Transient operation method for separation device

Abstract

Provided is a transient operation method for a separation device comprising a separation membrane complex, the transient operation method allowing for prevention of damage to the separation device and the separation membrane complex.　The transient operation method for a separation device according to the present invention is for a separation device comprising a separation membrane complex having a separation membrane and a base material disposed on one side of the separation membrane. The separation device has a first flow path and a second flow path. The first flow path is located on the separation membrane side of the separation membrane complex, and the second flow path is located on the base material side of the separation membrane complex. The transient operation method includes supplying a gas to the first flow path and the second flow path, and heating the separation membrane complex. The average relative humidity of gas A that is supplied to the first flow path is higher than the average relative humidity of gas B that is supplied to the second flow path.

Description

Transient operation method for separation device

[0001] The present invention relates to a method for transient operation of a separation device.

[0002] Membrane separation methods are known that use a separation membrane to separate a specific substance from a mixture. For example, a separation method using a zeolite membrane has been proposed (see Non-Patent Document 1). In a separation device equipped with a separation membrane, the separation membrane may need to be heated when the device is started up so that the separation membrane can perform its intended function.

[0003] Development of a Membrane-Assisted Reactor, Mitsui Zosen Technical Report, February 2003, No. 178, 115-120

[0004] A primary object of the present invention is to provide a method for transient operation of a separation apparatus equipped with a separation membrane composite, which can prevent damage to the separation apparatus and the separation membrane composite.

[0005] [1] A method for transient operation of a separation apparatus according to an embodiment of the present invention is a method for transient operation of a separation apparatus comprising a separation membrane composite having a separation membrane and a substrate disposed on one side of the separation membrane, the separation apparatus having a first flow path and a second flow path, the first flow path being located on the separation membrane side of the separation membrane composite and the second flow path being located on the substrate side of the separation membrane composite, the method including supplying gases to the first flow path and the second flow path and heating the separation membrane composite, wherein the average relative humidity of gas A supplied to the first flow path is higher than the average relative humidity of gas B supplied to the second flow path. [2] In the method for transient operation of a separation apparatus described in [1] above, the average relative humidity of gas B may be 10% or less. [3] In the method for transient operation of a separation apparatus described in [1] or [2] above, the separation membrane may be a zeolite membrane. [4] In the method for transient operation of a separation apparatus described in any of [1] to [3] above, the zeolite membrane may be made of LTA-type zeolite. [5] Another embodiment of the present invention provides a method for transient operation of a separation apparatus, the method comprising: a separation membrane assembly having a separation membrane and a substrate disposed on one side of the separation membrane; the separation apparatus having a first flow path and a second flow path; the first flow path being located on the separation membrane side of the assembly; and the second flow path being located on the substrate side of the assembly; the method comprising supplying gases to the first flow path and the second flow path; and heating the separation membrane assembly; wherein the relative humidity of gas A supplied to the first flow path is higher than the relative humidity of gas B supplied to the second flow path. [6] The transient operation method described in any of [1] to [5] above may be a start-up method. [7] The transient operation method described in any of [1] to [5] above may be a shutdown method.

[0006] According to an embodiment of the present invention, it is possible to provide a method for transient operation of a separation apparatus including a separation membrane composite, which can prevent damage to the separation apparatus and the separation membrane composite.

[0007] Fig. 1 is a schematic diagram of a separation membrane composite used in a transient operation method for a separation apparatus according to one embodiment of the present invention. Fig. 2 is a schematic diagram of the separation membrane and substrate of Fig. 1. Fig. 3 is a schematic diagram of a modified separation membrane composite. Fig. 4 is a schematic cross-sectional view of the separation membrane composite of Fig. 3. Fig. 5 is a schematic diagram of another modified separation membrane composite. Fig. 6 is a schematic diagram for explaining a method for operating a separation apparatus according to one embodiment of the present invention.

