JP7498034B2 - Separation device and method for operating the separation device - Google Patents

Description

The present invention relates to a separation device and a method for operating the separation device.

Currently, various research and development efforts are being conducted on the formation of zeolite membrane composites by forming zeolite membranes on porous supports, for the purpose of separating specific molecules and adsorbing molecules by utilizing the molecular sieving action of zeolite.

For example, Patent Documents 1 and 2 propose a technique for separating mixed gases using a zeolite membrane. Patent Document 3 discloses a method for using a gas separator fixed structure to separate gases at high temperatures of 100°C to 650°C.

Patent Documents 4 to 6 disclose separation membrane modules that separate water from a mixed liquid containing water and an organic solvent. In the separation membrane module, multiple tubular membrane separation members are arranged inside a cylindrical module body. Each membrane separation member includes a tubular zeolite separation membrane and an outer cylinder that surrounds the separation membrane. The mixed liquid flows through the cylindrical space between the separation membrane and the outer cylinder. The water in the mixed liquid permeates the separation membrane radially inward, passes through the space inside the separation membrane, and is discharged from the module body. The organic solvent in the mixed liquid passes through the space between the separation membrane and the outer cylinder, and is discharged from the module body.

Non-Patent Document 1 discloses a double-cylinder type separation membrane module in which a group of double cylindrical tubes is housed in a vacuum vessel. In each double cylindrical tube, the supply steam is passed through the cylindrical space between the outer tube and the inner tube (zeolite membrane), and components that have an affinity for the zeolite membrane permeate the inner tube radially inward. The steam that has permeated the inside of the inner tube flows out from the end of the outer tube (i.e., the end of the inner tube that is open only on one side) into the vacuum vessel, and is sucked in from an outlet provided near the outflow direction of the steam and discharged outside the vacuum vessel. In this module, a heater is provided in the vacuum vessel to prevent condensation of the supply steam.

Patent document 7 discloses a gas separation device that includes a separation membrane module with a gas separation membrane element in a housing, a case that contains the separation membrane module, and a heat source that adjusts the temperature inside the case.

JP 2003-159518 A JP 2015-044162 A JP 2011-189335 A JP 2009-039654 A JP 2009-066503 A JP 2009-226374 A JP 2019-084497 A

M. Kondo et.al., Separation and Purification Technology, 32 (2003) p191-198

When separating fluids at high temperatures in a separation membrane module as described above, it is necessary to heat the fluid supplied to the module in advance to a temperature higher than the separation temperature, taking into account heat radiation from the outer cylinder through which the fluid flows. Alternatively, as in Non-Patent Document 1 and Patent Document 7, it is necessary to heat the inside of the module or housing using an external heat source such as a heater. This requires a large amount of energy to heat the fluid, and the energy required for fluid separation increases. In particular, when the outer cylinder or the module body has a flange structure, the heat radiation area is large, and the above-mentioned heat radiation is large. Therefore, the energy required for fluid separation increases.

In addition, in Non-Patent Document 1, the exhaust port of the vacuum container is provided near the end of the outer cylinder from which the steam flows out so that the steam that has permeated the zeolite membrane and flowed out from the outer cylinder into the vacuum container can be quickly discharged. As a result, the steam that has permeated the zeolite membrane flows toward the outside of the vacuum container with almost no contact with the outer surface of the outer cylinder. Therefore, the separation membrane module of Non-Patent Document 1 is only slightly effective in suppressing the temperature drop of the outer cylinder due to heat radiation to the outside.

The present invention was developed in consideration of the above problems, and aims to reduce the energy required to separate fluids at high temperatures.

The present invention is directed to a separation device. A separation device according to a preferred embodiment of the present invention includes a separation membrane composite including a porous support and a separation membrane formed on a surface of the support, an outer cylinder that houses the separation membrane composite, an exterior body that houses the outer cylinder, and a supply unit that supplies a fluid having a temperature higher than the ambient temperature of the exterior body to the inside of the outer cylinder. The outer cylinder includes a first discharge port that discharges non-permeable substances, which are substances other than permeable substances that have permeated the separation membrane composite, from the fluid to the outside of the outer cylinder, and a second discharge port that discharges the permeable substances from the fluid to the outside of the outer cylinder. The first discharge port and the second discharge port are each provided on the outer cylinder inside the exterior body. One of the permeable substances and the non-permeable substances discharged from the outer cylinder can be introduced into an exterior space, which is a space between the exterior body and the outer cylinder inside the exterior body, through an introduction port that is one of the first discharge port and the second discharge port of the outer cylinder . The exterior body includes an exterior body discharge port capable of discharging the one substance introduced into the exterior space by the introduction port to the outside of the exterior body . An inter-port space, which is a space surrounded by the exterior body, the introduction port, and the exterior body discharge port, contains 50 volume % or more of the separation membrane composite. The inter-port space is an internal space of the exterior body, and is a space sandwiched between an introduction port plane and an exterior body discharge port plane that are parallel to each other. The introduction port plane is a plane that is perpendicular to a straight line connecting the center of the introduction port of the outer cylinder and the center of the exterior body discharge port, and that passes through the center of the introduction port. The exterior body discharge port plane is a plane that is perpendicular to the straight line, and that passes through the center of the exterior body discharge port.

Preferably, the exterior space exists at least in the normal direction to the main surface of the separation membrane.

Preferably, the outer cylinder comprises a tube portion having an opening at at least one end, a flange portion extending outward from the tube portion around the opening, and a lid portion that is fixed to the flange portion while covering the opening to seal the opening.

Preferably, the one material is the permeable material.

Preferably, the separation device further includes a heating unit that heats the fluid before it is supplied to the outer cylinder.

Preferably, the temperature of the fluid supplied by the supply unit is 70°C or higher.

Preferably, the separation device further includes a heat insulating section disposed around the exterior body to insulate at least a portion of the exterior surface of the exterior body.

Preferably, the separation membrane is a zeolite membrane.

Preferably, the maximum number of rings in the zeolite constituting the zeolite membrane is 8 or less.

Preferably, the fluid contains one or more of the following substances: hydrogen, helium, nitrogen, oxygen, water, water vapor, carbon monoxide, carbon dioxide, nitrogen oxides, ammonia, sulfur oxides, hydrogen sulfide, sulfur fluoride, mercury, arsine, hydrogen cyanide, carbonyl sulfide, C1-C8 hydrocarbons, organic acids, alcohols, mercaptans, esters, ethers, ketones, and aldehydes.

The present invention is also directed to a method for operating a separation device including a separation membrane composite including a porous support and a separation membrane formed on a surface of the support, an outer cylinder containing the separation membrane composite, and an exterior body containing the outer cylinder. The outer cylinder includes a first discharge port for discharging a non-permeating substance , which is a substance other than a permeating substance that has permeated the separation membrane composite, to the outside of the outer cylinder , and a second discharge port for discharging the permeating substance to the outside of the outer cylinder. The first discharge port and the second discharge port are each provided on the outer cylinder inside the exterior body. One of the permeating substance and the non-permeating substance discharged from the outer cylinder can be introduced into an exterior space, which is a space between the exterior body and the exterior cylinder inside the exterior body, through an introduction port that is one of the first discharge port and the second discharge port of the exterior cylinder. The exterior body includes an exterior body discharge port that can discharge the one substance introduced into the exterior space by the introduction port to the outside of the exterior body. The inter-port space, which is a space surrounded by the exterior body, the inlet port, and the exterior body outlet port, contains 50% by volume or more of the separation membrane composite. The inter-port space is an internal space of the exterior body, and is a space sandwiched between an inlet port plane and an exterior body outlet port plane which are parallel to each other. The inlet port plane is a plane perpendicular to a line connecting the center of the inlet port of the outer cylinder and the center of the exterior body outlet port, and passing through the center of the inlet port. The exterior body outlet port plane is a plane perpendicular to the line and passing through the center of the exterior body outlet port. A method for operating a separation device according to a preferred embodiment of the present invention includes the steps of: a) supplying a fluid having a temperature higher than the temperature around the exterior body to the inside of the outer cylinder; b) introducing one of the permeating substance and the non-permeating substance into the exterior space through the inlet port; and c) discharging the one of the permeating substance and the non-permeating substance from the exterior space so as to pass through the inter-port space.

The present invention can reduce the energy required to separate fluids at high temperatures.

