of the pressure gauge so that the pressure of the mixed gas will reach the set pressure.

[0072] When normal operation of the separation device 2 is stopped for maintenance or the like, it is preferable to perform a process similar to step S11 when normal operation is resumed after the maintenance or the like is completed. That is, when the supply of the mixed gas to the zeolite membrane 12 starts upon resuming normal operation, high-pressure treatment is performed similarly to the above. Also, high-pressure treatment may be performed by temporarily increasing the opening of the control valve 261 from the standard opening during normal operation, thereby removing unwanted substances adhering to the zeolite membrane 12. In this case, too, it is preferable to determine the pressure and time during high-pressure treatment so that the life consumption rate [%] in one high-pressure treatment is 0.1% or less.

[0073] Here, the lifetime consumption rate of the zeolite membrane 12 will be described. Before operating the separation device 2, an experiment is conducted to use the formula for the lifetime consumption rate in high-pressure treatment (Equation 2). Specifically, multiple zeolite membrane composites are prepared under the same conditions as the zeolite membrane composite 1 to be installed in the separation device 2. Each zeolite membrane composite is placed in a kiln, where the zeolite membrane is regenerated by heating. For example, the zeolite membrane is regenerated by heating the composite from room temperature to 380°C in an air atmosphere over 15.2 hours (heating rate: 25°C / hr), maintaining the temperature at 380°C for 8 hours, and then cooling to room temperature over 15.2 hours (cooling rate: 25°C / hr). This removes unwanted substances (such as moisture and hydrocarbon components in the air) adhering to the zeolite membrane 12.

[0074] The zeolite membrane composite is removed from the furnace and placed in the housing 22 shown in FIG. 1. Then, gas separation measurements are performed using the zeolite membrane composite. In the gas separation measurements, for example, CO ２ and C.H. ４ A mixed gas in which these are mixed at a volume ratio of 50:50 is used. The temperature during measurement is 25°C, the supply pressure is 0.3 MPaG, and the permeation pressure is 0 MPaG. CO ２ Permeation rate and CH ４ The permeation amount is obtained, and CH ４ CO permeation rate ２ The ratio of the amount of permeation (CO ２ Transmission amount / CH ４The separation ratio is the separation ratio before the application of pressure, which will be described later, and is hereinafter referred to as the "initial separation ratio."

[0075] Next, pressure is applied to the zeolite membrane. In applying pressure, water is supplied from the supply port 221 into the housing 22 at a constant pressure, and pressure is applied to the zeolite membrane of the zeolite membrane composite. After pressure is applied to the zeolite membrane for a predetermined period of time, the zeolite membrane composite is removed from the housing 22. The zeolite membrane composite is placed in a kiln, and the zeolite membrane is regenerated by heating in the same manner as above. After the zeolite membrane is regenerated, gas separation measurements are performed to determine the separation ratio after pressure application.

[0076] The above-described pressure application, zeolite membrane regeneration by heating, and gas separation measurement were repeated for each zeolite membrane composite. The applied pressure for each zeolite membrane composite was constant, and the applied pressure duration was appropriately adjusted. The applied pressures varied among the multiple zeolite membrane composites. When the separation ratio after pressure application fell to 10% or less of the initial separation ratio, the zeolite membrane of the zeolite membrane composite was deemed to have reached its end of life, and the sum of the applied pressure durations up to that point was determined as the zeolite membrane lifetime at that applied pressure. In this experiment, very high applied pressures were also used, and the applied pressure resulting in a lifetime of 1 second or less was determined as the breakdown pressure (also referred to as internal pressure breakdown strength). When the lifetime was 1 second or less at multiple applied pressures, the minimum applied pressure was determined as the breakdown pressure. From the above, the lifetime and breakdown pressure for the zeolite membrane 12 at each applied pressure were obtained.

[0077] Next, the ratio of each applied pressure to the burst pressure (applied pressure / burst pressure) is A, and the life time at that applied pressure is L [seconds]. The relationship between the ratio A and the life time L is expressed as log １０ L = log １０The values ​​of a and b in the case of A + b are determined by the least squares method. In other words, in a double logarithmic graph where the vertical axis represents log L and the horizontal axis represents log A, the slope a and intercept b of the approximation line showing the relationship between log L and log A are determined. a and b are characteristic values ​​derived from the type and structure of the zeolite membrane.

[0078] The above formula is L = A ａ x10 ｂ The life consumption rate [%] in one high-pressure treatment is the ratio of the time t of one high-pressure treatment to the life L, and can be calculated by (t / L) x 100. Here, L = A ａ x10 ｂ By substituting the above, the life consumption rate [%] in one high-pressure treatment is expressed as the above formula 2. As mentioned above, A in formula 2 is the ratio of the pressure during high-pressure treatment to the burst pressure. When 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 formula 3.

