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

[Technical Field]

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

[0002] A membrane separation method is known that uses 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 Literature 1). In a separation apparatus equipped with a separation membrane, heating of the separation membrane may be required when the apparatus is started up in order for the separation membrane to perform its intended function. In this case, efficient heating across the entire separation membrane is required. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] Development of a membrane-assisted membrane reactor, Mitsui Engineering & Shipbuilding Technical Report, February 2003, No. 178, 115-120. [Overview of the project] [Problems that the invention aims to solve]

[0004] The main object of the present invention is to provide a transient operation method for a separation apparatus equipped with a separation membrane, which enables efficient heating of the separation membrane. [Means for solving the problem]

[0005] [1] A transient operation method for a separation apparatus according to an embodiment of the present invention is a transient operation method for a separation apparatus comprising a separation membrane complex having a separation membrane and a substrate disposed on one side of the separation membrane, wherein the separation apparatus 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 substrate side of the separation membrane complex, and the method includes heating the separation membrane complex by supplying gas to at least the second flow path, wherein the gas supplied to the second flow path satisfies the following formula (1). ΔCp² / ΔT²<0(J / (mol·K) 2 ))···(1) ΔCp2: The difference between the constant-pressure molar specific heat a at the inlet of the separation membrane complex in the second channel and the constant-pressure molar specific heat b at the outlet of the separation membrane complex in the second channel (constant-pressure molar specific heat a - constant-pressure molar specific heat b) (unit: J / (mol·K)). ΔT2: The difference between the gas temperature a at the inlet of the separation membrane complex in the second channel and the gas temperature b at the outlet of the separation membrane complex in the second channel (gas temperature a - gas temperature b) (unit: K). [2] A transient operation method for a separation apparatus according to an embodiment of the present invention is a transient operation method for a separation apparatus comprising a separation membrane complex having a separation membrane and a substrate disposed on one side of the separation membrane, wherein the separation apparatus 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, the second flow path is located on the substrate side of the separation membrane complex, and the separation membrane complex is heated by supplying gas to the first flow path and the second flow path, wherein the ΔCp2 / ΔT2 of the gas supplied to the second flow path is smaller than the ΔCp1 / ΔT1 of the gas supplied to the first flow path, and ΔCp1 is equal to the constant-pressure molar specific heat c at the inlet of the separation membrane complex of the first flow path and the constant-pressure molar specific heat at the outlet of the separation membrane complex of the first flow path. The difference between the constant-pressure molar specific heat d and (constant-pressure molar specific heat c - constant-pressure molar specific heat d) (unit: J / (mol·K)) is ΔT1, the difference between the gas temperature c at the inlet of the separation membrane complex of the first flow path and the gas temperature d at the outlet of the separation membrane complex of the first flow path (gas temperature c - gas temperature d) (unit: K), the difference between the constant-pressure molar specific heat a at the inlet of the separation membrane complex of the second flow path and the constant-pressure molar specific heat b at the outlet of the separation membrane complex of the second flow path (constant-pressure molar specific heat a - constant-pressure molar specific heat b) (unit: J / (mol·K)), and the difference between the gas temperature a at the inlet of the separation membrane complex of the second flow path and the gas temperature b at the outlet of the separation membrane complex of the second flow path (gas temperature a - gas temperature b) (unit: K). [3] In the transient operation method of the separation apparatus described in [2] above, the gas supplied to the second flow path may satisfy the above formula (1). [4] In the transient operation method of the separation apparatus described in any of [1] to [3] above, the gas supplied to the second flow path may contain water vapor. [5] In the transient operation method of the separation apparatus described in [4] above, the water vapor content of the gas supplied to the second flow path may be 10 mol% or more. [6]~[8] In the transient operation method of the separation apparatus described in any of [1] to [5] above, the gas temperature at the inlet of the separation membrane composite of the second flow path may be 100°C or higher. [9] In the transient operation method of the separation apparatus described in any of [1] to [6] above, the separation membrane may be a zeolite membrane.