[0008] Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to these embodiments. In addition, in order to clarify the description, the drawings may show the width, thickness, shape, etc. of each part more schematically than in the embodiment, but these are merely examples and do not limit the interpretation of the present invention.

[0009] A. Transient Operation Method of Separation Apparatus Figure 1 is a schematic diagram of a separation membrane composite used in a transient operation method of a separation apparatus according to one embodiment of the present invention; Figure 2 is a schematic diagram of the separation membrane and substrate of Figure 1.

[0010] A method for transient operation of a separation device according to one embodiment of the present invention is a method for transient operation of a separation device 1 including a separation membrane composite 10 having a separation membrane 2 and a substrate 3 disposed on one side of the separation membrane 2. The separation device 1 has a first flow path 21 and a second flow path 22. The first flow path 21 is located on the separation membrane 2 side of the separation membrane composite 10. More specifically, the first flow path 21 may be located closer to the separation membrane 2 side of the separation membrane composite 10 than the substrate 3, and other elements (not shown) may or may not be present between the separation membrane 2 and the first flow path 21. The second flow path 22 is located on the substrate 3 side of the separation membrane composite 10. More specifically, the second flow path 22 may be located closer to the substrate 3 side of the separation membrane composite 10 than the separation membrane 2, and other elements (not shown) may or may not be present between the substrate 3 and the second flow path 22. Although not shown, the separation membrane composite 10 may include any other appropriate elements as long as the effects of the present invention are achieved. For example, the separation membrane 2 may be provided with a layer or powder that protects all or part of the separation membrane 2, an element having a separation function such as another separation membrane, or another substrate (for example, a layer that is thinner than the substrate 3 and has the same composition as the substrate 3) arranged on the opposite side of the separation membrane 2 from the substrate 3. Furthermore, the substrate 3 may be partially exposed.

[0011] The transient operation method of the separation apparatus includes supplying gas to the first flow path 21 and the second flow path 22 and changing the temperature of the separation membrane composite 10 (i.e., heating or cooling). Below, an embodiment in which the separation membrane composite 10 is heated will be described as a representative example. In one embodiment, the separation membrane composite 10 is heated by supplying gas to the first flow path 21 and the second flow path 22. The separation membrane composite 10 may also be heated by external heating (e.g., heating using any appropriate heating device). In one embodiment, in the transient operation method, the average relative humidity of gas A supplied to the first flow path 21 is higher than the average relative humidity of gas B supplied to the second flow path 22. In this specification, the average relative humidity is the average value of the relative humidity at the upstream end and the relative humidity at the downstream end of each flow path. More specifically, for each flow path, the inlet relative humidity calculated from the inlet temperature and water vapor partial pressure is RH1, and the outlet relative humidity calculated from the outlet temperature and water vapor partial pressure is RH2. The average relative humidity is calculated by the formula (RH1 + RH2) / 2. The relative humidity is the ratio of the measured water vapor partial pressure to the saturated water vapor pressure at a given temperature. In this specification, the relative humidity is measured using a dew point meter (capacitive type). Relative humidity measured by other methods may also be close to the relative humidity measured by the above method. For example, a relative humidity measured by collecting gas from a predetermined measurement position, measuring the proportion of condensable components by cooling, and analyzing the proportion of water contained in the condensable components by liquid chromatography may also be close to the above. The relative humidity at the downstream end of each flow path may also show a similar trend to the above average relative humidity. In one embodiment, gas is supplied to the first flow path under conditions that do not cause condensation on the separation membrane composite. In one embodiment, the gas is supplied to the second flow path under conditions that do not cause condensation on the separation membrane composite.

[0012] In one embodiment, the relative humidity (hereinafter also referred to as relative humidity (AU)) of gas A supplied to the first flow path 21 at the downstream end of the first flow path 21 is higher than the relative humidity (hereinafter also referred to as relative humidity (BU)) of gas B supplied to the second flow path 22 at the downstream end of the second flow path 22.

