Transient operation method for separation device

Abstract

Provided is a transient operation method for a separation device with which a separation membrane can be efficiently heated.　The transient operation method for a separation device according to an embodiment of the present invention comprises 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 heating the separation membrane complex through gas supply to at least the second flow path. The gas that is supplied to the second flow path satisfies formula (1).　(1): ΔCp2 / ΔT2 < 0(J / (mol･K2)) ΔCp2: difference between molar specific heat a at constant pressure at entrance of second flow path for separation membrane complex and molar specific heat b at constant pressure at exit of second flow path for separation membrane complex ΔT2: difference between gas temperature a at entrance of second flow path for separation membrane complex and gas temperature b at exit of second flow path for separation membrane complex

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 separation membranes to separate specific substances from a mixture. For example, a separation method using a zeolite membrane has been proposed as one such membrane separation method (see Non-Patent Document 1). In a separation device equipped with a separation membrane, the separation membrane may need to be heated at the start of the device so that the separation membrane can perform its intended function. In this case, efficient heating across the entire separation membrane is required.

[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, which method is capable of efficiently heating the separation membrane.

[0005] [1] A transient operation method for a separation device according to an embodiment of the present invention is 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, the separation device 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 heating the separation membrane composite by supplying a gas to at least the second flow path, and the gas supplied to the second flow path satisfying the following formula (1): ΔCp ２ / ΔT ２ <0(J / (mol・K ２ ))...(1) ΔCp ２ ΔT: the difference between the constant pressure molar specific heat a at the inlet of the separation membrane composite of the second flow path and the constant pressure molar specific heat b at the outlet of the separation membrane composite of the second flow path (constant pressure molar specific heat a - constant pressure molar specific heat b) (unit: J / (mol K)), ２ΔCp of the gas supplied to the second flow path is a difference (gas temperature a - gas temperature b) (unit: K) between the gas temperature a at the inlet of the separation membrane composite of the second flow path and the gas temperature b at the outlet of the separation membrane composite of the second flow path. [2] A method for transient operation of a separation device according to an embodiment of the present invention is a method for transient operation of a separation device comprising a separation membrane composite having a separation membrane and a substrate arranged on one side of the separation membrane, the separation device 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 comprising heating the separation membrane composite by supplying gas to the first flow path and the second flow path, ２ / ΔT ２ is the ΔCp of the gas supplied to the first flow path １ / ΔT １ ΔCp1 is the difference between the constant pressure molar specific heat c at the inlet of the separation membrane composite of the first flow path and the constant pressure molar specific heat d at the outlet of the separation membrane composite of the first flow path (constant pressure molar specific heat c - constant pressure molar specific heat d) (unit: J / (mol K)), and ΔT １ is the difference between the gas temperature c at the inlet of the separation membrane composite of the first flow path and the gas temperature d at the outlet of the separation membrane composite of the first flow path (gas temperature c - gas temperature d) (unit: K), and ΔCp ２ is the difference between the constant pressure molar specific heat a at the inlet of the separation membrane composite of the second flow path and the constant pressure molar specific heat b at the outlet of the separation membrane composite of the second flow path (constant pressure molar specific heat a - constant pressure molar specific heat b) (unit: J / (mol K)), and ΔT ２is the difference (gas temperature a - gas temperature b) (unit: K) between the gas temperature a at the inlet of the separation membrane composite of the second flow path and the gas temperature b at the outlet of the separation membrane composite of the second flow path. [3] In the method for transient operation of a separation apparatus according to the above item [2], the gas supplied to the second flow path may satisfy the above formula (1). [4] In the method for transient operation of a separation apparatus according to any of the above items [1] to [3], the gas supplied to the second flow path may contain water vapor. [5] In the method for transient operation of a separation apparatus according to the above item [4], the gas supplied to the second flow path may have a water vapor content of 10 mol% or more. [6] to [8] In the method for transient operation of a separation apparatus according to any of the above items [1] to [5], the gas temperature at the inlet of the separation membrane composite of the second flow path may be 100°C or more. [9] In the method for transient operation of a separation apparatus according to any of the above items [1] to [6], the separation membrane may be a zeolite membrane.