FIG. 1 is a diagram showing a separation device according to a first embodiment. FIG. 2 is a cross-sectional view of a zeolite membrane composite. FIG. 2 is an enlarged cross-sectional view of a zeolite membrane composite. FIG. FIG. 1 is a diagram showing the separation flow of fluids. FIG. 13 is a diagram showing a separation device according to a second embodiment. FIG. FIG. 2 is a diagram showing a part of a separation flow of fluids. FIG. 13 shows another separation device. FIG. 13 shows another separation device. FIG. 13 shows another separation device. FIG. 13 shows another separation device.

Figure 1 is a diagram showing the schematic structure of a separation device 2 according to a first embodiment of the present invention. In Figure 1, the parallel diagonal lines in the cross sections of some components have been omitted (the same applies to Figures 4, 6, 7, and 9 to 12). The separation device 2 is a device that separates substances that are highly permeable to the zeolite membrane composite 1 described below from a fluid (i.e., gas or liquid). Separation in the separation device 2 may be performed, for example, for the purpose of extracting highly permeable substances from a fluid, or for the purpose of concentrating less permeable substances.

The above-mentioned fluid may be one type of gas or a mixed gas containing multiple types of gases, one type of liquid or a mixed liquid containing multiple types of liquids, or a gas-liquid two-phase fluid containing both gas and liquid.

The fluid may include one or more of the following substances: hydrogen ( _H2 ), helium (He), nitrogen ( _N2 ), oxygen ( _O2 ), water ( _H2O ), water vapor ( _H2O ), carbon monoxide (CO), carbon dioxide ( _CO2 ), nitrogen oxides, ammonia ( _NH3 ), sulfur oxides, hydrogen sulfide ( _H2S ), sulfur fluoride, mercury (Hg), arsine ( _AsH3 ), hydrogen cyanide (HCN), carbonyl sulfide (COS), C1-C8 hydrocarbons, organic acids, alcohols, mercaptans, esters, ethers, ketones, and aldehydes.

Nitrogen oxides are compounds of nitrogen and oxygen. Examples of the nitrogen oxides are gases called NOx (nox), such as nitric oxide (NO), nitrogen dioxide ( _NO2 ), _nitrous oxide (also called dinitrogen oxide) ( _N2O ), dinitrogen trioxide ( _N2O3 ), dinitrogen tetroxide ( _N2O4 ), _{and dinitrogen} pentoxide ( _{N2O5 )} .

Sulfur oxides are compounds of sulfur and oxygen. The above-mentioned sulfur oxides are, for example, gases called _SOx , such as sulfur dioxide ( _SO2 ) and sulfur trioxide ( _SO3 ).

Sulfur fluoride is a compound of fluorine and sulfur. Examples of the sulfur fluoride include disulfur difluoride (F-S-S-F, S=SF ₂ ), sulfur difluoride (SF ₂ ), sulfur tetrafluoride (SF ₄ ), sulfur hexafluoride (SF ₆ ), and disulfur decafluoride (S ₂ F ₁₀ ).

C1-C8 hydrocarbons are those having at least one carbon and no more than eight carbons. 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 having no double bonds or triple bonds in the molecule) or unsaturated hydrocarbons (i.e., those having double bonds and/or triple bonds in the molecule). C1-C4 hydrocarbons are, 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 ).

The organic acid may be a carboxylic acid or a sulfonic acid. The carboxylic acid may be, 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). The sulfonic acid may be, for example, ethanesulfonic acid (C ₂ H ₆ O ₃ S). The organic acid may be a chain compound or a cyclic compound.

The above-mentioned alcohols are, 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).

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

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

The above-mentioned ethers are, 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).

The above-mentioned ketones are, 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).

The above-mentioned aldehydes are, for example, acetaldehyde (CH ₃ CHO), propionaldehyde (C ₂ H ₅ CHO) or butanal (butyraldehyde) (C ₃ H ₇ CHO).

In the following description, the fluid separated by the separation device 2 is assumed to be a mixed substance containing multiple types of gas (i.e., a mixed gas).

The separation device 2 includes a zeolite membrane composite 1, a sealing section 21, an outer cylinder 22, two sealing members 23, an exterior body 24, a supply section 26, a first recovery section 27, and a second recovery section 28. The zeolite membrane composite 1, the sealing section 21, and the sealing members 23 are housed inside the outer cylinder 22. The outer cylinder 22 is housed inside the exterior body 24. The supply section 26, the first recovery section 27, and the second recovery section 28 are disposed outside the exterior body 24.

Figure 2 is a cross-sectional view of the zeolite membrane composite 1. Figure 3 is a cross-sectional view showing an enlarged portion of the zeolite membrane composite 1. The zeolite membrane composite 1 is a separation membrane composite including a porous support 11 and a zeolite membrane 12, which is a separation membrane formed 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 an organic membrane in which zeolite particles are simply dispersed. The zeolite membrane 12 may contain two or more types of zeolite with different structures and compositions. In Figure 2, the zeolite membrane 12 is drawn with a thick line. In Figure 3, the zeolite membrane 12 is drawn with parallel diagonal lines. In Figure 3, the thickness of the zeolite membrane 12 is drawn thicker than it actually is.

The support 11 is a porous member that is permeable to gas and liquid. In the example shown in FIG. 2, the support 11 is a monolithic support having a single continuous columnar body that is molded as an integral unit and has a plurality of through holes 111 that extend in the longitudinal direction (i.e., the left-right direction in FIG. 2). In the example shown in FIG. 2, the support 11 is approximately cylindrical. The cross section perpendicular to the longitudinal direction of each through hole 111 (i.e., cell) is, for example, approximately circular. In FIG. 2, the diameter of the through holes 111 is larger than the actual diameter, and the number of through holes 111 is smaller than the actual number. The zeolite membrane 12 is formed on the inner surface of the through holes 111 and covers the inner surface of the through holes 111 over almost the entire surface.

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 column shape. When the shape of the support 11 is a tubular or cylindrical shape, the thickness of the support 11 is, for example, 0.1 mm to 10 mm.

Various substances (e.g., ceramics or metals) can be used as the material for the support 11, so 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 for the support 11 include alumina, silica, mullite, zirconia, titania, yttria, silicon nitride, silicon carbide, and the like. In this embodiment, the support 11 includes at least one of alumina, silica, and mullite.

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

The average pore diameter of the support 11 is, for example, 0.01 μm to 70 μm, preferably 0.05 μm to 25 μm. The average pore diameter of the support 11 near the surface where the zeolite membrane 12 is 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 porosimeter, or a nanoperm porosimeter. Regarding the distribution of pore diameters throughout 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 where the zeolite membrane 12 is formed is, for example, 20% to 60%.

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

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 types of substances by utilizing the molecular sieve action. Other substances are less likely to permeate the zeolite membrane 12 than the specific substance. In other words, the amount of the other substance that permeates the zeolite membrane 12 is smaller than the amount of the specific substance that permeates the zeolite membrane 12.

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 the separation performance. Increasing the thickness of the zeolite membrane 12 increases the permeation rate. The surface roughness (Ra) of the zeolite membrane 12 is, for example, 5 μm or less, preferably 2 μm or less, more preferably 1 μm or less, and even more preferably 0.5 μm or less.

The average pore diameter of the zeolite crystals contained in the zeolite membrane 12 (hereinafter also simply referred to as the "average 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 0.5 nm or less, and even more preferably 0.3 nm or more and 0.4 nm or less. The average pore diameter of the zeolite membrane 12 is the arithmetic mean of the maximum diameter of the pores of the zeolite crystals constituting the zeolite membrane 12 (i.e., the long diameter, which is the maximum distance between oxygen atoms) and the diameter of the pores in a direction approximately perpendicular to the long diameter (i.e., the short diameter). The average pore diameter of the zeolite membrane 12 is smaller than the average pore diameter of the support 11 in the vicinity of the surface on which the zeolite membrane 12 is formed.

When the maximum number of rings of the zeolite constituting the zeolite membrane 12 is n, the average pore diameter is the arithmetic average of the short diameter and long diameter of the n-ring pores. When the zeolite has multiple n-ring pores with the same n, the average pore diameter of the zeolite is the arithmetic average of the short diameter and long diameter of all the n-ring pores. Note that the n-ring refers to a portion in which the number of oxygen atoms constituting the skeleton forming the pores is n, and each oxygen atom is bonded to a T atom described below to form a ring structure. In addition, the n-ring refers to a ring that forms a through hole (channel), and does not include a ring that does not form a through hole. The n-ring pore is a pore formed by an n-ring. It is preferable that the maximum number of rings of the zeolite contained in the zeolite membrane 12 is 8 or less (for example, 6 or 8).

The average pore size 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 Society's "Database of Zeolite Structures" [online] on the Internet at URL: http://www.iza-structure.org/databases/.

