Method for operating separation device, and separation device

Abstract

This operation method for a separation device using a separation membrane comprises: a step (step S12) in which a mixed gas containing a plurality of types of gases is supplied to the separation membrane at a certain set pressure, thereby separating substances from other substances in the mixed gas having high permeability of the separation membrane; and a step (step S11) for 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 is started before the normal operation or during the normal operation. As a result, unnecessary substances adhering to the separation membrane can be removed, and the permeability of the separation membrane can be easily improved.

Description

Technical Field

[0001] The invention relates to an operating method of a separation device and a separation device.

[0002] [References to related applications]

[0003] This application claims the benefit of priority of Japanese patent application JP2022-92971 filed on June 8, 2022, and the entire disclosure of that application is incorporated into this application. Background Art

[0004] In the past, methods for improving the permeability of separation membranes have been discussed. Japanese Patent Publication No. 2012-236123 (Document 1) discloses the following method: heating and drying at a temperature of 100 to 600 ° C to remove the crystal water of the FAU type zeolite membrane, and then maintaining a dry state, thereby obtaining a high permeability of carbon dioxide. In addition, International Publication No. 2018 / 180210 (Document 2) discloses a method for regenerating a zeolite membrane. In this method, the zeolite membrane that contacts the hydrocarbon mixture is pressurized in a state exposed to an inert gas atmosphere, and then the atmosphere is heated. In the regeneration method of the separation module in Japanese Patent Publication No. 2018-183756 (Document 3), the raw mixed gas is supplied to the separation module and separated into a permeable gas and a non-permeable gas, and the permeable gas is supplied to the separation module or another separation module in a state where the supply of the raw mixed gas has been stopped, thereby removing impurities attached to the hollow fiber membrane.

[0005] However, the separation membrane is usually transported from the time it is manufactured until it is actually used. In addition, the separation membrane is sometimes stored for a long time before it is used. During transportation or long-term storage, moisture, hydrocarbon components in the air, etc., that is, unwanted substances, sometimes adhere to the separation membrane and cause clogging of part of the pores of the separation membrane, thereby reducing the permeability of the separation membrane. When the unwanted substances are removed by heating as in Document 1, a heater is required. In addition, the life of the separation membrane may be consumed due to heating at high temperatures. When an inert gas is used for heating and pressurization as in Document 2, a heater is required as in Document 1 above, and an inert gas needs to be prepared. When the separation membrane is regenerated using a permeated gas that has passed through the separation membrane as in Document 3, two production lines (series) each including the separation membrane are required, which increases the size of the device and the space and cost. Summary of the invention

[0006] An object of the present invention is to easily improve the permeability of a separation membrane.

[0007] The invention of Scheme 1 is a method for operating a separation device using a separation membrane, which includes the following steps: a normal operation step, in which a mixed gas containing multiple types of gases is supplied to the separation membrane at a certain set pressure to separate substances in the mixed gas with high permeability of the separation membrane from other substances; and a high-pressure treatment step, in which the mixed gas is supplied to the separation membrane at a pressure higher than the set pressure when the mixed gas is supplied to the separation membrane before the normal operation or during the normal operation.

[0008] 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.

[0009] The invention of claim 2 is based on the method for operating the separation device of claim 1, wherein, with respect to the separation membrane, the relationship between the ratio A of the external pressure to the breaking pressure and the life time L under the external pressure is calculated in advance in terms of log 10 L=alog 10 When the values ​​of a and b are expressed by A+b, the life consumption rate [%] in one high-pressure treatment obtained by substituting the ratio of the pressure during the high-pressure treatment to the bursting pressure into A in the following formula using the a and b, and substituting t into the time of the high-pressure treatment is less than 0.1%.

[0010] [Mathematical formula 1]

[0011]

[0012] The invention of claim 3 is based on the operating method of the separation device of 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 of the set pressure.

[0013] The invention according to claim 4 is the method for operating a separation device according to any one of claims 1 to 3, wherein the time of the high pressure treatment is 0.1 to 10,000 seconds.

[0014] The invention according to claim 5 is the method for operating a separation device according to any one of claims 1 to 4, wherein the separation membrane is a zeolite membrane.

[0015] The invention according to claim 6 is based on the method for operating the separation device according to claim 5, wherein the maximum number of rings of zeolite constituting the zeolite membrane is eight.

[0016] The invention of Scheme 7 is a separation device comprising: a separation membrane; a supply unit, which separates substances in the mixed gas with high permeability of the separation membrane from other substances by supplying a mixed gas containing multiple types of gases to the separation membrane; and a control unit, which controls the supply unit to perform normal operation of supplying the mixed gas to the separation membrane at a certain set pressure, and performs high-pressure treatment of supplying the mixed gas to the separation membrane at a pressure higher than the set pressure when the mixed gas is supplied to the separation membrane before the normal operation or during the normal operation.

[0017] The above-mentioned object and other objects, features, aspects and advantages will become more apparent from the following detailed description of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a diagram showing the structure of a separation device.

[0019] Figure 2 is a cross-sectional view of a zeolite membrane composite.

[0020] Figure 3 This is a cross-sectional view showing an enlarged portion of a zeolite membrane composite.

[0021] Figure 4 It is a diagram showing the operation flow of the separation device. DETAILED DESCRIPTION

[0022] Figure 1 It is a diagram showing the structure of a separation device 2 according to one embodiment of the present invention. Figure 1 The parallel oblique lines at the cross section of a part of the structure are omitted. The separation device 2 is a device for separating a substance with high permeability (high permeability substance) of the zeolite membrane 12 described later from a mixed gas containing multiple types of gases. The purpose of separation in the separation device 2 can be, for example, to extract a substance with high permeability from the mixed gas, or to concentrate a substance with low permeability.

[0023] 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, thiols, 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.

[0024] Nitrogen oxides are compounds of nitrogen and oxygen. The above-mentioned nitrogen oxides are such as nitric oxide (NO), nitrogen dioxide (NO2), nitrous oxide (also known as dinitrogen monoxide) (N2O), dinitrogen trioxide (N2O3), dinitrogen tetroxide (N2O4), dinitrogen pentoxide (N2O5), etc., which are called NO X (Nox) gas.