[0013] In one embodiment, after starting the separation device 1 by the transient operation method, heating continues until the separation membrane reaches a predetermined temperature, and the separation device then transitions to steady-state operation. During steady-state operation, a fluid that permeates the separation membrane 2 (e.g., a mixture containing water as a permeable substance and an organic compound that is less permeable) is supplied to the first flow path 21. The substance that has permeated the separation membrane 2 flows through the second flow path 22. By heating the separation membrane composite 10 by the transient operation method, the separation membrane 2 can exhibit a predetermined separation ability during steady-state operation.

[0014] In an embodiment of the present invention, by lowering the average relative humidity of gas B supplied to the second flow path 22, i.e., gas B supplied to the substrate 3 side, or the relative humidity at the downstream end of the flow path, it is possible to suppress bumping, sudden expansion, thermal shock, etc. of water within the substrate 3, and prevent damage to the separation membrane composite 10 and / or the separation device 1. In one embodiment, the moisture content (relative humidity) of gas A supplied to the first flow path is set to a certain amount or more. Supplying a gas containing moisture at startup can prevent damage to the separation membrane. Furthermore, in the present invention, by lowering the average relative humidity of gas B or the relative humidity at the downstream end of the flow path, problems caused by water content (breakage of the separation membrane due to bumping, sudden expansion, thermal shock, etc. of water) can be solved.

[0015] The difference between the average relative humidity of gas B and the average relative humidity of gas A (average relative humidity (%) of gas B - average relative humidity (%) of gas A) is preferably greater than 2% (points) and not greater than 95% (points), more preferably 2% (points) to 50% (points), and even more preferably 2% (points) to 15% (points). Within such a range, the above-mentioned effects become significant. Furthermore, damage to the separation membrane 2 during heating can be prevented. For example, when the average relative humidity of gas B is 70% and the average relative humidity of gas A is 50%, the difference between the average relative humidity of gas B and the average relative humidity of gas A (average relative humidity (%) of gas B - average relative humidity (%) of gas A) is 20%.

[0016] The difference between the relative humidity (BU) of gas B and the relative humidity (AU) of gas A (relative humidity (BU) (%) - relative humidity (AU) (%) of gas A) is preferably greater than 2% (points) and not more than 95% (points), more preferably 2% (points) to 50% (points), and even more preferably 2% (points) to 15% (points). Within this range, the above-mentioned effects become significant. Furthermore, damage to the separation membrane 2 during heating can be prevented.

[0017] The average relative humidity of the gas A is preferably 0.1% or more, more preferably 0.5% or more, and even more preferably 5% or more. Within this range, damage to the separation membrane 2 during heating can be prevented. Furthermore, the measuring equipment can be simplified. Furthermore, general-purpose measuring equipment can be used, thereby reducing costs. Furthermore, the upper limit of the average relative humidity of the gas A is, for example, 100%, more preferably 95%. Within this range, damage to the separation membrane 2 during heating can be prevented. Furthermore, by setting the average relative humidity of the gas A to 95% or less, the effects of the present invention can be stably obtained.

[0018] The relative humidity (AU) of the gas A is preferably 0.1% or more, more preferably 0.5% or more, and even more preferably 5% or more. Within this range, damage to the separation membrane 2 during heating can be prevented. Furthermore, the measuring equipment can be simplified. Furthermore, general-purpose measuring equipment can be used, thereby reducing costs. Furthermore, the upper limit of the relative humidity (AU) of the gas A is, for example, 100%, more preferably 95%. Within this range, damage to the separation membrane 2 during heating can be prevented. Furthermore, by setting the relative humidity (AU) of the gas A to 95% or less, the effects of the present invention can be stably obtained.

[0019] The average relative humidity of the gas B is preferably 10% or less, more preferably 5% or less. Within this range, bumping of water, sudden expansion, thermal shock, etc. can be suppressed, and damage to the separation membrane composite 10 and / or the separation device 1 can be significantly prevented. The lower limit of the average relative humidity of the gas B is not particularly limited, but is, for example, 0.01%, more preferably 0.05%. Within this range, the dryer performance in the compressor can be simplified.