The zeolite membrane 12 is, for example, a DDR-type zeolite. In other words, the zeolite membrane 12 is a zeolite membrane made of zeolite whose structure code defined by the International Zeolite Society is "DDR." In this case, the inherent pore size of the zeolite that makes up the zeolite membrane 12 is 0.36 nm x 0.44 nm, and the average pore size is 0.40 nm.

The type of zeolite constituting the zeolite membrane 12 is not particularly limited, but may be, for example, AEI type, AEN type, AFN type, AFV type, AFX type, BEA type, CHA type, DDR type, ERI type, ETL type, FAU type (X type, Y type), GIS type, LEV type, LTA type, MEL type, MFI type, MOR type, PAU type, RHO type, SAT type, SOD type, etc. Zeolite is more preferably, for example, AEI type, AFN type, AFV type, AFX type, CHA type, DDR type, ERI type, ETL type, GIS type, LEV type, LTA type, PAU type, RHO type, SAT type, etc. More preferred are zeolites such as AEI type, AFN type, AFV type, AFX type, CHA type, DDR type, ERI type, ETL type, GIS type, LEV type, PAU type, RHO type, and SAT type.

The zeolite constituting the zeolite membrane 12 contains, for example, aluminum (Al) as a T atom (i.e., an atom located at the center of an oxygen tetrahedron ( _TO4 ) constituting the zeolite). As the zeolite constituting the zeolite membrane 12, a zeolite in which the T atom is only silicon (Si) or is composed of Si and Al, an AlPO type zeolite in which the T atom is composed of Al and phosphorus (P), a SAPO type zeolite in which the T atom is composed of Si, Al and P, a MAPSO type zeolite in which the T atom is composed of magnesium (Mg), Si, Al and P, a ZnAPSO type zeolite in which the T atom is composed of zinc (Zn), Si, Al and P, etc. can be used. Some of the T atoms may be substituted with other elements.

The zeolite membrane 12 contains, for example, Si. The zeolite membrane 12 may contain, for example, any two or more of Si, Al, and P. The zeolite membrane 12 may contain an alkali metal. The alkali metal is, for example, sodium (Na) or potassium (K). 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 the molar ratio of Si elements to Al elements contained in the zeolite membrane 12. The Si/Al ratio is preferably 5 or more, more preferably 20 or more, and even more preferably 100 or more, and the higher the ratio, the more preferable 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 _CO2 permeation amount (permeance) of the zeolite membrane 12 at 20°C to 400°C is, for example, 100 nmol/ ^m2 ·s·Pa or more. In addition, the _CO2 permeation amount/ _CH4 leakage amount ratio (permeance ratio) of the zeolite membrane 12 at 20°C to 400°C is, for example, 100 or more. The permeance and permeance ratio are those when the partial pressure difference of _CO2 between the supply side and the permeation side of the zeolite membrane 12 is 1.5 MPa.

Next, an example of the manufacturing flow of the zeolite membrane composite 1 will be described. When the zeolite membrane composite 1 is manufactured, first, seed crystals to be used in manufacturing the zeolite membrane 12 are prepared. The seed crystals are obtained, for example, from DDR-type zeolite powder produced by hydrothermal synthesis. The zeolite powder may be used as the seed crystals as is, or the seed crystals may be obtained by processing the powder by pulverization or the like.

Then, the porous support 11 is immersed in the solution in which the seed crystals are dispersed, and the seed crystals are attached to the support 11. Alternatively, the solution 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 support with attached seed crystals is produced. The seed crystals may be attached to the support 11 by other methods.

The support 11 with the seed crystal attached thereto is immersed in the raw material solution. The raw material solution is prepared by dissolving, 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.

Then, the seed crystals are used as nuclei to grow DDR-type zeolite by hydrothermal synthesis, thereby forming a DDR-type zeolite membrane 12 on the support 11. The temperature during hydrothermal synthesis is preferably 120 to 200°C, for example 160°C. The hydrothermal synthesis time is preferably 10 to 100 hours, for example 30 hours.

When the hydrothermal synthesis is completed, the support 11 and the zeolite membrane 12 are washed with pure water. After washing, the support 11 and the zeolite membrane 12 are dried, for example, at 80°C. After drying the support 11 and the zeolite membrane 12, the zeolite membrane 12 is heat-treated to almost completely burn off the SDA in the zeolite membrane 12 and penetrate the micropores in the zeolite membrane 12. This results in the above-mentioned zeolite membrane composite 1.

The sealing parts 21 of the separation device 2 shown in FIG. 1 are attached to both ends of the support 11 of the zeolite membrane composite 1 in the longitudinal direction (i.e., the left-right direction in FIG. 1) and are members that cover and seal both longitudinal end faces of the support 11 and the outer surfaces near both end faces. The sealing parts 21 prevent gas from flowing in and out from both end faces of the support 11. The sealing parts 21 are, for example, plate-like members made of glass or resin. The material and shape of the sealing parts 21 may be changed as appropriate. Note that the sealing parts 21 have multiple openings that overlap with the multiple through holes 111 of the support 11, so that both longitudinal ends of each through hole 111 of the support 11 are not covered by the sealing parts 21. Therefore, gas and the like can flow in and out of the through holes 111 from both ends.

The shape of the outer cylinder 22 is not limited, but is, for example, a substantially cylindrical tubular member. The outer cylinder 22 is formed, for example, from stainless steel or carbon steel. The longitudinal direction of the outer cylinder 22 is substantially parallel to the longitudinal direction of the zeolite membrane composite 1. A supply port 221 is provided at one end of the outer cylinder 22 in the longitudinal direction (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 outer cylinder 22. A supply unit 26 is connected to the supply port 221. A first recovery unit 27 is connected to the first discharge port 222. The internal space of the outer cylinder 22 is a sealed space isolated from the space around the outer cylinder 22.

In the example shown in FIG. 1, the outer tube 22 includes a tube portion 224, two flange portions 225, and two lid portions 226. The tube portion 224 is a generally cylindrical portion having openings at both longitudinal ends. The two flange portions 225 are generally annular plate-shaped portions that extend radially outward from the tube portion 224 around the two openings of the tube portion 224. The tube portion 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 tube portion 224. As a result, the two openings of the tube portion 224 are hermetically sealed.

The above-mentioned supply port 221 is provided in the lid portion 226 on the left side in FIG. 1. The first discharge port 222 is provided in the lid portion 226 on the right side in FIG. 1. The second discharge port 223 is provided in approximately the center in the longitudinal direction of the tube portion 224. Note that in the outer tube 22, the tube portion 224 may have an opening only at one end in the longitudinal direction. In this case, the flange portion 225 and the lid portion 226 are provided only on that one side in the longitudinal direction.

The two seal members 23 are disposed around the entire circumference between the outer surface of the zeolite membrane composite 1 and the inner surface of the outer tube 22 near both ends of the zeolite membrane composite 1 in the longitudinal direction. Each seal member 23 is an approximately annular member made of a material that is gas impermeable. The seal member 23 is, for example, an O-ring made of a flexible resin. The seal member 23 is in close contact with the outer surface of the zeolite membrane composite 1 and the inner surface of the outer tube 22 around the entire circumference. In the example shown in FIG. 1, the seal member 23 is in close contact with the outer surface of the sealing portion 21 and indirectly in close contact with the outer surface of the zeolite membrane composite 1 via the sealing portion 21. The gap between the seal member 23 and the outer surface of the zeolite membrane composite 1 and the gap between the seal member 23 and the inner surface of the outer tube 22 are sealed, and gas is hardly or completely unable to pass through.

The shape of the outer casing 24 is not limited, but for example, it is a substantially cylindrical member with both ends in the longitudinal direction closed. The outer casing 24 is formed of, for example, stainless steel or carbon steel. The longitudinal direction of the outer casing 24 is substantially parallel to the longitudinal direction of the zeolite membrane composite 1 and the outer tube 22. The internal space of the outer casing 24 is a sealed space isolated from the space around the outer casing 24. In the internal space of the outer casing 24, the outer tube 22 is supported at a distance from the inner surface of the outer casing 24 by a support member not shown in the figure or the like. The outer tube 22 is disposed approximately at the center in the radial direction and approximately at the center in the longitudinal direction in the internal space of the outer casing 24. Therefore, inside the outer casing 24, a space 240 (hereinafter also referred to as the "outer space 240") is formed between the outer casing 24 and the outer tube 22. Between the inner surface of the outer casing 24 and the outer surface of the tube portion 224 of the outer tube 22, the radial width of the outer space 240 is substantially uniform over the entire circumference in the circumferential direction.