[0025] Sulfur oxides are compounds of sulfur and oxygen. The above-mentioned sulfur oxides are sulfur dioxide (SO2), sulfur trioxide (SO3), etc., which are called SO X (Sox) gas.

[0026] Sulfur fluoride is a compound of fluorine and sulfur. The above-mentioned sulfur fluoride is, for example, sulfur difluoride (F-S-S-F, S=SF2), sulfur difluoride (SF2), sulfur tetrafluoride (SF4), sulfur hexafluoride (SF6) or sulfur decafluoride (SF6). 10 )wait.

[0027] C1 to C8 hydrocarbons are hydrocarbons having 1 or more and 8 or less carbon atoms. C3 to C8 hydrocarbons may be any of straight chain compounds, side chain compounds, and cyclic compounds. In addition, C2 to C8 hydrocarbons may be any of saturated hydrocarbons (i.e., hydrocarbons having no double bonds and triple bonds in the molecule) and unsaturated hydrocarbons (i.e., hydrocarbons having double bonds and / or triple bonds in the molecule). C1 to C4 hydrocarbons are, for example, methane (CH4), ethane (C2H6), ethylene (C2H4), propane (C3H8), propylene (C3H6), n-butane (CH3(CH2)2CH3), isobutane (CH(CH3)3), 1-butene (CH2=CHCH2CH3), 2-butene (CH3CH=CHCH3), or isobutene (CH2=C(CH3)2).

[0028] The above-mentioned organic acid is a carboxylic acid or a sulfonic acid, etc. Carboxylic acid is, for example, formic acid (CH2O2), acetic acid (C2H4O2), oxalic acid (C2H2O4), acrylic acid (C3H4O2) or benzoic acid (C6H5COOH), etc. Sulfonic acid is, for example, ethanesulfonic acid (C2H6O3S), etc. The organic acid may be a chain compound or a cyclic compound.

[0029] The above-mentioned alcohol is, for example, methanol (CH3OH), ethanol (C2H5OH), isopropyl alcohol (2-propanol) (CH3CH(OH)CH3), ethylene glycol (CH2(OH)CH2(OH)) or butanol (C4H9OH).

[0030] Thiols are organic compounds having hydrogenated sulfur (SH) at the end, and are also called Thiol or Thioalcohol. Examples of the thiols include methyl mercaptan (CH3SH), ethyl mercaptan (C2H5SH), and 1-propanethiol (C3H7SH).

[0031] The above-mentioned ester is, for example, formates or acetates.

[0032] The above-mentioned ether is, for example, dimethyl ether ((CH3)2O), methyl ethyl ether (C2H5OCH3) or diethyl ether ((C2H5)2O).

[0033] The above-mentioned ketone is, for example, acetone ((CH3)2CO), methyl ethyl ketone (C2H5COCH3) or diethyl ketone ((C2H5)2CO).

[0034] The above-mentioned aldehyde is, for example, acetaldehyde (CH3CHO), propionaldehyde (C2H5CHO) or butyraldehyde (Butyraldehyde) (C3H7CHO).

[0035] Figure 1 The separation device 2 includes a separation module 21, a supply pipe 26, a first recovery pipe 27, and a second recovery pipe 28. The separation module 21 includes a zeolite membrane complex 1, a housing 22, and two sealing components 23. The zeolite membrane complex 1 and the sealing components 23 are accommodated in the housing 22. The supply pipe 26, the first recovery pipe 27, and the second recovery pipe 28 are arranged outside the housing 22 and connected to the housing 22.

[0036] Figure 2 It is a cross-sectional view of the zeolite membrane composite 1 . Figure 3 This is a cross-sectional view showing a part of the zeolite membrane composite 1 in an enlarged manner. Figure 2 The sealing portion 13 described later is omitted in the figure. The zeolite membrane complex 1 is a separation membrane complex, which comprises: a porous support 11, and a zeolite membrane 12 as a separation membrane provided on the support 11. The so-called zeolite membrane 12 is a membrane in which zeolite is formed in a film shape at least on the surface of the support 11, and does not include a membrane obtained by simply dispersing zeolite particles in an organic membrane. In addition, the separation membrane 12 may also include two or more zeolites having different structures and compositions. Figure 2 The zeolite membrane 12 is depicted in bold. Figure 3 In FIG. 1 , parallel oblique lines are marked on the zeolite membrane 12. Figure 3 In FIG. 1 , the thickness of the zeolite membrane 12 is drawn thicker than the actual thickness.

[0037] It should be noted that in the separation device 2, a separation membrane complex other than the zeolite membrane complex 1 may be used, and an inorganic membrane formed of an inorganic substance other than zeolite or a membrane other than an inorganic membrane may be formed as a separation membrane on the support 11 instead of the zeolite membrane 12. In addition, a separation membrane in which zeolite particles are dispersed in an organic membrane may also be used. In the following description, the separation membrane is the zeolite membrane 12.

[0038] The support 11 is a porous member through which gas and liquid can pass. Figure 2 In the example shown, the support body 11 is: an integrally formed columnar main body is provided with two Figure 2 An integral support body having a plurality of through holes 111 extending in the left and right directions. Figure 2 In the example shown, the support body 11 is substantially cylindrical, and each through hole 111 (that is, cell) has a substantially circular cross section perpendicular to the longitudinal direction. Figure 2 In FIG. 1 , the diameter of the through hole 111 is drawn larger than the actual diameter, and the number of the through holes 111 is drawn less than the actual number. The zeolite membrane 12 is formed on the inner peripheral surface of the through hole 111 and covers substantially the entire inner peripheral surface of the through hole 111 .