[0020] The relative humidity (BU) of the gas B is preferably 10% or less, more preferably 5% or less. Within this range, bumping of water, sudden expansion, thermal shock, etc. can be suppressed, and the effect of preventing damage to the separation membrane composite 10 and / or the separation device 1 is significant. The lower limit of the relative humidity (BU) of the gas B is not particularly limited, but is, for example, 0.01%, more preferably 0.05%. Within this range, the dryer performance in the compressor can be simplified.

[0021] In one embodiment, the pressure in the first flow path 21 and / or the second flow path 22 is adjusted depending on the environmental temperature in which the separation membrane assembly 10 (substantially the separation membrane 2) is placed. In the method for transient operation of a separation apparatus, the initial temperature of the separation membrane 2 is, for example, 0°C to 35°C, and the initial pressure in the first flow path 21 is, for example, 0.1 MPaG to 20 MPaG. Furthermore, at the completion of start-up of the separation apparatus, the temperature of the separation membrane 2 is, for example, 100°C to 350°C, and the pressure in the first flow path 21 is, for example, 0.1 MPaG to 20 MPaG.

[0022] In this specification, the term "transient operation method" is a concept that includes a start-up method and a shutdown method. Therefore, in the description of the above-described embodiment, the term "transient operation method" may be referred to as a "start-up method" (i.e., the term "transient operation method" may be read as a "start-up method") or a "shut-down method." In this specification, the term "start-up method" refers to a method that includes heating the separation membrane. Furthermore, the term "shut-down method" refers to a method that includes lowering the temperature of the separation membrane.

[0023] B. Separation Device B-1. Separation Membrane Composite As shown in FIG. 1, a separation device 1 typically includes a separation membrane composite 10 including a substrate 3 and a separation membrane 2. Although not shown, the separation membrane composite 10 is housed in any suitable case when used. The separation membrane composite 10 typically extends in the same direction as the first flow path 21. The length of the separation membrane composite 10 can be adjusted arbitrarily and appropriately.

[0024] B-1-1. Substrate The substrate 3 supports the separation membrane 2. In one embodiment, the substrate 3 is a porous substrate. The porous substrate has, for example, a so-called monolith structure, and includes a skeleton that is continuous in the form of a three-dimensional network and interconnected pores defined by the skeleton. The substrate 3 may contain components that constitute the separation membrane 2.

[0025] The porous substrate may be made of any suitable material. Typical examples of the material for the porous substrate include ceramic sintered bodies. Examples of ceramic sintered bodies include alumina, silica, mullite, zirconia, titania, yttria, silicon nitride, silicon carbide, and cordierite. The ceramic sintered bodies may be used alone or in combination. Of the ceramic sintered bodies, alumina is preferred.

[0026] The porous substrate may contain an inorganic binder. Examples of inorganic binders include titania, mullite, sinterable alumina, silica, glass frit, clay minerals, and sinterable cordierite. The inorganic binders may be used alone or in combination.

[0027] The porous substrate may be composed of a single layer or may have a multilayer structure in which multiple layers are stacked. In one embodiment, the porous substrate has a multilayer structure having multiple layers with different pore sizes, as shown in Figure 2. In this case, it is preferable that the pore size is smaller as the layer is closer to the separation membrane 2.

[0028] The average pore diameter of the porous substrate is, for example, 0.01 μm to 70 μm, preferably 0.05 μm to 25 μm. The average pore diameter of the porous substrate on the separation membrane side is 0.01 μm to 1 μm, preferably 0.05 μm to 0.5 μm. With regard to the pore size distribution throughout the porous substrate, including the surface and interior, D5 is, for example, 0.01 μm to 50 μm, D50 is, for example, 0.05 μm to 70 μm, and D95 ​​is, for example, 0.1 μm to 2000 μm. The porosity of the porous substrate on the separation membrane side is, for example, 25% to 50%. The average pore diameter of the porous substrate can be measured, for example, using a mercury porosimeter, perm porometer, or nanoperm porometer.