1, the entire outer tube 22 is accommodated inside the exterior body 24, but a part of the outer tube 22 may be exposed to the outside from the exterior body 24. In other words, the outer tube 22 may be partially accommodated inside the exterior body 24. For example, the entire tubular portion 224 of the outer tube 22 may be accommodated inside the exterior body 24, and the portion of the outer tube 22 other than the tubular portion 224 may be exposed to the outside from the exterior body 24. In this case, the exterior space 240 exists at least in the normal direction of the outer surface of the tubular portion 224. In other words, the exterior space 240 exists at least in the normal direction of the main surface of the zeolite membrane 12 of the zeolite membrane composite 1 (i.e., at least in the normal direction of the inner surface of the through hole 111 of the support 11).

The supply port 221 of the outer tube 22 is connected to the supply unit 26 via a pipe that airtightly penetrates the outer body 24. The first exhaust port 222 of the outer tube 22 is connected to the first recovery unit 27 via a pipe that airtightly penetrates the outer body 24. The second exhaust port 223 of the outer tube 22 opens toward the internal space of the outer body 24. The gas guided to the second exhaust port 223 in the outer tube 22 is exhausted from the second exhaust port 223 to the outer space 240. That is, in the example shown in FIG. 1, the second exhaust port 223 is an introduction port that can introduce gas into the outer space 240. The gas in the outer space 240 is exhausted to the outside of the outer body 24 via the outer body exhaust port 241 provided at the end of the outer body 24 in the longitudinal direction (for example, the end on the left side in FIG. 1). The second recovery unit 28 is connected to the outer body exhaust port 241.

The second exhaust port 223 of the outer tube 22 may be connected to the second collection section 28 via a pipe that extends in the internal space of the exterior body 24 and airtightly penetrates the exterior body 24. In this case, the destination of the gas from the second exhaust port 223 is switched by a valve or the like, so that the second exhaust port 223 is switched between a state in which it is connected to the second collection section 28 via the above-mentioned pipe and a state in which it functions as an introduction port that opens toward the internal space of the exterior body 24. In this case, the exterior body exhaust port 241 may or may not be connected to the second collection section 28. When the second exhaust port 223 is connected to the second collection section 28 via the above-mentioned pipe, the gas exhausted from the second exhaust port 223 is exhausted to the outside of the exterior body 24 without being supplied to the exterior space 240. That is, the gas discharged from the second exhaust port 223 of the outer cylinder 22 can be introduced into the exterior space 240 via the second exhaust port 223 (i.e., the introduction port), but it can also be in a state where it is not introduced into the exterior space 240.

In addition, a portion of the gas discharged from the second exhaust port 223 may be introduced into the exterior space 240 via the second exhaust port 223, and the remainder may be discharged from the exterior body 24 without being introduced into the exterior space 240. The number of exterior body exhaust ports 241 provided in the exterior body 24 may be one or two or more. Each exterior body exhaust port 241 may be opened or closed as necessary. When multiple exterior body exhaust ports 241 are provided in the exterior body 24, the gas introduced into the exterior space 240 may be discharged to the outside of the exterior body 24 from one or more exterior body exhaust ports 241.

In the separation device 2, at least a portion of the zeolite membrane composite 1 is contained in a space 243 indicated by parallel diagonal lines in FIG. 4. The space 243 is a space surrounded by the exterior body 24, an inlet port (in the example shown in FIG. 4, the second outlet port 223), and the exterior body outlet port 241, and is hereinafter also referred to as the "inter-port space 243." In the separation device 2, the inlet port and the exterior body outlet port 241 are arranged so that at least a portion of the zeolite membrane composite 1 is contained in the inter-port space 243. Preferably, the inter-port space 243 contains 50% or more by volume of the zeolite membrane composite 1.

Here, the inter-port space 243 is the internal space of the exterior body 24, and is the space sandwiched between the inlet port plane 244 and the exterior body discharge port plane 245. The inlet port plane 244 is a plane that is perpendicular to a line 246 that connects the approximate center of the inlet port of the outer tube 22 and the approximate center of the exterior body discharge port 241, and passes through the approximate center of the inlet port. The exterior body discharge port plane 245 is a plane that is perpendicular to the line 246 and passes through the approximate center of the exterior body discharge port 241. In other words, the inter-port space 243 is the space between the inlet port plane 244 and the exterior body discharge port plane 245, which are parallel, and is a space that is included inside the exterior body 24.

In the separation device 2, when a single exterior body 24 has multiple exterior body discharge ports 241 and/or multiple introduction ports provided therein, the above-mentioned inter-port space 243 is a collection of all inter-port spaces corresponding to all combinations of the exterior body discharge ports 241 and introduction ports. In other words, the above-mentioned inter-port space 243 includes all inter-port spaces obtained in combinations of one exterior body 24 and any of the exterior body discharge ports 241 and introduction ports provided therein. Note that when calculating the volume of the inter-port space 243, the overlapping portions of the inter-port spaces in the collection of all the inter-port spaces are not counted as a duplicate volume.

The supply unit 26 supplies the mixed gas to the internal space of the outer tube 22 via the supply port 221. The supply unit 26 includes, for example, a blower or pump that pressure-feeds the mixed gas toward the outer tube 22. The blower or pump includes a pressure adjustment unit that adjusts the pressure of the mixed gas supplied to the outer tube 22. The supply unit 26 is provided with a heating unit 261 that heats the mixed gas before it is supplied to the outer tube 22. The heating unit 261 includes, for example, an electric heater. The first collection unit 27 includes, for example, a storage container that stores the gas derived from the outer tube 22, or a blower or pump that transfers the gas. The second collection unit 28 includes, for example, a storage container that stores the gas derived from the exterior body 24, or a blower or pump that transfers the gas.

Next, an example of the flow of separation of mixed gas by the separation device 2 (i.e., an operating method of the separation device 2) will be described with reference to Fig. 5. When separation of mixed gas is performed, the above-mentioned separation device 2 is first prepared, and the zeolite membrane composite 1 is prepared. Next, the supply unit 26 supplies a mixed gas containing a plurality of types of gases having different permeabilities to the zeolite membrane 12 to the internal space of the outer cylinder 22 (step S11). For example, the main components of the mixed gas are _CO2 and _CH4 . The mixed gas may contain gases other than _CO2 and _CH4 .

The pressure of the mixed gas supplied from the supply unit 26 to the internal space of the outer cylinder 22 (i.e., the introduction pressure) is, for example, 0.1 MPa to 20.0 MPa. The temperature of the mixed gas supplied from the supply unit 26 is higher than the temperature around the exterior body 24 (i.e., the temperature outside the exterior body 24). The temperature of the mixed gas supplied from the supply unit 26 is, for example, 30°C to 250°C, preferably 50°C to 250°C, and more preferably 70°C to 200°C. The mixed gas may be heated by the heating unit 261 to a temperature higher than the temperature around the exterior body 24, or may originally be higher than the temperature around the exterior body 24.

The mixed gas supplied from the supply unit 26 to the outer cylinder 22 is introduced into each through-hole 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 high permeability in the mixed gas (e.g., _CO2 , hereinafter referred to as a "highly permeable substance") permeates through the zeolite membrane 12 provided on the inner surface of each through-hole 111 and the support 11, and is discharged from the outer surface of the support 11. As a result, the highly permeable substance is separated from a gas having low permeability in the mixed gas (e.g., _CH4 , hereinafter referred to as a "lowly permeable substance") (step S12).

The gas (hereinafter referred to as "permeating substance") that has permeated the zeolite membrane composite 1 and is discharged from the outer surface of the support 11 is led from the outer tube 22 to the exterior space 240 through the second discharge port 223, as shown by the arrow 253 (step S13). The permeating substance introduced from the outer tube 22 to the exterior space 240 diffuses throughout almost the entire exterior space 240 and flows toward the exterior body discharge port 241 while directly contacting the outer surface of the outer tube 22 and the inner surface of the exterior body 24. In the separation device 2, the exterior space 240 is filled with a permeating substance that is hotter than the temperature around the exterior body 24, thereby suppressing a decrease in the temperature of the exterior tube 22 due to heat radiation to the outside. The permeating substance flowing through the exterior space 240 is discharged from the exterior space 240 to the outside of the exterior body 24 through the exterior body discharge port 241, as shown by the arrow 254, and is collected by the second recovery section 28 (step S14). The pressure of the gas recovered by the second recovery section 28 (i.e., the permeation pressure) is, for example, about 1 atmosphere (0.101 MPa).