[0039] The length of the support 11 (i.e., Figure 2 The length in the left-right direction in the through hole 11 is, for example, 10 cm to 200 cm. The outer diameter of the support body 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 body 11 is, for example, 0.1 μm to 5.0 μm, preferably 0.2 μm to 2.0 μm. It should be noted that the shape of the support body 11 can be, for example, a honeycomb, a flat plate, a tubular, a cylindrical, a cylindrical or a polygonal column. When the shape of the support body 11 is tubular or cylindrical, the thickness of the support body 11 is, for example, 0.1 mm to 10 mm.

[0040] The material of the support 11 can be any material that is chemically stable in the process of forming the zeolite film 12 on the surface, and various substances (such as ceramics or metals) can be used. In the present embodiment, the support 11 is formed by a ceramic sintered body. As the ceramic sintered body selected as the material of the support 11, for example, there can be cited: alumina, silica, mullite, zirconium dioxide, titanium dioxide, yttrium trioxide, silicon nitride, silicon carbide, etc. In the present embodiment, the support 11 contains at least one of alumina, silica and mullite.

[0041] The support 11 may contain an inorganic binder. As the inorganic binder, at least one of titanium dioxide, mullite, sinterable alumina, silicon dioxide, glass frit, clay mineral, and sinterable cordierite may be used.

[0042] 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 of the zeolite membrane 12 to be formed is 0.01 μm to 1 μm, preferably 0.05 μm to 0.5 μm. The average pore diameter can be measured using, for example, a mercury porosimeter, a pore size distribution meter, or a nanopore size distribution meter. Regarding the overall pore size distribution of the support 11, including the surface and the 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 of the zeolite membrane 12 to be formed is, for example, 20% to 60%.

[0043] The support 11 has, for example, a multilayer structure in which a plurality of layers having different average pore diameters are stacked in the thickness direction. The average pore diameter and sintered particle diameter in the surface layer including the surface on which the zeolite membrane 12 is to be formed are smaller than the average pore diameter and sintered particle diameter in the layer 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 use the above-mentioned materials. The materials of the multiple layers forming the multilayer structure may be the same or different.

[0044] The zeolite membrane 12 is a porous membrane having micropores. The zeolite membrane 12 can be used as a separation membrane that separates a specific substance from a fluid obtained by mixing multiple types of substances using a molecular sieving effect. In the zeolite membrane 12, other substances are difficult to penetrate compared to the specific substance. In other words, the permeation amount of the other substance of the zeolite membrane 12 is smaller than the permeation amount of the above-mentioned specific substance.

[0045] 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. If the zeolite membrane 12 is thickened, the separation performance is improved. If the zeolite membrane 12 is thinned, the permeation amount increases. 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 further preferably 0.5 μm or less.

[0046] The pore size of the zeolite membrane 12 is, for example, less than 1 nm. The pore size of the zeolite membrane 12 is preferably greater than 0.2 nm and less than 0.8 nm, more preferably greater than 0.3 nm and less than 0.7 nm, and further preferably greater than 0.3 nm and less than 0.45 nm. If the pore size is greater than 1 nm, the separation performance may sometimes decrease. In addition, if the pore size is less than 0.2 nm, the permeation amount may sometimes decrease. The pore size of the zeolite membrane 12 is smaller than the average pore size of the support 11 near the surface where the zeolite membrane 12 is to be formed.

[0047] When the maximum number of rings of the zeolite constituting the zeolite membrane 12 is n, the short diameter of the n-membered ring pore is taken as the pore diameter. In addition, when the zeolite has a plurality of n-membered ring pores having equal n numbers, the short diameter of the n-membered ring pore having the largest short diameter is taken as the pore diameter of the zeolite membrane 12. The n-membered ring pore refers to a pore in which the number of oxygen atoms in the portion where the oxygen atom is bonded to the T atom described later to form a ring structure is n. In this way, the pore diameter of the zeolite membrane is uniquely determined by the skeleton structure of the zeolite, and can be solved based on the values ​​disclosed in the "Database of Zeolite Structures" [online] of the International Zeolite Association and the website <URL: http: / / www.iza-structure.org / databases / >.

[0048] The type of zeolite constituting the zeolite membrane 12 is not particularly limited, and may be, for example, AEI, AEN, AFN, AFV, AFX, BEA, CHA, DDR, ERI, ETL, FAU (X, Y), GIS, LEV, LTA, MEL, MFI, MOR, PAU, RHO, SAT, SOD, or the like.

[0049] The zeolite membrane 12 includes silicon (Si), for example. The zeolite membrane 12 may include any two or more of Si, aluminum (Al), and phosphorus (P), for example. In this case, as the zeolite constituting the zeolite membrane 12, a zeolite in which the atom (T atom) located at the center of the oxygen tetrahedron (TO4) constituting the zeolite is only Si, or a zeolite in which the T atom includes Si and Al, an AlPO-type zeolite in which the T atom includes Al and P, a SAPO-type zeolite in which the T atom includes Si, Al, and P, a MAPSO-type zeolite in which the T atom includes magnesium (Mg), Si, Al, and P, a ZnAPSO-type zeolite in which the T atom includes zinc (Zn), Si, Al, and P, etc. can be used. A part of the T atom may be replaced by other elements.

[0050] When the zeolite membrane 12 contains Si atoms and Al atoms, the Si / Al ratio in the zeolite membrane 12 is, for example, greater than 1 and less than 100,000. The Si / Al ratio is preferably greater than 5, more preferably greater than 20, and further preferably greater than 100, and the higher the ratio, the more ideal it is. The Si / Al ratio in the zeolite membrane 12 can be adjusted by adjusting the mixing ratio of the Si source and the Al source in the raw material solution described later. The zeolite membrane 12 may contain an alkali metal. The alkali metal is, for example, sodium (Na) or potassium (K).

[0051] From the viewpoint of increasing the permeation amount of CO2 and improving the separation performance, the maximum number of rings of 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 having a structure code of "DDR" as specified by the International Zeolite Society. In this case, the pore diameter of the zeolite constituting the zeolite membrane 12 is 0.36nm×0.44nm, and the pore diameter is 0.36nm.