[0029] As shown in FIG. 1 , the substrate 3 typically separates the first flow path 21 and the second flow path 22. The substrate 3 may have any suitable shape. Examples of the shape of the substrate 3 include a cylindrical shape, a honeycomb shape, and a flat plate shape. In one embodiment, the substrate 3 is a cylindrical substrate 3a. Examples of the cross-sectional shape of the cylindrical substrate 3a in a direction perpendicular to the longitudinal direction include a triangle, a rectangle, a pentagon, a polygon having hexagons or more, a circle, and an ellipse, and a circle is preferred. The outer diameter and length of the cylindrical substrate can be appropriately set depending on the purpose.

[0030] In this embodiment, the internal space of the cylindrical substrate 3a (the space defined by the inner peripheral surface of the cylindrical substrate) includes either the first flow path 21 or the second flow path 22, and the external space of the cylindrical substrate 3a (the space outside the outer peripheral surface of the cylindrical substrate) includes the other of the first flow path 21 or the second flow path 22. In the illustrated example, the internal space of the cylindrical substrate 3a includes the first flow path 21, and the external space of the cylindrical substrate 3a includes the second flow path 22.

[0031] 3 and 4, the substrate 3 is a honeycomb substrate 3b. The honeycomb substrate 3b has partition walls 33 that define a plurality of cells 34. The cells 34 are formed in a cylindrical shape so as to penetrate the honeycomb substrate 3b in the length direction.

[0032] The cells 34 extend in the length direction (axial direction) of the honeycomb substrate 3b from the first end face E1 (inlet end face) to the second end face E2 (outlet end face) of the honeycomb substrate 3b (see FIG. 4). The cells 34 have any appropriate shape in a cross section perpendicular to the length direction of the honeycomb substrate 3b. Examples of the cross-sectional shape of the cells include triangles, rectangles, pentagons, polygons with hexagons or more, circles, and ellipses. The cross-sectional shapes and sizes of the cells may all be the same, or at least some may be different. Among such cross-sectional shapes of the cells, a circle is preferred.

[0033] The distance between the central axes of the plurality of cells 34 is, for example, 0.3 mm to 20 mm. The cell density in the cross section perpendicular to the longitudinal direction of the honeycomb substrate (i.e., the number of cells 34 per unit area) can be appropriately set depending on the purpose. The cell density is, for example, 0.5 cells / cm. ２ ~320 cells / cm ２ If the cell density is in this range, the strength and effective GSA (geometric surface area) of the honeycomb substrate can be sufficiently ensured.

[0034] The honeycomb substrate 3b may have any suitable shape (overall shape). Examples of the shape of the honeycomb substrate include a cylindrical shape with a circular bottom, an elliptical cylindrical shape with an elliptical bottom, a rectangular prism with a polygonal bottom, and a cylindrical shape with an irregular bottom. The honeycomb substrate 3b in the illustrated example has a cylindrical shape. The outer diameter and length of the honeycomb substrate can be appropriately set depending on the purpose.

[0035] In this embodiment, the internal space of each of the plurality of cells 34 (the space defined by the inner peripheral surface of the cell) includes either the first flow path 21 or the second flow path 22, and the external space of the honeycomb substrate 3 b (the space outside the outer peripheral surface of the honeycomb substrate) includes the other of the first flow path 21 or the second flow path 22. In the illustrated example, the internal space of the cell 34 includes the first flow path 21, and the external space of the honeycomb substrate 3 b includes the second flow path 22.

[0036] B-1-2. Separation Membrane The separation membrane 2 is typically provided directly on the surface of the substrate 3. The separation membrane 2 may face the first flow path 21 (see FIGS. 1 and 4) or may face the second flow path 22 (see FIG. 5).