[10] In the transient operation method of a separation apparatus described in [9] above, the zeolite membrane may be made of LTA zeolite.

[11] The transient operation method described in any one of [1] to

[10] above may be a start-up method.

[12] The transient operation method described in any one of [1] to

[10] 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, which method can efficiently heat the separation membrane.

[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 for the separation device 1 includes changing the temperature of the separation membrane composite 10 (i.e., heating or cooling) by supplying gas to at least the second flow path 22. Below, an embodiment in which the separation membrane composite 10 is heated will be described as a representative example. Furthermore, the separation membrane composite 10 may be heated by supplying gas to the first flow path 21.

[0012] In one embodiment, after starting the separation device 1 by the transient operation method, heating continues until the separation membrane reaches a predetermined temperature (e.g., a temperature at which the separation membrane can perform its separation function), and the separation device transitions to steady-state operation. During steady-state operation, a fluid containing a substance 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 will exhibit a predetermined separation ability (e.g., separation ability based on permeability) during steady-state operation.

[0013] In one embodiment, the gas supplied to the second flow path 22 satisfies the following formula (1): ΔCp ２ / ΔT ２ <0(J / (mol・K ２ ))...(1) ΔCp ２ ΔT: the difference between the constant pressure molar specific heat a at the inlet of the separation membrane composite of the second flow path and the constant pressure molar specific heat b at the outlet of the separation membrane composite of the second flow path (constant pressure molar specific heat a - constant pressure molar specific heat b) (unit: J / (mol K)) ２ ΔCp: difference between gas temperature a at the inlet of the separation membrane composite of the second flow path and gas temperature b at the outlet of the separation membrane composite of the second flow path (gas temperature a - gas temperature b) (unit: K). ２ / ΔT ２ is more preferably smaller than −0.004, and even more preferably smaller than −0.007. ２ / ΔT ２ The lower limit of is, for example, −0.1.

[0014] In an embodiment of the present invention, ΔCp ２ / ΔT ２By setting the temperature difference specific heat coefficient (also referred to as the temperature difference specific heat coefficient) within the above range, the separation membrane composite can be heated efficiently. More specifically, it is expected that in the early stages of heating, heat transfer from the gas is more likely to occur upstream of the separation membrane composite and heating is less likely to occur downstream. In embodiments of the present invention, the temperature drop of the gas due to flow is suppressed, and the entire separation membrane composite can be heated efficiently. In conventional technology, a method can be used in which the flow rate of the heating gas is increased to promote heating downstream, but this requires the peripheral blowers and heating devices to be larger, resulting in increased energy consumption. According to embodiments of the present invention, the separation membrane composite can be heated efficiently as described above while suppressing the flow rate of the heating gas. In other words, in considering the heat exchange between the heating gas and the heated object, the temperature difference heat capacity coefficient (unit: W / K) is calculated by multiplying the temperature difference specific heat coefficient by the gas flow rate. ２ The major achievement of the present invention is that the temperature difference specific heat coefficient, rather than ΔT, is found to be the important factor. ２ is affected by the flow rate of the heating gas (at high flow rates, ΔT ２ In the embodiment of the present invention, ΔT ２ By specifying the heating gas based on a characteristic value including the above and controlling the characteristic value, the separation membrane composite can be heated appropriately and efficiently regardless of the gas flow rate.

[0015] In another embodiment, the ΔCp of the gas supplied to the second flow path ２ / ΔT ２ is the ΔCp of the gas supplied to the first flow path １ / ΔT １ In this embodiment, ΔCp ２ / ΔT ２ can be set within the above range (preferably smaller than 0, more preferably smaller than −0.004, and even more preferably smaller than −0.007). １ is the difference between the constant pressure molar specific heat c at the inlet of the separation membrane composite of the first flow path and the constant pressure molar specific heat d at the outlet of the separation membrane composite of the first flow path (constant pressure molar specific heat c - constant pressure molar specific heat d) (unit: J / (mol K), and ΔT １is the difference (gas temperature c−gas temperature d) (unit: K) between the gas temperature c at the separation membrane composite inlet of the first flow path and the gas temperature d at the separation membrane composite outlet of the first flow path. As described above, the constant pressure molar specific heat is the constant pressure molar specific heat at atmospheric pressure at the gas temperature at that location.