[0052] The permeation rate of CO2 through the zeolite membrane 12 at 20°C to 400°C is, for example, 100 nmol / m 2 ·s·Pa or more. In addition, the CO2 permeation / CH4 leakage ratio (permeation ratio) of the zeolite membrane 12 at 20°C to 400°C is, for example, greater than 100. The permeation and permeation ratio are values ​​when the partial pressure difference of CO2 between the supply side and the permeation side of the zeolite membrane 12 is 1.5 MPa.

[0053] Here, an example of a manufacturing process of the zeolite membrane complex 1 is described. In the manufacture of the zeolite membrane complex 1, first, seed crystals for manufacturing the zeolite membrane 12 are prepared. For example, a powder of DDR type zeolite is generated by hydrothermal synthesis, and seed crystals are obtained from the zeolite powder. The zeolite powder can be used directly as a seed crystal, or the powder can be processed by pulverizing or the like to obtain a seed crystal.

[0054] Next, the porous support 11 is immersed in a dispersion in which seed crystals are dispersed, so that the seed crystals are attached to the support 11. Alternatively, the dispersion in which seed crystals are dispersed is brought into contact with a portion of the support 11 on which the zeolite membrane 12 is to be formed, so that the seed crystals are attached 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 methods.

[0055] The support 11 with the seed crystal attached is immersed in the raw material solution. For example, a Si source and a structure-directing agent (hereinafter also referred to as "SDA") are dissolved or dispersed in a solvent to prepare a raw material solution. The solvent of 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. As SDA, for example, 1-adamantanamine can be used.

[0056] Then, by hydrothermal synthesis, DDR type zeolite is grown with the seed crystal as a nucleus, 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.

[0057] 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 at, for example, 80° C. After the support 11 and the zeolite membrane 12 are dried, the zeolite membrane 12 is heated to burn and remove the SDA in the zeolite membrane 12 almost completely, so that the micropores in the zeolite membrane 12 are penetrated. Thus, the above-mentioned zeolite membrane composite 1 is obtained.

[0058] Figure 1 In an example of the zeolite membrane composite 1 shown, sealing portions 13 are provided at both ends of the support body 11 in the length direction. The sealing portion 13 is a component that covers and seals the two end faces of the support body 11 in the length direction and the outer peripheral surface near the two end faces. The sealing portion 13 prevents gas from flowing in and out of the two end faces of the support body 11. The sealing portion 13 is formed of, for example, glass, resin or metal. The material and shape of the sealing portion 13 can be appropriately changed. It should be noted that both ends of each through hole 111 in the length direction are not covered by the sealing portion 13, and gas can flow into and out of the through hole 111 through the two ends.

[0059] In the separation module 21, the housing 22 is, for example, a cylindrical member having a substantially cylindrical shape. The housing 22 may also be in a shape other than a cylindrical shape. The housing 22 is a pressure-resistant container, for example, formed of stainless steel or carbon steel. The length direction of the housing 22 is substantially parallel to the length direction of the zeolite membrane complex 1. At one end of the housing 22 in the length direction (i.e., Figure 1 A supply port 221 is provided at the left end of the housing 22, and a first discharge port 222 is provided at the other end. A second discharge port 223 is provided on the side of the housing 22. The supply port 221 is connected to a supply pipe 26. The first discharge port 222 is connected to a first recovery pipe 27. The second discharge port 223 is connected to a second recovery pipe 28. The internal space of the housing 22 is a closed space isolated from the space around the housing 22.

[0060] exist Figure 1In the example shown, the housing 22 includes a housing body 224 and two cover portions 226. The housing body 224 is a generally cylindrical member having openings at both ends in the longitudinal direction. Two flange portions 225 are provided on the housing body 224. The two flange portions 225 are respectively generally annular plate-shaped portions extending radially outward from the housing body 224 around the above-mentioned two openings of the housing body 224. The housing body 224 and the two flange portions 225 are integrally connected members. The two cover portions 226 are respectively fixed to the two flange portions 225 by bolting or the like in a state of covering the above-mentioned two openings of the housing body 224. Thereby, the two openings of the housing body 224 are hermetically sealed. The above-mentioned supply port 221 is provided at Figure 1 The first outlet 222 is provided at the left side of the cover 226. Figure 1 The second outlet 223 is provided at approximately the center of the housing body 224 in the longitudinal direction.

[0061] Two sealing members 23 are disposed entirely between the outer peripheral surface of the zeolite membrane composite 1 and the inner peripheral surface of the housing 22 near both ends in the longitudinal direction of the zeolite membrane composite 1. Each sealing member 23 is formed of a gas-impermeable material. Figure 1 In the example shown in FIG. 1 , the sealing member 23 is annular, for example, an O-ring formed of a flexible resin.

[0062] Each sealing 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 circumference. Figure 1 In the example shown, the sealing member 23 is in close contact with the outer peripheral surface of the sealing portion 13, and is indirectly in close contact with the outer peripheral surface of the support body 11 via the sealing portion 13. The sealing member 23 and the outer peripheral surface of the zeolite membrane complex 1 and the sealing member 23 and the inner peripheral surface of the housing 22 are sealed, and gas can hardly pass through or cannot pass through at all. In the separation module 21, the airtightness between the second discharge port 223 and the supply port 221 and the first discharge port 222 is ensured by the sealing member 23.

[0063] The supply pipe 26 connects the supply source 91 of the mixed gas and the separation module 21. The supply pipe 26 is provided with, for example, an adjustment valve 261 for adjusting the pressure of the mixed gas. The control unit 20 is electrically connected to the adjustment valve 261. The control unit 20 is a computer having, for example, a circuit or a CPU for control. The opening of the adjustment valve 261 is controlled by the control unit 20. A pressure gauge is provided in the supply pipe 26, and the adjustment valve 261 can be controlled (for example, feedback control) 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 shell 22 via the supply port 221. The supply pipe 26 may be provided with a blower or a pump for pressurizing the mixed gas toward the shell 22. The supply pipe 26 and the adjustment valve 261 are a supply unit 260 for supplying the mixed gas to the zeolite membrane complex 1.