[0037] In one embodiment, the separation membrane 2 faces the first flow path 21. In FIG. 1 , the substrate 3 is a cylindrical substrate 3 a, and the separation membrane 2 is formed on the inner surface of the cylindrical substrate 3 a. In the illustrated example, the first flow path 21 is formed in a portion (typically the central portion) of the cross section of the separation membrane composite 10 where the separation membrane 2 is not formed. In FIG. 4 , the substrate 3 is a honeycomb substrate 3 b, and the separation membrane 2 is formed on the inner surface of each of the multiple cells 34. The first flow path 21 is formed in a portion (typically the central portion) of the cross section of the cell 34 where the separation membrane 2 is not formed. As in the illustrated example, the separation membrane 2 may be formed on the entire inner surface of the cylindrical substrate 3 a or the cell 34 (i.e., so as to surround the first flow path 21), or may be formed on a portion of the inner surface of the cylindrical substrate 3 a or the cell 34. Forming the separation membrane so as to surround the first flow path can improve separation efficiency.

[0038] The separation membrane 2 allows specific substances to permeate and separate them from a mixture by utilizing, for example, differences in molecular size and / or differences in adsorption properties.

[0039] The separation membrane 2 may be made of any appropriate material. Examples of materials for the separation membrane 2 include zeolite, MOF, and silica. These materials may be used alone or in combination.

[0040] When the adsorbent to be separated contains water, zeolite is preferably used as the material of the separation membrane 2. In one embodiment, the separation membrane 2 is a zeolite membrane.

[0041] The zeolite membrane is formed by forming a film of zeolite on the surface of a substrate. The zeolite membrane may contain two or more types of zeolite with different structures and compositions.

[0042] As the zeolite constituting the zeolite membrane, for example, oxygen tetrahedron (TO ４) zeolites in which the atom (T atom) located at the center of the zeolite is composed of only Si or of Si and Al; AlPO zeolites in which the T atoms are composed of Al and P; SAPO zeolites in which the T atoms are composed of Si, Al, and P; MAPSO zeolites in which the T atoms are composed of magnesium (Mg), Si, Al, and P; and ZnAPSO zeolites in which the T atoms are composed of zinc (Zn), Si, Al, and P. Some of the T atoms may be substituted with other elements.

[0043] Examples of the zeolite include AEI, AEN, AFN, AFV, AFX, BEA, CHA, DDR, ERI, ETL, FAU (X, Y), GIS, LEV, LTA, MEL, MFI, MOR, PAU, RHO, SAT, and SOD types. Among these zeolites, LTA type zeolite is particularly preferred.

[0044] The maximum number of ring members in the zeolite is, for example, 12 or less, preferably 10 or less, more preferably 8 or less, and for example, 6 or more.

[0045] The zeolite membrane is made of SiO ２ and Al ２ O ３ The zeolite membrane may further contain an alkali metal, such as sodium (Na) or potassium (K).

[0046] SiO in zeolite membranes ２ / Al ２ O ３ The molar ratio of SiO in the zeolite membrane is, for example, 100 or less, preferably 10 or less, more preferably 5 or less, and even more preferably less than 5. ２ / Al ２ O ３ When the molar ratio of SiO in the zeolite membrane is equal to or less than the upper limit, the zeolite membrane can be more stably prevented from being damaged. ２ / Al ２ O ３ The lower limit of the molar ratio of SiO is typically 2. ２ / Al ２ O ３The molar ratio can be measured, for example, by scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDX; X-ray acceleration voltage 10 kV).