[0016] In a separation membrane composite including a substrate and a separation membrane, the substrate 3 is generally configured to have a higher heat capacity than the separation membrane 2. Therefore, as described above, ΔCp １ / ΔT １ and ΔCp ２ / ΔT ２ By specifying the above, it becomes possible to efficiently heat the separation membrane composite 10 (substantially the separation membrane 2).

[0017] ΔCp of the gas supplied to the first flow path １ / ΔT １ For example, 0 (J / (mol K ２ ))~0.06(J / (mol・K ２ )).

[0018] In one embodiment, the gas temperature at the inlet of the separation membrane composite of the second flow path is 100°C or higher. The gas temperature at the inlet of the separation membrane composite of the second flow path is preferably 100°C to 300°C, more preferably 130°C to 260°C. Within such a range, the above-mentioned effects become significant. Furthermore, even when heating to higher temperatures, the transient operation method of the present invention can be preferably used within the above temperature range. Naturally, when heating to a temperature exceeding the above range, a gas containing water vapor may be used subsequently. The gas temperature at the inlet of the separation membrane composite of the first flow path is, for example, 100°C to 300°C.

[0019] In one embodiment, the gas supplied to the second flow path contains water vapor. The temperature difference specific heat coefficient can be controlled by the water vapor content. In one embodiment, the gas is supplied to the second flow path under conditions that do not cause condensation on the separation membrane composite.

[0020] In one embodiment, the water vapor content of the gas supplied to the first flow path is lower than the water vapor content of the gas supplied to the second flow path. By using a highly humid gas as the gas supplied to the second flow path, it becomes possible to efficiently heat the separation membrane composite (e.g., it becomes possible to efficiently perform subsequent heating). In one embodiment, the gas is supplied to the first flow path under conditions that do not cause condensation on the separation membrane composite.

[0021] The water vapor content of the gas supplied to the second flow path is preferably 10 mol % or more, more preferably 20 mol % or more. Within this range, the efficiency of heating the separation membrane is significantly increased. The upper limit of the water vapor content of the gas supplied to the second flow path is, for example, 100 mol %. In one embodiment, the water vapor partial pressure P(H ２ O) and saturated water vapor pressure P ｓａｔ (H ２ O) and [P(H ２ O) / P ｓａｔ (H ２ 0)<1], the water vapor content of the gas supplied to the second flow path is set to the above range.

[0022] 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.

[0023] 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.

[0024] 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. In the separation membrane composite, the weight ratio of the substrate 3 to the separation membrane 2 (substrate / separation membrane) is, for example, 100 to 200,000. Furthermore, the heat capacity ratio of the substrate 3 to the separation membrane 2 (substrate / separation membrane) is, for example, 50 to 300,000.

[0025] 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.

[0026] The specific heat of the material constituting the substrate is, for example, 450 J / kgK to 1100 J / kgK.

[0027] The porous substrate may be made of any suitable material. Typical examples of the porous substrate include sintered ceramics. Examples of sintered ceramics include alumina, silica, mullite, zirconia, titania, yttria, silicon nitride, silicon carbide, and cordierite. The sintered ceramics may be used alone or in combination.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] The distance between the central axes of the plurality of cells 34 is, for example, 0.3 mm to 10 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, 4 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.

[0036] 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.

[0037] 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.

[0038] 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).

[0039] 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.

[0040] 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.

[0041] The separation membrane 2 may be made of any appropriate material. Typical examples of materials for the separation membrane 2 include inorganic materials. Examples of inorganic materials include zeolite, silica, and carbon. The inorganic materials may be used alone or in combination. The specific heat of the material that makes up the separation membrane 2 is, for example, 450 J / kgK to 900 J / kgK.