[0064] The first recovery pipe 27 recovers the gas discharged from the first outlet 222. The second recovery pipe 28 recovers the gas discharged from the second outlet 223. The first recovery pipe 27 and the second recovery pipe 28 may be provided with a storage container for storing the recovered gas, or a blower or pump for transferring and transporting the gas.

[0065] In the separation device 2, a mixed gas containing multiple types of gases with different permeabilities 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 for separating the mixed gas is, for example, 10°C to 250°C.

[0066] The mixed gas supplied from the supply pipe 26 to the housing 22 is passed through the zeolite membrane composite 1 as indicated by arrows 251. Figure 1 The left end of the through hole 111 is introduced into each through hole 111 of the support body 11. The gas with high permeability in the mixed gas (for example, CO2, hereinafter referred to as "high permeability substance") passes through the zeolite membrane 12 and the support body 11 provided on the inner peripheral surface of each through hole 111 and is discharged from the outer peripheral surface of the support body 11. Thus, the high permeability substance is separated from the gas with low permeability (for example, CH4, hereinafter referred to as "low permeability substance") in the mixed gas.

[0067] The gas (hereinafter referred to as "permeated material") that permeates the zeolite membrane composite 1 and is discharged from the outer peripheral surface of the support body 11 is discharged to the second recovery pipe 28 through the second discharge port 223 as shown by the arrow 253 and recovered. The pressure of the gas discharged to the second recovery pipe 28 through the second discharge port 223 (i.e., the permeation pressure) is, for example, about 1 atmosphere (0.101 MPaA).

[0068] In addition, the gas in the mixed gas other than the gas that has permeated through the zeolite membrane composite 1 (hereinafter referred to as "non-permeable substances") is discharged from each through hole 111 of the support body 11. Figure 1 The non-permeable substance is discharged to the first recovery pipe 27 through the first discharge port 222 as shown by the arrow 252 and recovered. The pressure of the gas discharged to the first recovery pipe 27 through the first discharge port 222 is, for example, substantially the same as the supply pressure. The non-permeable substance may include a high permeability substance that does not pass through the zeolite membrane 12 in addition to the above-mentioned low permeability substance.

[0069] Figure 4 : is a diagram showing the operation flow of the separation device 2. During the operation of the separation device 2, first, the mixed gas is started to be supplied to the zeolite membrane complex 1. Here, in the separation device 2, in the normal operation described later, the target opening of the regulating valve 261 for supplying the mixed gas at a certain set pressure is obtained in advance as the standard opening. The standard opening is determined by experiment or experience. When the supply of the mixed gas starts, the control unit 20 is used to quickly (for example, within 10 seconds) open the regulating valve 261 from the closed state to an opening greater than the standard opening. As a result, the mixed gas flows violently from the supply source 91 through the supply pipe 26 into the housing 22. As a result, the pressure of the mixed gas acting on the zeolite membrane 12 is temporarily (for example, for several seconds) higher than the set pressure. That is, a high-pressure treatment (step S11) is performed to supply the mixed gas to the zeolite membrane 12 at a pressure higher than the set pressure. It should be noted that in normal operation, the pressure of the mixed gas changes to a certain extent around the set pressure. In this case, the pressure during the high-pressure treatment is preferably higher than the maximum value of its variation range.

[0070] The pressure of the mixed gas during high-pressure treatment can be adjusted by adjusting the opening of the adjustment valve 261 when the mixed gas starts to be supplied. For example, the larger the opening of the adjustment valve 261 at the start of supply, the higher the pressure of the mixed gas during high-pressure treatment. When the adjustment valve 261 is quickly opened from a closed state to a standard opening at the start of supplying the mixed gas, the pressure of the mixed gas acting on the zeolite membrane 12 will also temporarily be higher than the set pressure. In addition, the time of high-pressure treatment can also be adjusted by adjusting the opening of the adjustment valve 261. For example, the longer the opening of the adjustment valve 261 is greater than the standard opening, the longer the time of high-pressure treatment. Through the above operation, the operation of changing the set pressure in a short time also has the same effect as high-pressure treatment. In this way, when the mixed gas is started to be supplied to the zeolite membrane 12, the unnecessary substances (water, hydrocarbon components in the air, etc.) attached to the zeolite membrane 12 can be removed by using the high-pressure treatment that intentionally causes overshoot.

[0071] When the regulating valve 261 is controlled based on the value of the pressure gauge, it is also possible to use the fact that it takes time for the pressure to stabilize due to the response delay of the regulating valve 261 when the mixed gas starts to be supplied, so as to cause a pressure overshoot of the mixed gas. The pressure overshoot of the mixed gas can also be caused by the response delay of equipment other than the regulating valve 261. In addition, it is also possible to perform high-pressure treatment by slowly opening the regulating valve 261 from a closed state to an opening larger than the standard opening when the mixed gas starts to be supplied. In this case, during the period when the opening is larger than the standard opening, the pressure of the mixed gas acting on the zeolite membrane 12 will also be higher than the set pressure, and the unnecessary substances attached to the zeolite membrane 12 will be removed. In addition, the regulating valve 261 can also be controlled based on the value of the pressure gauge so that the pressure of the mixed gas is higher than the set pressure. High-pressure treatment can be performed not only at the same time as the start of the supply of the mixed gas, but also as the start of the supply of the mixed gas.

[0072] The pressure of the mixed gas during high-pressure treatment is, for example, less than 10 times the set pressure. Thus, damage to the separation device 2 caused by excessive high pressure can be more reliably prevented. The pressure of the mixed gas during high-pressure treatment is, for example, more than 1.1 times the set pressure, preferably more than 1.2 times, more preferably more than 1.3 times, and further preferably more than 1.5 times. The time of high-pressure treatment, that is, the time to maintain the pressure of the mixed gas higher than the set pressure, is, for example, 0.1 seconds to 10,000 seconds. In order to more reliably remove the unwanted substances attached to the zeolite membrane 12, the time of high-pressure treatment is preferably more than 1 second, more preferably more than 3 seconds, and further preferably more than 5 seconds. In order to shorten the time required to remove the unwanted substances, the time of high-pressure treatment is preferably less than 300 seconds, more preferably less than 100 seconds, and further preferably less than 30 seconds. It should be noted that during the high-pressure treatment, the separation of highly permeable substances is carried out simultaneously.