[0079]

[0080] Next, experimental examples 1 to 8 of high-pressure treatment will be described with reference to Table 1. In experimental examples 1 to 8, the pressure and time of the high-pressure treatment were changed. In Table 1, the "pressurization ratio" is the ratio of the pressure during high-pressure treatment to the set pressure during normal operation, and the "pressurization time" is the time of the 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 to 5 and 7 and experimental examples 6 and 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 the high-pressure treatment is performed. The "lifetime consumption rate" is the lifetime consumption rate including the number of times, and is calculated using Equation 3.

[0081]

[0082] In Experimental Examples 1 to 8, CO after high-pressure treatment ２ The amount of CO permeation was also measured. ２ and C.H. ４A mixed gas of these gases was used, and the temperature during measurement was 25°C, the supply pressure was 0.3 MPaG, and the permeation pressure was 0 MPaG. ２ The "permeation amount" is the CO permeation amount in Reference Example 1 where high pressure treatment is not performed. ２ CO permeation amount after high pressure treatment ２ "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 to 8, in which high-pressure treatment was performed, the relative CO ２ The permeation rate exceeded 100%, and the permeation performance of the zeolite membrane improved. In Experimental Examples 1 to 4, where the set pressure and pressurization time were the same, the relative CO ２ The permeation rate increased. Furthermore, the relative separation ratios for all of Experimental Examples 1 to 4 were 100 or greater. In Experimental Example 5, the pressurization time of Experimental Example 3 was extended 100 times, but the lifetime consumption rate was less than 0.1%, and the relative separation ratio was also 100 or greater. In Experimental Example 6, the pressurization rate and pressurization time were the same as in Experimental Example 1, but because Ratio A was higher, the lifetime consumption rate was significantly greater than 0.1%. In Experimental Example 7, the pressurization rate and Ratio A were the same as in Experimental Example 1, but because the pressurization time was extended 1,000,000 times, the lifetime consumption rate was significantly greater than 0.1%. In Experimental Examples 6 and 7, the relative separation ratios were less than 100. In Experimental Example 8, the pressurization time of Experimental Example 6 was extended 100 times, resulting in a lifetime consumption rate exceeding 100% and a significantly lower relative separation ratio.

[0084] As described above, the operating method of the separation device 2 includes a step (step S11) of performing normal operation in which a mixed gas containing multiple types of gases is supplied to a separation membrane (zeolite membrane 12 in the above example) at a constant set pressure, thereby separating substances in the mixed gas that have high separation membrane permeability from other substances, and a step (step S12) of performing 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 normal operation or during normal operation.

[0085] In the conventional operation method of a separation apparatus, the control valve 261 is gradually opened from a closed state to the standard opening when the mixed gas supply starts, so that the pressure of the mixed gas gradually increases to the set pressure. In other words, the mixed gas is not supplied to the separation membrane at a pressure higher than the set pressure. Furthermore, during normal operation, the pressure of the mixed gas is maintained at a constant set pressure. In contrast, in the above-described operation method of the separation apparatus 2, the mixed gas is intentionally set to a pressure higher than the set pressure when the mixed gas supply to the separation membrane starts or during normal operation. This allows the undesired substances adhering to the separation membrane to be removed using the mixed gas to be treated, and the permeation performance of the separation membrane (the increase in the permeation rate of highly permeable substances) can be easily achieved without using a heater or gases other than the mixed gas. Furthermore, the improvement in the permeation performance of the separation membrane also makes it possible to reduce the number of separation membrane assemblies provided in the separation apparatus 2.

[0086] Preferably, the relationship between the ratio A of the applied pressure to the burst pressure of the separation membrane and the lifetime L at the applied pressure is expressed as log １０ L = log １０ The values ​​of a and b in the formula A+b are determined in advance. Then, by substituting the ratio of the pressure during high-pressure treatment to the burst pressure for A in the above formula 2 using a and b, and substituting the time of high-pressure treatment for t, the life consumption rate [%] in one high-pressure treatment is obtained as 0.1% or less. This makes it possible to appropriately suppress the life consumption (damage) of the separation membrane during high-pressure treatment, and even when high-pressure treatment is repeated, it becomes possible to maintain a high relative separation ratio and extend the life of the separation membrane. As a result, the replacement cycle of the separation membrane composite can be extended (i.e., the number of replacements of the separation membrane composite in a given period can be reduced).

[0087] Preferably, in the separation device 2, a regulating valve 261 is provided between the mixed gas supply source 91 and the separation membrane. The standard opening of the regulating valve 261 for supplying the mixed gas to the separation membrane at a set pressure is obtained in advance, and when the supply of the mixed gas to the separation membrane begins, the opening of the regulating valve 261 is adjusted to an opening equal to or greater than the standard opening. This allows high-pressure treatment to be easily performed without providing a booster or the like in the supply pipe 26, resulting in space savings compared to when a booster or the like is provided. Depending on the pressure of the mixed gas supplied from the supply source 91, a booster or the like may be provided in the supply pipe 26.