[0042] When the substance 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] The zeolite membrane is made of SiO ２ and Al２ O ３ The zeolite membrane may further contain an alkali metal, such as sodium (Na) or potassium (K).

[0048] 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, and more preferably 5 or less. ２ / Al ２ O ３ The lower limit of the molar ratio of SiO is typically 2. ２ / Al ２ O ３ The molar ratio can be measured, for example, by scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDX; X-ray acceleration voltage 10 kV).

[0049] 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 / >.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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, and heat exchangers. The separation device 1 may further include a pressure adjustment unit 7 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 8 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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).

[0058] 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.

[0059] 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.

[0060] 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, the separation device 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 comprising heating the separation membrane composite by supplying a gas to at least the second flow path, wherein the gas supplied to the second flow path satisfies the following formula (1): ΔCp ２ / ΔT ２ <0(J / (mol・K ２ ))...(1) ΔCp ２ ΔT: the difference between the constant pressure molar specific heat a at the inlet of the separation membrane composite of the second flow path and the constant pressure molar specific heat b at the outlet of the separation membrane composite of the second flow path (constant pressure molar specific heat a - constant pressure molar specific heat b) (unit: J / (mol K)), ２ : The difference between the gas temperature a at the inlet of the separation membrane composite in the second flow path and the gas temperature b at the outlet of the separation membrane composite in the second flow path (gas temperature a - gas temperature b) (unit: K).

2. 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, the separation device 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 comprising heating the separation membrane composite by supplying gas to the first flow path and the second flow path, and determining the ΔCp of the gas supplied to the second flow path. ２ / ΔT ２ is the ΔCp of the gas supplied to the first flow path １ / ΔT １ is smaller than the ΔCp １ is the difference between the constant pressure molar specific heat c at the inlet of the separation membrane composite of the first flow path and the constant pressure molar specific heat d at the outlet of the separation membrane composite of the first flow path (constant pressure molar specific heat c - constant pressure molar specific heat d) (unit: J / (mol K)), and ΔT １ is the difference between the gas temperature c at the inlet of the separation membrane composite of the first flow path and the gas temperature d at the outlet of the separation membrane composite of the first flow path (gas temperature c - gas temperature d) (unit: K), and ΔCp ２ is the difference between the constant pressure molar specific heat a at the inlet of the separation membrane composite of the second flow path and the constant pressure molar specific heat b at the outlet of the separation membrane composite of the second flow path (constant pressure molar specific heat a - constant pressure molar specific heat b) (unit: J / (mol K)), and ΔT ２ is the difference (gas temperature a-gas temperature b) (unit: K) between the gas temperature a at the inlet of the separation membrane composite of the second flow path and the gas temperature b at the outlet of the separation membrane composite of the second flow path.

3. The method for transient operation of a separation apparatus according to claim 2, wherein the gas supplied to the second flow path satisfies the following formula (1): ΔCp ２ / ΔT ２ <0(J / (mol・K ２ ))...(1).

4. The method for transient operation of a separation apparatus according to claim 1 or 2, wherein the gas supplied to the second flow path contains water vapor.

5. The method for transient operation of a separation apparatus according to claim 4, wherein the water vapor content of the gas supplied to the second flow path is 10 mol % or more.

6. The transient operation method for a separation apparatus according to any one of claims 1 to 3, wherein the gas temperature at the inlet of the separation membrane composite in the second flow path is 100°C or higher.

7. The transient operation method for a separation apparatus according to claim 4, wherein the gas temperature at the inlet of the separation membrane composite in the second flow path is 100°C or higher.

8. The method for transient operation of a separation apparatus according to claim 5, wherein the gas temperature at the inlet of the separation membrane composite in the second flow path is 100°C or higher.

9. The transient operation method for a separation apparatus according to any one of claims 1 to 3, wherein the separation membrane is a zeolite membrane.

10. The transient operation method for a separation device according to claim 9, wherein the zeolite membrane is made of LTA type zeolite.

11. A transient operation method according to claim 1 or 2, which is a start-up method.

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