[0073] In the high-pressure treatment, the ratio of the pressure during the high-pressure treatment to the pressure at which the zeolite membrane 12 is destroyed in a short time, that is, the destruction pressure described later (pressure during the high-pressure treatment / destruction pressure) is substituted into A in Mathematical Formula 2, and the time of the high-pressure treatment is substituted into t to obtain the life consumption rate [%] in one high-pressure treatment. In this case, the life consumption rate is preferably 0.1% or less. The life consumption rate is more preferably 0.01% or less, and further preferably 0.001% or less. In this way, the life consumption can be appropriately suppressed. The lower limit of the life consumption rate is not particularly limited (greater than 0%). The derivation of Mathematical Formula 2 is explained below.

[0074] [Mathematical formula 2]

[0075]

[0076] When the pressure is not constant during high-pressure treatment (for example, when the overshoot described above is generated), it is preferred to substitute the value obtained by dividing the maximum pressure during high-pressure treatment by the breaking pressure into A of Mathematical Formula 2. In this case, the actual life consumption rate is smaller than the life consumption rate calculated using Mathematical Formula 2. For example, the pressure during high-pressure treatment (the above-mentioned maximum pressure) is measured using a pressure gauge provided on the supply pipe 26. When high-pressure treatment is performed under certain conditions, if the pressure during high-pressure treatment under the conditions is known, there is no need to measure the pressure, and the known pressure can be used to calculate the life consumption rate. The same is true for the time of high-pressure treatment.

[0077] When 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 certain set pressure. In this state, the high permeability substance in the mixed gas is separated from the low permeability substance. The set pressure is preferably 0.1 MPaG (gauge pressure) to 8 MPaG. By removing the unnecessary substances attached to the zeolite membrane 12 during the high pressure treatment, the permeation amount of the high permeability substance in the zeolite membrane complex 1 is increased.

[0078] As described above, the standard opening is the target opening of the regulating valve 261 for supplying the mixed gas at a set pressure. In normal operation, the regulating valve 261 is adjusted to approximately the standard opening. When the opening of the regulating valve 261 when the mixed gas supply starts is set to the standard opening, after the mixed gas supply starts, the flow of the mixed gas in the supply pipe 26 becomes a stable state, and thus the mixed gas reaches the set pressure. The regulating 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.

[0079] When the normal operation is stopped due to maintenance of the separation device 2, etc., when the normal operation is restarted after the maintenance, etc., it is preferable to perform the same process as the above step S11. That is, when the normal operation is restarted, when the mixed gas is started to be supplied to the zeolite membrane 12, the high-pressure treatment is performed in the same way as above. In addition, the high-pressure treatment can be performed by temporarily making the opening of the adjustment valve 261 larger than the standard opening during the normal operation to remove unnecessary substances attached to the zeolite membrane 12. In this case, it is also preferable to determine the pressure and time during the high-pressure treatment in such a way that the life consumption rate [%] in one high-pressure treatment is less than 0.1%.

[0080] Here, the life consumption rate of the zeolite membrane 12 is described. When the separation device 2 is operated, an experiment using the formula of the life consumption rate in high pressure treatment (the above-mentioned mathematical formula 2) is carried out in advance. Specifically, a plurality of zeolite membrane complexes produced under the same conditions as the zeolite membrane complex 1 set in the separation device 2 are prepared. Each zeolite membrane complex is placed in a kiln, and the zeolite membrane is regenerated by heating. In the regeneration of the zeolite membrane, for example, the temperature is raised from room temperature to 380°C (heating rate 25°C / hr) in an atmospheric atmosphere over 15.2 hours, maintained at 380°C for 8 hours, and cooled to room temperature over 15.2 hours (cooling rate 25°C / hr). In this way, unnecessary substances (water, hydrocarbon components in the air, etc.) attached to the zeolite membrane 12 are removed.

[0081] The zeolite membrane composite is taken out from the kiln and stored in Figure 1 in the housing 22. Then, the zeolite membrane composite is used to perform gas separation measurement. In the gas separation measurement, for example, a mixed gas obtained by mixing CO2 and CH4 at a ratio of 50:50 (volume ratio) is used. In addition, the temperature during the measurement is 25°C, the supply pressure is 0.3MPaG, and the permeation pressure is 0MPaG. Then, the CO2 permeation amount and the CH4 permeation amount are obtained based on the permeated material discharged from the second discharge port 223, and the ratio of the CO2 permeation amount to the CH4 permeation amount (CO2 permeation amount / CH4 permeation amount) is calculated as the separation ratio. This separation ratio is the separation ratio before the pressure is applied as described later, hereinafter referred to as the "initial separation ratio".

[0082] Next, pressure is applied to the zeolite membrane. During the pressure application, water is supplied from the supply port 221 into the housing 22 at a certain pressure, and pressure is applied to the zeolite membrane of the zeolite membrane complex. After the pressure is applied to the zeolite membrane for a predetermined time, the zeolite membrane complex is taken out from the housing 22. The zeolite membrane complex is placed in a kiln, and the zeolite membrane is regenerated by heating in the same manner as described above. After the zeolite membrane is regenerated, a gas separation measurement is performed to obtain the separation ratio after the pressure is applied.

[0083] For each zeolite membrane complex, the above-mentioned pressure application, zeolite membrane regeneration using heating and gas separation measurement are repeated. At this time, the external pressure applied to one zeolite membrane complex is constant, and the application time of the external pressure can be appropriately changed. In addition, the external pressure is different in multiple zeolite membrane complexes. It is assumed that when the separation ratio after the external pressure is less than 10% of the initial separation ratio, the zeolite membrane of the zeolite membrane complex reaches its life, and the sum of the application time of the external pressure until this moment is set as the life of the zeolite membrane under the external pressure. In this experiment, a very large external pressure is also used, and the external pressure with a life time of less than 1 second is obtained as the breaking pressure (also called internal pressure breaking strength). It should be noted that when the life time is less than 1 second under multiple external pressures, for example, the minimum external pressure is set as the breaking pressure. Based on this, for the zeolite membrane 12, the life time and breaking pressure under each external pressure are obtained.