[0088] Preferably, the set pressure is 0.1 MPaG to 8 MPaG, and the pressure during high-pressure treatment is 10 times or less the set pressure, thereby preventing damage to the separation device 2 due to the use of an excessively high pressure during high-pressure treatment.

[0089] Preferably, the high-pressure treatment time is 0.1 to 10,000 seconds, which allows removal of unwanted substances adhering to the separation membrane in a shorter time than when the separation membrane composite is removed from the housing 22 and heated in a furnace, as in the above-mentioned regeneration of the zeolite membrane by heating.

[0090] Preferably, the separation membrane is a zeolite membrane 12. This allows appropriate separation of mixed gases. Furthermore, when the maximum number of ring members 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 includes 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 in which the mixed gas is supplied to the separation membrane at a constant set pressure, and also performs 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 normal operation or during normal operation. This makes it possible to remove unnecessary substances adhering to the separation membrane and easily improve the permeation performance of the separation membrane.

[0092] The operating method of the separation device 2 and the separation device 2 can be modified in various ways.

[0093] In cases where the number of times high-pressure treatment is performed on the zeolite membrane 12 is small, the life consumption rate [%] per 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. Furthermore, the high-pressure treatment time may be longer than 10,000 seconds.

[0094] The supply of the mixed gas at a pressure higher than the set pressure to the zeolite membrane 12 may be achieved by using, for example, a blower or a booster provided in the supply pipe 26, in addition to adjusting the opening of the adjustment valve 261.

[0095] In the zeolite membrane composite 1, the zeolite membrane 12 may be formed on the outer peripheral surface of the support 11. As described above, the support 11 may be of a type other than a monolith.

[0096] The zeolite membrane composite 1 may further include a functional membrane or a protective membrane laminated on the zeolite membrane 12 in addition to the support 11 and the zeolite membrane 12. Such a functional membrane or protective membrane may be an inorganic membrane such as a zeolite membrane, a silica membrane, or a carbon membrane, or an organic membrane such as a polyimide membrane or a silicone membrane. In addition, the functional membrane or protective membrane laminated on the zeolite membrane 12 may contain a CO ２ A substance that easily adsorbs specific molecules such as the above may be added.

[0097] The type of zeolite constituting the zeolite membrane 12 may be changed as appropriate, and the maximum number of rings in the zeolite may be other than 8. As described above, the separation membrane may be other than the zeolite membrane 12.

[0098] In the separation device 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-described embodiment and each modification may be combined as appropriate as long as they are not mutually contradictory.

[0100] While the invention has been particularly illustrated and described, it should be understood that the foregoing description is illustrative and not restrictive, and that numerous modifications and variations are possible without departing from the scope of the invention.

[0101] The separation apparatus and the method for operating the separation apparatus according to the present invention can be used in various fields that use separation membranes.

[0102] 2 Separation device 12 Zeolite membrane 20 Control unit 260 Supply unit S11, S12 Steps

Claims

1. A method for operating a separation device using a separation membrane, comprising: a step of performing normal operation 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 a high permeability through the separation membrane from other substances; and a step of 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.

2. A method for operating a separation apparatus according to claim 1, wherein the relationship between the ratio A of the applied pressure to the breakdown pressure of the separation membrane and the life time L at the applied pressure is calculated by logarithm １０ L = log １０ A method for operating a separation device, wherein the values ​​of a and b in the formula A+b are determined in advance, and the life consumption rate [%] in one high-pressure treatment is obtained by substituting the ratio of the pressure during the high-pressure treatment to the burst pressure for A and substituting the time of the high-pressure treatment for t in the following formula using a and b, and wherein the life consumption rate [%] in one high-pressure treatment is 0.1% or less.

3. A method for operating a separation apparatus according to claim 1 or 2, wherein the set pressure is 0.1 MPaG to 8 MPaG, and the pressure during the high-pressure treatment is 10 times or less the set pressure.

4. A method for operating a separation apparatus according to claim 1 or 2, wherein the high-pressure treatment time is 0.1 to 10,000 seconds.

5. A method for operating a separation apparatus according to claim 1 or 2, wherein the separation membrane is a zeolite membrane.

6. A method for operating a separation apparatus according to claim 5, wherein the maximum number of rings of the zeolite constituting the zeolite membrane is eight.

7. 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 that have high permeability through 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 that performs high-pressure treatment in which the mixed gas is supplied to the separation membrane at a pressure higher than the set pressure when supply of the mixed gas to the separation membrane begins before the normal operation or during the normal operation.