In the example shown in FIG. 1, the discharge direction 253 of the permeable substance discharged from the second discharge port 223 to the outside of the outer cylinder 22 (i.e., the introduction direction 253 of the permeable substance into the exterior space 240) is a direction approximately parallel to the normal direction of the outer surface of the outer cylinder 22 (i.e., the radial direction perpendicular to the longitudinal direction described above). In addition, the discharge direction 254 of the permeable substance discharged from the exterior body discharge port 241 to the outside of the exterior body 24 is a direction approximately parallel to the longitudinal direction described above. Therefore, the angle between the introduction direction 253 of the permeable substance into the exterior space 240 and the discharge direction 254 from the exterior space 240 is approximately 90 degrees. In the separation device 2, the angle may be changed appropriately within a range of 0 degrees or more and 180 degrees or less.

In addition, gases other than the gas that has permeated the zeolite membrane composite 1 (hereinafter referred to as "non-permeable substances") in the mixed gas pass through each through-hole 111 of the support 11 from left to right in FIG. 1. As shown by arrow 252, the non-permeable substances are discharged to the outside of the outer tube 22 and the exterior body 24 via the first discharge port 222 and are recovered by the first recovery section 27. The pressure of the gas recovered by the first recovery section 27 via the first discharge port 222 is, for example, approximately the same as the introduction pressure. In addition to the low-permeability substances described above, the non-permeable substances may also include highly permeable substances that did not permeate the zeolite membrane 12.

Next, a separation device according to a second embodiment of the present invention will be described. FIG. 6 is a diagram showing the schematic structure of a separation device 2a according to a second embodiment of the present invention. In the separation device 2a, the connection between the first discharge port 222 of the outer cylinder 22 and the first recovery section 27, and the connection between the second discharge port 223 and the second recovery section 28 are different from those shown in FIG. 1. The other configurations of the separation device 2a are substantially similar to those of the separation device 2 shown in FIG. 1, and in the following description, the same reference numerals are used to designate the configurations of the separation device 2a that correspond to those of the separation device 2.

As shown in FIG. 6, in the separation device 2a, the second discharge port 223 of the outer cylinder 22 is not open toward the exterior space 240, and is connected to the second recovery section 28 disposed outside the exterior body 24 via a pipe that airtightly penetrates the exterior body 24. Therefore, the permeated material discharged from the second discharge port 223 is recovered by the second recovery section 28 without being introduced into the exterior space 240.

On the other hand, the first discharge port 222 of the outer tube 22 is open toward the exterior space 240. In addition, the first recovery section 27 is connected to the exterior body discharge port 241. The impermeable material discharged from the first discharge port 222 to the exterior space 240 flows inside the exterior space 240 toward the exterior body discharge port 241. That is, in the example shown in FIG. 6, the first discharge port 222 is an introduction port capable of introducing gas into the exterior space 240. The impermeable material is discharged to the outside of the exterior body 24 through the exterior body discharge port 241 and is recovered by the first recovery section 27.

The first exhaust port 222 of the outer tube 22 may be connected to the first collection section 27 via a pipe that extends in the internal space of the exterior body 24 and airtightly penetrates the exterior body 24. In this case, the destination of the gas from the first exhaust port 222 is switched by a valve or the like, so that the first exhaust port 222 is switched between a state in which it is connected to the first collection section 27 via the above-mentioned pipe and a state in which it functions as an introduction port that opens toward the internal space of the exterior body 24. In this case, the exterior body exhaust port 241 may or may not be connected to the first collection section 27. When the first exhaust port 222 is connected to the first collection section 27 via the above-mentioned pipe, the gas exhausted from the first exhaust port 222 is exhausted to the outside of the exterior body 24 without being supplied to the exterior space 240. That is, the gas discharged from the first exhaust port 222 of the outer cylinder 22 can be introduced into the exterior space 240 through the first exhaust port 222 (i.e., the introduction port), but it can also be in a state where it is not introduced into the exterior space 240.

In addition, a portion of the gas discharged from the first exhaust port 222 may be introduced into the exterior space 240 via the first exhaust port 222, and the remainder may be discharged from the exterior body 24 without being introduced into the exterior space 240. As described above, the number of exterior body exhaust ports 241 provided in the exterior body 24 may be one or two or more. Each exterior body exhaust port 241 may be opened or closed as necessary. When multiple exterior body exhaust ports 241 are provided in the exterior body 24, the gas introduced into the exterior space 240 may be discharged to the outside of the exterior body 24 from one or more exterior body exhaust ports 241.

In the separation device 2a, at least a part of the zeolite membrane composite 1 is included in the inter-port space 243a shown with parallel diagonal lines in FIG. 7. As described above, the inter-port space 243a is a space surrounded by the outer casing 24, the inlet port (the first discharge port 222 in the example shown in FIG. 7), and the outer casing discharge port 241. In other words, the inter-port space 243a is an internal space of the outer casing 24, and is a space sandwiched between the inlet port plane 244a (a plane perpendicular to the straight line 246a connecting the approximate center of the inlet port of the outer casing 22 and the approximate center of the outer casing discharge port 241, and passing through the approximate center of the inlet port) and the outer casing discharge port plane 245a (a plane perpendicular to the straight line 246a connecting the approximate center of the inlet port of the outer casing 22 and the approximate center of the outer casing discharge port 241, and passing through the approximate center of the outer casing discharge port 241). In the separation device 2a, the inlet port and the exterior body discharge port 241 are arranged so that at least a portion of the zeolite membrane composite 1 is contained in the inter-port space 243a. Preferably, 50% or more by volume of the zeolite membrane composite 1 is contained in the inter-port space 243a.

The flow of mixed gas separation by the separator 2a is substantially the same as the flow of mixed gas separation by the separator 2, except that steps S23 to S24 shown in FIG. 8 are performed instead of steps S13 to S14 in FIG. 5. In the separator 2a, first, mixed gas having a higher temperature than the temperature around the exterior body 24 is supplied by the supply unit 26 to the internal space of the outer cylinder 22 (FIG. 5: step S11).

The mixed gas supplied to the outer cylinder 22 is introduced into each through-hole 111 of the support 11, as shown by arrows 251. Highly permeable substances in the mixed gas permeate through the zeolite membrane 12 provided on the inner surface of each through-hole 111 and the support 11, and are discharged from the outer surface of the support 11. This separates the highly permeable substances from the less permeable substances (FIG. 5: step S12).

The permeated material that has permeated the zeolite membrane composite 1 is discharged to the outside of the outer tube 22 and the outer casing 24 via the second discharge port 223, as shown by the arrow 253, and is collected by the second collection section 28. The pressure of the gas collected by the second collection section 28 (i.e., the permeation pressure) is, for example, about 1 atmosphere (0.101 MPa).

On the other hand, the impermeable substances other than the permeable substances in the mixed gas pass through each through hole 111 of the support 11 and are led from the outer tube 22 to the exterior space 240 through the first discharge port 222 as shown by the arrow 252 (FIG. 8: step S23). The impermeable substances introduced from the outer tube 22 to the exterior space 240 diffuse throughout almost the entire exterior space 240 and flow toward the exterior body discharge port 241 while directly contacting the outer surface of the outer tube 22 and the inner surface of the exterior body 24. In the separation device 2a, the exterior space 240 is filled with an impermeable substance having a higher temperature than the ambient temperature of the exterior body 24, thereby suppressing the temperature drop of the exterior tube 22 due to heat radiation to the outside. The impermeable substances flowing through the exterior space 240 are discharged from the exterior space 240 to the outside of the exterior body 24 through the exterior body discharge port 241 as shown by the arrow 254, and are collected by the first collection section 27 (FIG. 8: step S24). The pressure of the gas recovered by the first recovery section 27 is, for example, approximately the same as the introduction pressure. In addition to the low-permeability substances described above, the impermeable substances may also include highly permeable substances that did not permeate the zeolite membrane 12.

6, the discharge direction 252 of the impermeable material discharged from the first discharge port 222 to the outside of the outer cylinder 22 (i.e., the introduction direction 252 of the impermeable material into the exterior space 240) is approximately parallel to the longitudinal direction and is a direction toward the right in FIG. 6. Also, the discharge direction 254 of the impermeable material discharged from the exterior body discharge port 241 to the outside of the exterior body 24 is approximately parallel to the longitudinal direction and is a direction toward the left in FIG. 6. Therefore, the angle between the introduction direction 252 of the impermeable material into the exterior space 240 and the discharge direction 254 from the exterior space 240 is approximately 180 degrees. In the separation device 2a, the angle may be changed as appropriate within a range of 0 degrees or more and 180 degrees or less.