[0084] Next, the relationship between the ratio A and the life time L was calculated by the least square method, where the ratio of each applied pressure to the burst pressure (applied pressure / burst pressure) was set as A, the life time under the applied pressure was set as L [seconds], and the relationship between the ratio A and the life time L was expressed as log 10 L=alog 10 The values ​​of a and b when A+b is expressed. In other words, in a double logarithmic curve where the vertical axis represents logL and the horizontal axis represents logA, the slope a and intercept b of the approximate straight line representing the relationship between logL and logA are calculated. a and b are inherent values ​​depending on the type and structure of the zeolite membrane.

[0085] The above formula can be transformed into L = A a ×10 b In addition, 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 is solved by (t / L)×100. Substituting L=A a ×10 b , thus, the life consumption rate [%] in one high pressure treatment is expressed as the above-mentioned mathematical formula 2. As mentioned above, A in mathematical formula 2 is the ratio of the pressure during high pressure treatment to the breaking pressure. When the pressure and time during high pressure treatment are kept the same and high pressure treatment is performed N times (N is an integer greater than 1), the life consumption rate [%] in N high pressure treatments is expressed by mathematical formula 3.

[0086] [Mathematical formula 3]

[0087]

[0088] Next, referring to Table 1, Experimental Examples 1 to 8 of high-pressure treatment are described. In Experimental Examples 1 to 8, the pressure and time of the high-pressure treatment were changed. The "pressurization ratio" in Table 1 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. It should be noted that the set pressure varies depending on the state of the supply source, etc., and therefore, the set pressure is different in Experimental Examples 1 to 5, 7 and Experimental Examples 6 and 8. "A" is the ratio of the pressure during high-pressure treatment to the breaking pressure, and the "number of times" is the number of times the high-pressure treatment is performed. The "life consumption rate" is the life consumption rate including the number of times, and is solved using Mathematical Formula 3.

[0089] [Table 1]

[0090]

[0091] In Experimental Examples 1 to 8, the permeation rate of CO2 after high pressure treatment was also measured. In the permeation rate measurement, a mixed gas obtained by mixing CO2 and CH4 at a volume ratio of 50:50 was used, the temperature during the measurement was set to 25°C, the supply pressure was set to 0.3 MPaG, and the permeation pressure was set to 0 MPaG. The "Relative CO2 Permeation Rate" in Table 1 is the ratio of the permeation rate of CO2 after high pressure treatment to the permeation rate of CO2 in Reference Example 1 without high pressure treatment. The "Relative Separation Ratio" is the ratio of the separation ratio after high pressure treatment to the separation ratio in Reference Example 1.

[0092] In Experimental Examples 1 to 8, which were subjected to high pressure treatment, the relative CO2 permeation was greater than 100%, and the permeation performance of the zeolite membrane was improved. In Experimental Examples 1 to 4, where the set pressure and pressurization time were the same, the higher the pressurization ratio, the higher the relative CO2 permeation. In addition, in Experimental Examples 1 to 4, the relative separation ratio was greater than 100. In Experimental Example 5, although the pressurization time of Experimental Example 3 was extended to 100 times, the life consumption rate was less than 0.1%, and the relative separation ratio was also greater than 100. In Experimental Example 6, the pressurization ratio and pressurization time were the same as those of Experimental Example 1, but because the ratio A was larger, the life consumption rate was greatly increased compared to 0.1%. In Experimental Example 7, the pressurization ratio and ratio A were the same as those of Experimental Example 1, but the pressurization time was extended to 1,000,000 times, so the life consumption rate was greatly increased compared to 0.1%. In Experimental Examples 6 and 7, the relative separation ratio was less than 100. In Experimental Example 8, the pressurization time of Experimental Example 6 was extended 100 times. As a result, the life consumption rate exceeded 100% and the relative separation ratio was greatly reduced.

[0093] As described above, the operating method of the separation device 2 includes the following steps: a normal operation step (step S11), 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 certain set pressure to separate substances in the mixed gas with high permeability of the separation membrane from other substances; and a high-pressure treatment step (step S12), in which the mixed gas is supplied to the separation membrane at a pressure higher than the set pressure when the mixed gas is supplied to the separation membrane before normal operation or during normal operation.

[0094] Here, in the previous operation method of the separation device, when the mixed gas is started to be supplied, the adjustment valve 261 is slowly opened from the closed state to the standard opening, so that the pressure of the mixed gas gradually increases to the set pressure. In other words, it is not a state in which the mixed gas is supplied to the separation membrane at a pressure higher than the set pressure. In addition, during normal operation, the pressure of the mixed gas is maintained at a certain set pressure. In contrast, in the above-mentioned operation method of the separation device 2, when the mixed gas is started to be supplied to the separation membrane or during normal operation, the mixed gas is intentionally set to a pressure higher than the set pressure. As a result, the unwanted substances attached to the separation membrane can be removed using the mixed gas to be treated, and the permeability of the separation membrane can be easily improved (the permeability rate of highly permeable substances is improved) without using a heater or a gas other than the mixed gas. In addition, by improving the permeability of the separation membrane, the number of separation membrane complexes provided in the separation device 2 can also be reduced.

[0095] Preferably, for the separation membrane, the relationship between the ratio A of the applied pressure to the rupture pressure and the life time L under the applied pressure is calculated in advance in terms of log 10 L=alog 10 The values ​​of a and b when A+b is expressed. Furthermore, the life consumption rate [%] in one high-pressure treatment obtained by substituting the ratio of the pressure during high-pressure treatment to the breaking pressure into A in the above mathematical formula 2 using a and b, and substituting the time of high-pressure treatment into t is 0.1% or less. Thus, the life consumption (damage) of the separation membrane during high-pressure treatment can be appropriately suppressed, and even in the case of repeated high-pressure treatment, a high relative separation ratio can be maintained to achieve a long life 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 specified period can be reduced).