[0047] The average pore size of the separation membrane 2 can be arbitrarily and appropriately selected depending on the substance to be separated. The average pore size of the separation membrane 2 is, for example, 0.2 nm to 1 nm, and preferably 0.3 nm to 0.5 nm. Reducing the average pore size of the separation membrane 2 increases selectivity. The average pore size of the separation membrane 2 is smaller than the average pore size of the substrate 3. When the separation membrane 2 is a zeolite membrane, the maximum number of rings in the zeolite is n, and the average pore size is the arithmetic mean of the minor and major axes of the n-membered ring pores. An n-membered ring pore is a pore in which the number of oxygen atoms in the portion where an oxygen atom is bonded to a T atom to form a ring structure is n. When there are multiple n-membered ring pores with the same n, the arithmetic mean of the minor and major axes of all the n-membered ring pores is the average pore size of the zeolite. The average pore size of a zeolite membrane is determined by the framework structure of the zeolite, and can be determined from the values ​​disclosed in the "Database of Zeolite Structures" [online] of the International Zeolite Society, available on the Internet at <URL: http: / / www.iza-structure.org / databases / >.

[0048] The thickness of the separation membrane 2 is, for example, 0.05 μm to 30 μm, preferably 0.1 μm to 20 μm, and more preferably 0.5 μm to 10 μm. A thicker separation membrane increases selectivity. A thinner separation membrane increases permeation rate.

[0049] The surface roughness (Ra) of the separation membrane 2 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 surface roughness (Ra) can be measured, for example, in accordance with JIS B 0601.

[0050] The separation membrane 2 can be formed by any appropriate method depending on the material constituting the membrane. For example, a zeolite membrane can be obtained by applying zeolite as seed crystals to a separation membrane, immersing the substrate with the seed crystals attached in a raw material solution, and growing zeolite using the seed crystals as nuclei by hydrothermal synthesis. The raw material solution contains, for example, a silica source, an alumina source, an organic substance, an alkali source, and water. The heating temperature in the hydrothermal synthesis is, for example, 60°C to 200°C. The heating time is, for example, 1 hour to 240 hours. Alternatively, the separation membrane may be formed using a raw material slurry obtained by mixing an organic binder, a ceramic raw material, and a solvent.

[0051] B-2. Other Configurations The separation device 1 may include any appropriate elements in addition to the separation membrane composite 10. For example, it may include a supply unit for supplying fluids (gas supplied at startup, the mixture supplied after startup), a heating device for heating the fluids, a recovery unit for recovering the fluids after passing through the separation membrane composite, etc. Examples of heating devices include reactors that involve chemical reactions, heaters, heat exchangers, etc. The separation device 1 may further include a pressure adjustment unit that can adjust the pressure of the first flow path 21 and / or the second flow path 22 in the separation membrane composite 10. The separation device 1 may further include a control unit that can control the operation of the separation device 1. Configurations of the separation device other than the separation membrane composite are described, for example, in International Publication No. 2018 / 225325. The disclosure of this publication is incorporated herein by reference.

[0052] In one embodiment, as shown in Figure 6, the separation device 1 further includes, in addition to the separation membrane composite 10, a supply section 4 that supplies a mixture to a first flow path 21 of the separation membrane composite 10; a first recovery section 5 that recovers a fluid that has passed through the first flow path 21; and a second recovery section 6 that recovers a permeate that has permeated the separation membrane 2. The separation device 1 in the illustrated example is configured to be able to adjust the temperature, pressure, and flow rate of the mixture passing through the first flow path. Note that Figure 6 illustrates one embodiment of the present invention, and the present invention is not limited thereto.

[0053] The supply unit 4 in the illustrated example is capable of adjusting the temperature and flow rate of the mixture supplied (flowing into) the first flow path 21. The supply unit 4 includes a supply line 41, a heating device 42, and a flow regulator 43. The supply line 41 is a pipe for supplying the mixture to the first flow path 21. The upstream end of the supply line 41 in the supply direction of the mixture is connected to, for example, a storage tank (not shown) that stores the mixture. The downstream end of the supply line 41 in the supply direction of the mixture is connected to the inlet of the first flow path 21 included in the separation membrane composite 10. The heating device 42 is provided in the supply line 41 and is capable of heating the mixture passing through the supply line 41. The heating device 42 may have any appropriate configuration. The flow regulator 43 is capable of adjusting the flow rate of the mixture passing through the supply line 41. The flow regulator 43 may have any appropriate configuration. In the illustrated example, the flow regulator 43 is provided in the supply line 41 between the heating device 42 and the separation membrane composite 10. The supply unit 4 may include other devices as necessary. For example, other devices may be present in the supply line 41 between the flow rate regulator 43 and the separation membrane composite 10.