As described above, the separation device 2, 2a includes a separation membrane composite (i.e., zeolite membrane composite 1), an outer tube 22, an exterior body 24, and a supply unit 26. The zeolite membrane composite 1 includes a porous support 11 and a separation membrane (i.e., zeolite membrane 12) formed on the support 11. The outer tube 22 accommodates the zeolite membrane composite 1 inside. The exterior body 24 accommodates the outer tube 22 inside. The supply unit 26 supplies a fluid to the inside of the outer tube 22. The fluid is at a higher temperature than the temperature around the exterior body 24. The outer tube 22 includes a first discharge port 222 and a second discharge port 223. The first discharge port 222 discharges non-permeable substances, which are substances other than the permeable substances that have permeated the zeolite membrane composite 1, from the fluid to the outside of the outer tube 22. The second discharge port 223 discharges permeable substances from the fluid to the outside of the outer tube 22.

One of the permeable substance and the non-permeable substance discharged from the outer tube 22 can be introduced into the outer tube space 240, which is the space between the outer tube 24 and the outer tube 22 inside the outer tube 24, through an introduction port (i.e., the second discharge port 223 or the first discharge port 222). In this way, in the separation device 2, 2a, the one of the substances, which is higher than the temperature around the outer tube 24, flows through the outer tube space 240, thereby suppressing the temperature drop of the outer tube 22 due to heat radiation to the surroundings. This makes it possible to suppress the temperature drop of the fluid, the permeable substance, and the non-permeable substance inside the outer tube 22. As a result, it is possible to reduce the energy required for separating the fluid at high temperatures. Note that the one of the substances is a permeable substance in the separation device 2 and a non-permeable substance in the separation device 2a. Since the temperature drop of the outer tube 22 can be further suppressed, it is preferable that the pressure of the substance flowing through the outer tube space 240 is atmospheric pressure or higher. In addition, since the structure of the outer tube 24 can be made simpler and less expensive, it is preferable that the pressure of the substance flowing through the outer tube space 240 is 10 atmospheres or less.

As described above, in the separation device 2, 2a, the exterior body 24 is provided with an exterior body discharge port 241 capable of discharging the one substance introduced into the exterior space 240 by the introduction port. In addition, at least a part of the zeolite membrane composite 1 is contained in the space surrounded by the exterior body 24, the introduction port, and the exterior body discharge port 241 (i.e., the inter-port space 243, 243a). As a result, the one substance introduced from the outer tube 22 into the exterior space 240 through the introduction port and heading toward the outside of the exterior body 24 does not flow in one direction for a short distance in the exterior space 240, but flows for a relatively long distance in a relatively complicated path surrounding the outer tube 22. As a result, heat radiation from the outer tube 22 to the surroundings can be further suppressed. Therefore, the energy required for fluid separation at high temperatures can be further reduced.

As described above, it is preferable that the exterior space 240 exists at least in the normal direction of the main surface of the zeolite membrane 12. This allows the outer surface of the outer tube 22 to be covered by the exterior space 240, making it possible to efficiently suppress heat dissipation from the outer tube 22 to the surroundings.

As described above, the outer cylinder 22 preferably includes a cylinder portion 224, a flange portion 225, and a lid portion 226. The cylinder portion 224 has an opening at at least one end. The flange portion 225 extends outward from the cylinder portion 224 around the opening. The lid portion 226 seals the opening by being fixed to the flange portion 225 while covering the opening. In an outer cylinder 22 having this structure, there is a possibility that the temperature drop of the outer cylinder 22 will be relatively large due to heat dissipation from the flange portion 225. Therefore, the separation device 2, 2a that can suppress the temperature drop of the outer cylinder 22 is particularly suitable for a separation device that includes an outer cylinder 22 having the above structure.

As described above, it is preferable that the space surrounded by the outer casing 24, the inlet port, and the outer casing outlet port 241 (i.e., the inter-port space 243, 243a) contains 50% or more by volume of the zeolite membrane composite 1. This makes it possible to further suppress heat dissipation from the outer casing 22 to the surroundings, and further reduce the energy required for fluid separation at high temperatures.

As described above, in the separation device 2, one of the substances is a permeable substance. In this way, by introducing a permeable substance, which is at a lower pressure than the impermeable substance, into the exterior space 240, the structure of the exterior body 24 can be simplified (e.g., made smaller and/or lighter).

As described above, it is preferable that the separation device 2, 2a further includes a heating section 261 that heats the fluid before it is supplied to the outer cylinder 22. This makes it possible to easily achieve separation of the fluid at high temperatures in the separation device 2, 2a, even if the fluid is at a low temperature before it is supplied to the separation device 2, 2a. Note that various types of heating section 261 can be used, such as an electric heater, a heat exchanger, or a heat pump.

As described above, the temperature of the fluid supplied by the supply unit 26 is preferably 70°C or higher. As described above, the separation device 2, 2a can suppress a decrease in temperature of the outer cylinder 22, so the structure of the separation device 2, 2a is particularly suitable when the temperature of the fluid supplied from the supply unit 26 is relatively high (i.e., when there is a large temperature difference between the fluid and the surroundings of the exterior body 24).

As described above, the separation membrane of the separation membrane composite is preferably a zeolite membrane 12. In this way, by using a zeolite membrane 12 having a specific pore size as the separation membrane, selective permeation of the target substance through the separation membrane can be suitably achieved, and the target substance can be efficiently separated from the fluid.

In addition, the maximum number of ring members of the zeolite constituting the zeolite membrane 12 is preferably 8 or less. This allows the selective permeation of the target substances such as _H2 and _CO2 , which have relatively small molecular diameters, to be suitably realized, and the target substances to be permeated can be efficiently separated from the fluid.

As described above, the method of operating the separation device 2, 2a includes the steps of: supplying a fluid having a higher temperature than the temperature around the exterior body 24 to the inside of the outer casing 22 (step S11); introducing one of the permeating substances that have permeated the separation membrane composite (i.e., the zeolite membrane composite 1) in the fluid and the non-permeating substances that are substances other than the permeating substances in the fluid into the exterior space 240, which is the space between the exterior body 24 and the exterior casing 22 inside the exterior body 24 (steps S13, S23); and discharging the one of the substances from the exterior space 240 by passing through at least a part of the exterior space 240 that exists in the normal direction of the main surface of the separation membrane (i.e., the zeolite membrane 12) (steps S14, S24). As a result, as described above, it is possible to suppress the temperature drop of the exterior casing 22 due to heat radiation to the surroundings, and as a result, it is possible to reduce the energy required for separation of the fluid at high temperatures.

In the separation device 2 shown in FIG. 1, a partition plate may be provided in the space between the outer surface of the outer tube 22 and the inner surface of the exterior body 24 in the exterior space 240, and a flow path may be formed that extends in a spiral shape around the outer tube 22 in the longitudinal direction. The flow path connects the space on the right side of the outer tube 22 with the space on the left side. The relatively high-temperature permeable material discharged from the second discharge port 223 flows through the flow path and directly contacts almost the entire outer surface of the outer tube 22. This makes it possible to suppress heat dissipation from the outer tube 22 to the surroundings, thereby reducing the energy required for separating fluids at high temperatures. Note that the above-mentioned flow path does not necessarily have to be spiral. For example, a labyrinth-shaped (so-called zigzag-shaped) flow path may be formed by alternately arranging partition plates that extend radially outward from the outer surface of the outer tube 22 and partition plates that extend radially inward from the inner surface of the exterior body 24 in the longitudinal direction. The same applies to the separation device 2a.

In the above-mentioned separation device 2, as shown in FIG. 9, a heat insulating section 242 may be provided around the exterior body 24 to insulate at least a part of the outer surface of the exterior body 24. This can suppress heat radiation from the exterior body 24 to the surroundings, and therefore the energy required for fluid separation by the zeolite membrane composite 1 at high temperatures can be further reduced. It is more preferable that the heat insulating section 242 insulates almost the entire outer surface of the exterior body 24. This can further suppress heat radiation from the exterior body 24 to the surroundings. The same is true for the separation device 2a shown in FIG. 6. The heat insulating section 242 is, for example, a heat insulating material such as glass wool or cellulose fiber that covers the outer surface of the exterior body 24. The heat insulating section 242 may also be another exterior body arranged around the exterior body 24. Various materials other than the heat insulating material can be used as the heat insulating section 242.