[0096] Preferably, in the separation device 2, an adjustment valve 261 is provided between the supply source 91 of the mixed gas and the separation membrane. The standard opening of the adjustment valve 261 for supplying the mixed gas to the separation membrane at a set pressure is obtained in advance, and when the mixed gas starts to be supplied to the separation membrane, the opening of the adjustment valve 261 is adjusted to an opening above the standard opening. Thus, high-pressure processing can be easily performed without providing a booster or the like in the supply pipe 26, and as a result, space saving can be achieved compared to the case where a booster or the like is provided. A booster or the like may also be provided in the supply pipe 26 according to the pressure of the mixed gas supplied from the supply source 91 or the like.

[0097] Preferably, the set pressure is 0.1 MPaG to 8 MPaG, and the pressure during high pressure treatment is 10 times or less of the set pressure. This can prevent the separation device 2 from being damaged by using an excessively high pressure during high pressure treatment.

[0098] Preferably, the high pressure treatment time is 0.1 to 10,000 seconds. This allows the removal of unnecessary substances adhering to the separation membrane to be performed in a shorter time than when the separation membrane complex is taken out of the housing 22 and heated in a kiln as in the above-mentioned regeneration of the zeolite membrane by heating.

[0099] Preferably, the separation membrane is a zeolite membrane 12. This allows for appropriate separation of the mixed gas. In addition, 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.

[0100] The separation device 2 comprises: a separation membrane (a zeolite membrane 12 in the above example); a supply unit 260 for separating the mixed gas by supplying the mixed gas to the separation membrane; and a control unit 20 for performing normal operation of supplying the mixed gas to the separation membrane at a certain set pressure by controlling the supply unit 260, and performing high pressure treatment of supplying the mixed gas to the separation membrane at a pressure higher than the set pressure when the mixed gas is supplied to the separation membrane before the normal operation or during the normal operation. In this way, it is possible to remove unnecessary substances attached to the separation membrane and easily improve the permeability of the separation membrane.

[0101] The operating method of the separation device 2 and the separation device 2 described above can be modified in various ways.

[0102] In the case where the number of high pressure treatments on the zeolite membrane 12 is small, the life consumption rate [%] in one 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 the high pressure treatment may be greater than 10 times the set pressure. In addition, the time of the high pressure treatment may be longer than 10,000 seconds.

[0103] Supplying the mixed gas to the zeolite membrane 12 at a pressure higher than the set pressure can 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 regulating valve 261 .

[0104] 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 in a form other than the monolithic type.

[0105] The zeolite membrane composite 1 may further include a functional membrane or a protective membrane stacked on the zeolite membrane 12 in addition to the support 11 and the zeolite membrane 12. Such a functional membrane or a protective membrane may be an inorganic membrane such as a zeolite membrane, a silicon dioxide membrane or a carbon membrane, or an organic membrane such as a polyimide membrane or an organic silicon membrane. In addition, a substance that easily adsorbs specific molecules such as CO2 may be added to the functional membrane or the protective membrane stacked on the zeolite membrane 12.

[0106] The type of zeolite constituting the zeolite membrane 12 may be changed as appropriate, and the maximum number of ring members of the zeolite may be other than 8. As described above, the separation membrane may be a membrane other than the zeolite membrane 12 .

[0107] In the separation device 2 using the separation membrane, substances other than the substances exemplified in the above description can also be separated from the mixed gas.

[0108] The configurations in the above-described embodiment and each modified example may be appropriately combined unless they are mutually contradictory.

[0109] Although the invention has been described and illustrated in detail, the above description is illustrative rather than restrictive, and therefore, it can be understood that many modifications and variations may be employed without departing from the scope of the invention.

[0110] Industrial Applicability

[0111] The operating method of the separation device and the separation device according to the present invention can be used in various fields using separation membranes.

[0112] Explanation of symbols

[0113] 2 Separation device

[0114] 12 Zeolite membrane

[0115] 20. Control Unit

[0116] 260 Supply Department

[0117] Steps S11 and S12

Claims

1. A method for operating a separation device using a separation membrane, comprising the following steps: A step of performing a normal operation in which a mixed gas containing a plurality of types of gases is supplied to a separation membrane at a constant set pressure to separate a substance in the mixed gas having a high permeability to 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 when supplying the mixed gas to the separation membrane starts before the normal operation or during the normal operation.

2. The method for operating the separation device according to claim 1, characterized in that: The relationship between the ratio A of the applied pressure to the breaking pressure and the life time L under the applied pressure is calculated in advance as logarithm. 10 L=alog 10 When A+b is expressed, the values ​​of a and b are 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 into A in the following formula using the above a and b and substituting the time of the high pressure treatment into t is 0.1% or less, [Mathematical formula 1] 3. The method for operating a separation device according to claim 1 or 2, characterized in that: The set pressure is 0.1MPaG~8MpaG, The pressure during the high pressure treatment is 10 times or less of the set pressure.

4. The method for operating a separation device according to claim 1 or 2, characterized in that: The high pressure treatment time is 0.1 second to 10000 seconds.

5. The method for operating a separation device according to claim 1 or 2, characterized in that: The separation membrane is a zeolite membrane.

6. The method for operating the separation device according to claim 5, characterized in that: The maximum number of ring members of zeolite constituting the zeolite membrane is 8.

7. A separation device comprising: Separation membrane; a supply unit that supplies a mixed gas containing a plurality of types of gases to the separation membrane to separate a substance in the mixed gas having high permeability to the separation membrane from other substances; and A control unit that performs normal operation of supplying the mixed gas to the separation membrane at a certain set pressure by controlling the supply unit, and performs high-pressure treatment of 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 the normal operation or during the normal operation.

Images