[0054] The first recovery section 5 in the illustrated example is capable of adjusting the pressure in the first flow path 21. The first recovery section 5 includes a first recovery line 51 and a pressure adjustment valve 52. The first recovery line 51 is a pipe through which the fluid passes after passing through the first flow path 21 provided in the separation membrane composite 10. The upstream end of the first recovery line 51 in the direction of fluid passage is connected to the outlet of the first flow path 21 provided in the separation membrane composite 10. The downstream end of the first recovery line 51 in the direction of fluid passage is connected to, for example, a storage tank (not shown). The pressure adjustment valve 52 is provided in the first recovery line 51. The pressure adjustment valve 52 can adjust the opening degree of the first recovery line 51, and therefore the pressure in the first flow path 21.

[0055] The second recovery section 6 in the illustrated example includes a second recovery line 61. The second recovery line 61 is a pipe through which a fluid passes from the second flow path 22 provided in the separation membrane composite 10 after passing through the second flow path 22. The upstream end of the second recovery line 61 in the fluid passage direction is connected to the outlet of the second flow path 22 provided in the separation membrane composite 10. The downstream end of the second recovery line 61 in the fluid passage direction is connected to, for example, a storage tank (not shown).

[0056] In the above-described embodiment, the supply unit 4 upstream of the separation membrane composite 10 adjusts the temperature and flow rate of the mixture supplied (flowing into) the first flow path 21, and the first recovery unit 5 downstream of the separation membrane composite 10 adjusts the pressure of the mixture in the first flow path 21, but the configuration of the separation device 1 is not limited to this. The supply unit 4 may be configured to be able to adjust the pressure of the mixture in the first flow path 21. Furthermore, the first recovery unit 5 may be configured to be able to adjust the flow rate of the mixture passing through the first flow path 21.

[0057] The transient operation method of a separation apparatus according to an embodiment of the present invention can be used to separate a specific substance in a mixture, and can be particularly suitably used to separate water from a water-containing mixture.

[0058] REFERENCE SIGNS LIST 1 Separation device 2 Separation membrane 3 Substrate 21 First flow path 22 Second flow path

Claims

1. A method for transient operation of a separation device equipped with a separation membrane composite having a separation membrane and a substrate disposed on one side of the separation membrane, wherein the separation device has a first flow path and a second flow path, the first flow path being located on the separation membrane side of the separation membrane composite and the second flow path being located on the substrate side of the separation membrane composite, the method comprising supplying gases to the first flow path and the second flow path and heating the separation membrane composite, wherein the average relative humidity of gas A supplied to the first flow path is higher than the average relative humidity of gas B supplied to the second flow path.

2. The transient operation method for a separation apparatus according to claim 1, wherein the average relative humidity of said gas B is 10% or less.

3. The transient operation method for a separation apparatus according to claim 1 or 2, wherein the separation membrane is a zeolite membrane.

4. The transient operation method for a separation apparatus according to claim 3, wherein the zeolite membrane is made of LTA type zeolite.

5. A method for transient operation of a separation device equipped with a separation membrane composite having a separation membrane and a substrate arranged on one side of the separation membrane, wherein the separation device has a first flow path and a second flow path, the first flow path being located on the separation membrane side of the separation membrane composite and the second flow path being located on the substrate side of the separation membrane composite, the method comprising supplying gases to the first flow path and the second flow path and heating the separation membrane composite, wherein the relative humidity of gas A supplied to the first flow path is higher than the relative humidity of gas B supplied to the second flow path.

6. A transient operation method according to claim 1 or 2, which is a startup method.

7. A transient operation method according to claim 1 or 2, which is a shutdown method.