Figure 10 is a diagram showing the schematic structure of another preferred separation device 2b. In the separation device 2b, two outer cylinders 22 are housed inside the exterior body 24. The internal structure of the two outer cylinders 22 is approximately the same as that of the above-mentioned outer cylinders 22. In the left outer cylinder 22 in Figure 10, the supply port 221 is connected to the supply section 26, and the second discharge port 223 opens toward the exterior space 240. The first discharge port 222 of the left outer cylinder 22 in Figure 10 is connected to the supply port 221 of the right outer cylinder 22. The non-permeable material discharged from the first discharge port 222 is supplied to the right outer cylinder 22, and separation of the highly permeable material is performed again in the right outer cylinder 22. The first discharge port 222 of the right outer cylinder 22 is connected to the first recovery section 27, and the second discharge port 223 opens toward the exterior space 240. That is, in the example shown in Figure 10, the two second discharge ports 223 are introduction ports that can introduce gas into the exterior space 240.

The relatively high-temperature (i.e., higher than the temperature around the exterior body 24) permeable material introduced from the two exterior cylinders 22 into the exterior space 240 flows through the exterior space 240 while directly contacting the outer surfaces of the two exterior cylinders 22 and the inner surface of the exterior body 24, and is discharged to the outside of the exterior body 24 via the exterior body discharge port 241 and collected by the second collection section 28. This makes it possible to suppress the temperature drop of the two exterior cylinders 22 due to heat dissipation to the surroundings, and as a result, it is possible to reduce the energy required for fluid separation at high temperatures.

Each second exhaust port 223 may be connected to the second collection section 28 via a pipe that extends in the internal space of the exterior body 24 and airtightly penetrates the exterior body 24. In this case, the destination of the gas from each second exhaust port 223 is switched by a valve or the like, so that each second exhaust port 223 is switched between a state in which it is connected to the second collection section 28 via the above-mentioned pipe and a state in which it functions as an introduction port that opens toward the internal space of the exterior body 24.

The inter-port space 243b of the separation device 2b contains at least a part of the zeolite membrane composite 1 in the two outer cylinders 22. This further suppresses heat radiation from the outer cylinder 22 to the surroundings as described above, and as a result, the energy required for fluid separation at high temperatures can be further reduced. Preferably, the inter-port space 243b contains 50% or more by volume of the zeolite membrane composite 1 (i.e., the volume of one zeolite membrane composite 1 or more). This further reduces the energy required for fluid separation at high temperatures. Note that in the separation device 2b, three or more outer cylinders 22 may be housed inside the exterior body 24.

Figure 11 is a diagram showing the schematic structure of another preferred separation device 2c. In the separation device 2c, two external cylinders 22 are housed inside the exterior body 24, similar to the separation device 2b shown in Figure 10. The internal structure of the two external cylinders 22 is approximately the same as that of the above-mentioned external cylinders 22. In the external cylinder 22 on the left side in Figure 11, the supply port 221 is connected to the supply section 26, and the second discharge port 223 is connected to the second recovery section 28. The first discharge port 222 of the external cylinder 22 on the left side in Figure 11 is connected to the supply port 221 of the external cylinder 22 on the right side. The non-permeable material discharged from the first discharge port 222 is supplied to the external cylinder 22 on the right side, and separation of the highly permeable material is performed again in the external cylinder 22 on the right side. The first discharge port 222 of the external cylinder 22 on the right side opens toward the exterior space 240, and the second discharge port 223 is connected to the second recovery section 28. That is, in the example shown in FIG. 11, the first exhaust port 222 of the right-side outer cylinder 22 is an introduction port that can introduce gas into the exterior space 240.

The relatively high-temperature (i.e., higher than the temperature around the exterior body 24) impermeable material that passes through the two exterior cylinders 22 and is introduced into the exterior space 240 from the first discharge port 222 of the right exterior cylinder 22 flows through the exterior space 240 while directly contacting the outer surfaces of the two exterior cylinders 22 and the inner surface of the exterior body 24, and is discharged to the outside of the exterior body 24 via the exterior body discharge port 241 and collected by the first collection section 27. This makes it possible to suppress the temperature drop of the two exterior cylinders 22 due to heat dissipation to the surroundings, and as a result, it is possible to reduce the energy required to separate the fluid at high temperatures.

The first exhaust port 222 of the right-side outer tube 22 may be connected to the first recovery section 27 via a pipe that extends in the internal space of the outer tube 24 and airtightly penetrates the outer tube 24. In this case, the destination of the gas from the first exhaust port 222 of the right-side outer tube 22 is switched by a valve or the like, so that the first exhaust port 222 is switched between a state in which it is connected to the first recovery section 27 via the above-mentioned pipe and a state in which it functions as an introduction port that opens toward the internal space of the outer tube 24.

The inter-port space 243c of the separation device 2c contains at least a portion of the zeolite membrane composite 1 in the two outer cylinders 22. This further suppresses heat radiation from the outer cylinder 22 to the surroundings as described above, and as a result, the energy required for fluid separation at high temperatures can be further reduced. Preferably, the inter-port space 243c contains 50% or more by volume of the zeolite membrane composite 1 (i.e., the volume of one zeolite membrane composite 1 or more). This further reduces the energy required for fluid separation at high temperatures. Note that in the separation device 2c, three or more outer cylinders 22 may be housed inside the exterior body 24.

Figure 12 is a diagram showing a schematic structure of another preferred separation device 2d. In the separation device 2d, a cylindrical zeolite membrane composite 1d is accommodated inside an outer cylinder 22d. The zeolite membrane composite 1d includes a substantially cylindrical support 11d and a zeolite membrane 12d formed on the outer surface of the support 11d. In the zeolite membrane composite 1d, the left end in Figure 12 is covered with a sealing portion 21d, and gas cannot flow in or out, including the inner flow path 111d of the support 11d (hereinafter also referred to as the "internal flow path 111d"). On the other hand, at the right end in Figure 12, only the end face of the support 11d is covered with a sealing portion 21d, and the internal flow path 111d is open. Therefore, the gas in the inner flow path can flow out of the zeolite membrane composite 1d from the opening. The seal member 23d is disposed between the outer surface of the zeolite membrane composite 1d and the inner surface of the outer cylinder 22d, near the right end of the zeolite membrane composite 1d in FIG. 12.

A supply port 221d is provided at the left end of the outer tube 22d in FIG. 12, and a second exhaust port 223d is provided at the right end. A first exhaust port 222d is provided on the outer surface of the outer tube 22d. The outer tube 22d is housed inside the exterior body 24. The supply port 221d is connected to the supply section 26 by a pipe that penetrates the exterior body 24. The first exhaust port 222d is connected to the first recovery section 27 by a pipe that penetrates the exterior body 24. The second exhaust port 223d opens toward the exterior space 240 between the exterior body 24 and the outer tube 22d. That is, in the example shown in FIG. 12, the second exhaust port 223d is an introduction port that can introduce gas into the exterior space 240.

The permeated material that has permeated the zeolite membrane composite 1d flows through the internal flow path 111d of the support 11d, and is guided from the outer tube 22d to the exterior space 240 via the second discharge port 223d, as shown by arrow 253. The permeated material introduced from the outer tube 22d to the exterior space 240 diffuses throughout almost the entire exterior space 240, and flows toward the exterior body discharge port 241 while directly contacting the outer surface of the outer tube 22d and the inner surface of the exterior body 24. The permeated material flowing through the exterior space 240 is discharged from the exterior space 240 to the outside of the exterior body 24 via the exterior body discharge port 241, as shown by arrow 254, and is collected by the second collection section 28.

The second exhaust port 223d may be connected to the second recovery section 28 via a pipe that extends in the internal space of the exterior body 24 and airtightly penetrates the exterior body 24. In this case, the destination of the gas from the second exhaust port 223d is switched by a valve or the like, so that the second exhaust port 223d is switched between a state in which it is connected to the second recovery section 28 via the above-mentioned pipe and a state in which it functions as an introduction port that opens toward the internal space of the exterior body 24.

In the example shown in FIG. 12, the second exhaust port 223d (i.e., the introduction port) that exhausts gas to the outside of the outer tube 22d is located on the right side of the exterior body 24 in FIG. 12, and the exhaust direction 253 of the permeating substance (i.e., the introduction direction 253 of the permeating substance into the exterior space 240) is approximately parallel to the longitudinal direction and is a direction toward the right in FIG. 12. Also, the exterior body exhaust port 241 that exhausts gas to the outside of the exterior body 24 is located on the left side of the exterior body 24 in FIG. 12, and the exhaust direction 254 of the permeating substance is approximately parallel to the longitudinal direction and is a direction toward the left in FIG. 12. Therefore, the inter-port space 243d surrounded by the exterior body 24 of the separation device 2d, the second exhaust port 223d, and the exterior body exhaust port 241 includes the entire zeolite membrane composite 1d. Note that the inter-port space 243d only needs to include at least a part of the zeolite membrane composite 1d. As a result, in the separation device 2d, the energy required for fluid separation at high temperatures can be reduced, as described above. Preferably, the inter-port space 243d contains 50% or more by volume of the zeolite membrane composite 1d. This allows the energy required for fluid separation at high temperatures to be further reduced.

In the separation device 2d, the first discharge port 222d of the outer cylinder 22d may open toward the outer space 240, and the second discharge port 223d may be connected to the second recovery section 28 via a pipe that airtightly penetrates the outer body 24. In this case, the outer body discharge port 241 is connected to the first recovery section 27. In this case, too, since at least a portion of the zeolite membrane composite 1d is included in the inter-port space, as described above, the energy required for separating fluids at high temperatures can be reduced. In addition, in the separation device 2d, two or more outer cylinders 22d may be housed inside the outer body 24, approximately similar to the separation devices 2b and 2c.

Various modifications are possible to the above-mentioned separation devices 2, 2a to 2d and the operating methods of the above-mentioned separation devices.

For example, the temperature of the fluid supplied by the supply unit 26 may be less than 70°C as long as it is higher than the temperature around the exterior body 24. Also, the heating unit 261 that heats the fluid may be omitted.

The shape of the outer tube 22 may be modified in various ways; for example, the flange portion 225 may not be provided. The same applies to the outer tube 22d.

The outer cylinder 22 may house multiple zeolite membrane composites 1 inside. In this case, the inter-port space 243 may contain a portion of any one of the multiple zeolite membrane composites 1. The same applies to the outer cylinder 22d.

The exterior body 24 may be surrounded by another exterior body. Also, the exterior body 24 may house multiple exterior bodies therein.

In the separation device 2, as long as the exterior body 24 contains at least a portion of the outer cylinder 22 inside, the exterior space 240 does not necessarily have to exist in the normal direction of the zeolite membrane 12. The same is true for the separation devices 2a to 2d.

The maximum number of rings in the zeolite constituting the zeolite membrane 12 may be greater than 8.

In the separation device 2, instead of the zeolite membrane 12, an inorganic membrane made of an inorganic material other than zeolite, or a membrane other than an inorganic membrane, may be formed on the support 11 as a separation membrane. The same applies to the separation devices 2a to 2d.

In the separation devices 2, 2a to 2d, substances other than those exemplified in the above description may be separated from the fluid.

The separation devices 2, 2a to 2d may be used for the purpose of passing high-temperature highly permeable substances through the zeolite membrane composite 1, rather than for the purpose of separating the resulting highly permeable and low-permeable substances.

The fluid supplied to the separation devices 2, 2a to 2d does not have to be a mixture containing multiple types of gas or liquid.

The configurations in the above embodiment and each modified example may be combined as appropriate as long as they are not mutually inconsistent.

The separation device and its operating method of the present invention can be used to separate a variety of fluids.

Reference Signs List 1, 1d Zeolite membrane composite 2, 2a to 2d Separation device 11, 11d Support 12, 12d Zeolite membrane 22, 22d Outer cylinder 24 Exterior body 26 Supply section 221, 221d Supply port 222, 222d First discharge port 223, 223d Second discharge port 224 Cylinder section 225 Flange section 226 Lid section 240 Exterior space 243, 243a, 243b, 243c, 243d Inter-port space 261 Heating section S11 to S14, S23 to S24 Steps

Claims (11)

A separation device comprising:
A separation membrane composite including a porous support and a separation membrane formed on a surface of the support;
an outer cylinder that houses the separation membrane composite;
an exterior body that houses the outer cylinder therein;
a supply unit that supplies a fluid having a temperature higher than the temperature around the exterior body to an inside of the outer cylinder;
Equipped with
The outer cylinder is
a first discharge port for discharging non-permeating substances, which are substances other than the permeating substances that have permeated the separation membrane composite, from the fluid to the outside of the outer cylinder;
a second discharge port for discharging the permeated material from the fluid to the outside of the outer cylinder;
Equipped with
the first exhaust port and the second exhaust port are each provided on the outer cylinder within the exterior body;
one of the permeable substance and the non-permeable substance discharged from the outer cylinder can be introduced into an outer cylinder space, which is a space between the outer cylinder and the outer cylinder inside the outer cylinder, through an introduction port, which is one of the first discharge port and the second discharge port of the outer cylinder;
the exterior body includes an exterior body discharge port capable of discharging the one substance introduced into the exterior space through the introduction port to an outside of the exterior body,
an inter-port space, which is a space surrounded by the exterior body, the inlet port, and the exterior body outlet port, contains 50% by volume or more of the separation membrane composite;
the inter-port space is an internal space of the exterior body, and is a space sandwiched between an inlet port plane and an exterior body exhaust port plane which are parallel to each other;
the introduction port plane is a plane perpendicular to a line connecting a center of the introduction port of the outer cylinder and a center of the exterior body discharge port, and passing through the center of the introduction port;
A separation device, characterized in that the exterior body discharge port plane is a plane perpendicular to the straight line and passing through the center of the exterior body discharge port. 2. The separation device of claim 1,
A separation device, characterized in that the exterior space exists at least in a normal direction to a main surface of the separation membrane. A separation device according to claim 1 or 2,
The outer cylinder is
A tube portion having an opening at at least one end;
a flange portion extending outward from the cylindrical portion around the opening;
a cover portion that is fixed to the flange portion while covering the opening to seal the opening;
A separation device comprising: A separation device according to any one of claims 1 to 3,
A separation device, wherein said one material is said permeable material. A separation device according to any one of claims 1 to 4,
The separation device further comprises a heating section for heating the fluid before it is supplied to the outer cylinder. A separation device according to any one of claims 1 to 5,
A separation apparatus, wherein the fluid supplied by the supply unit has a temperature of 70° C. or higher. A separation device according to any one of claims 1 to 6,
A separation device further comprising a heat insulating section disposed around the exterior body to insulate at least a portion of an outer surface of the exterior body. A separation device according to any one of claims 1 to 7,
The separation device, wherein the separation membrane is a zeolite membrane. 9. The separation device according to claim 8,
A separation device characterized in that the maximum number of rings of the zeolite constituting the zeolite membrane is 8 or less. A separation device according to claim 8 or 9,
The fluid comprises one or more of the following substances: hydrogen, helium, nitrogen, oxygen, water, water vapor, carbon monoxide, carbon dioxide, nitrogen oxides, ammonia, sulfur oxides, hydrogen sulfide, sulfur fluoride, mercury, arsine, hydrogen cyanide, carbonyl sulfide, C1 to C8 hydrocarbons, organic acids, alcohols, mercaptans, esters, ethers, ketones, and aldehydes. A method for operating a separation device including a separation membrane composite including a porous support and a separation membrane formed on a surface of the support, an outer cylinder that houses the separation membrane composite, and an exterior body that houses the outer cylinder, comprising:
The outer cylinder is
a first discharge port for discharging non-permeating substances, which are substances other than the permeating substances that have permeated the separation membrane composite, to the outside of the outer cylinder ;
a second discharge port for discharging the permeated material to the outside of the outer cylinder;
Equipped with
the first exhaust port and the second exhaust port are each provided on the outer cylinder within the exterior body;
one of the permeable substance and the non-permeable substance discharged from the outer cylinder can be introduced into an outer cylinder space, which is a space between the outer cylinder and the outer cylinder inside the outer cylinder, through an introduction port, which is one of the first exhaust port and the second exhaust port of the outer cylinder;
the exterior body includes an exterior body discharge port capable of discharging the one substance introduced into the exterior space through the introduction port to an outside of the exterior body,
an inter-port space, which is a space surrounded by the exterior body, the inlet port, and the exterior body outlet port, contains 50% by volume or more of the separation membrane composite;
the inter-port space is an internal space of the exterior body, and is a space sandwiched between an inlet port plane and an exterior body exhaust port plane that are parallel to each other,
the introduction port plane is a plane perpendicular to a line connecting a center of the introduction port of the outer cylinder and a center of the exterior body discharge port, and passing through the center of the introduction port;
the exterior body discharge port plane is a plane perpendicular to the straight line and passing through a center of the exterior body discharge port,
The method for operating the separation apparatus includes:
a) supplying a fluid having a temperature higher than the temperature of the surroundings of the outer casing to the inside of the outer casing;
b) introducing one of the permeable material and the non-permeable material into the exterior space through the introduction port;
c) discharging the one substance from the exterior space through the inter-port space;
A method for operating a separation apparatus comprising:

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