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

[11] The transient operation method described in any of the above "1" through

[10] may also be a startup method.

[12] The transient operation method described in any of the above "1" to

[10] may also be a stopping method. [Effects of the Invention]

[0006] According to embodiments of the present invention, a transient operation method for a separation apparatus equipped with a separation membrane can be provided, which enables efficient heating of the separation membrane. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a schematic diagram of a separation membrane complex used in a transient operation method for a separation apparatus according to one embodiment of the present invention. [Figure 2] Figure 2 is a schematic diagram of the separation membrane and substrate shown in Figure 1. [Figure 3] Figure 3 is a schematic diagram of one modified example of the separation membrane complex. [Figure 4] Figure 4 is a schematic cross-sectional view of the separation membrane composite shown in Figure 3. [Figure 5] Figure 5 is a schematic diagram of another modified example of the separation membrane complex. [Figure 6] Figure 6 is a schematic diagram illustrating the operation method of a separation device according to one embodiment of the present invention. [Modes for carrying out the invention]

[0008] Embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited to these embodiments. Furthermore, in order to clarify the explanation, the drawings may schematically represent the width, thickness, shape, etc., of each part compared to the embodiments; however, these are merely examples and do not limit the interpretation of the present invention.

[0009] A. Transient operation method of the separation device 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 transient operation method for a separation apparatus according to one embodiment of the present invention is a transient operation method for a separation apparatus 1 comprising a separation membrane complex 10 having a separation membrane 2 and a substrate 3 disposed on one side of the separation membrane 2. The separation apparatus 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 complex 10. More specifically, the first flow path 21 may be located on the separation membrane 2 side of the separation membrane complex 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 complex 10. More specifically, the second flow path 22 may be located on the substrate 3 side of the separation membrane complex 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 complex 10 may include any other suitable elements as long as the effects of the present invention are obtained. For example, the separation membrane 2 may be provided with a layer or powder that protects all or part of it, elements having a separation function such as another separation membrane, or another substrate (for example, a layer thinner than the substrate 3 and with the same composition as the substrate 3) located on the opposite side of the substrate 2 from the substrate 3. Also, part of the substrate 3 may be exposed.

[0011] The transient operation method for the separation device 1 described above comprises changing the temperature of the separation membrane composite 10 (i.e., heating or cooling the same) by at least supplying gas to the second flow path 22. Hereinafter, an embodiment in which the separation membrane composite 10 is heated will be described as a representative example. Further, the separation membrane composite 10 may be heated by gas supply to the first flow path 21.

[0012] In one embodiment, after the separation device 1 is started up by the above transient operation method, heating is continued until the separation membrane reaches a predetermined temperature (for example, a temperature at which the separation membrane can exert its separation function), and then the separation device shifts to steady operation. During steady operation, a fluid containing a substance that permeates through the separation membrane 2 (for example, a mixture containing water as a permeable substance and an organic compound that is difficult to permeate) is supplied to the first flow path 21. The substance that has permeated through the separation membrane 2 flows through the second flow path 22. By heating the separation membrane composite 10 via the above transient operation method, the separation membrane 2 can exhibit a predetermined separation performance (for example, separation performance based on permeability) during steady operation.

[0013] In one embodiment, the gas supplied to the second flow path 22 satisfies the following formula (1). ΔCp2 / ΔT2 < 0 (J / (mol·K 2 ))···(1) ΔCp2: the difference between the constant pressure molar specific heat a at the inlet of the separation membrane composite in the second flow path and the constant pressure molar specific heat b at the outlet of the separation membrane composite in the second flow path (constant pressure molar specific heat a - constant pressure molar specific heat b) (unit: J / (mol·K)) ΔT2: 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). ΔCp2 / ΔT2 is more preferably less than -0.004, and still more preferably less than -0.007. The lower limit of ΔCp2 / ΔT2 is, for example, -0.1.

[0014] In embodiments of the present invention, by setting ΔCp2 / ΔT2 (also called the temperature difference specific heat coefficient) within the above range, the separation membrane complex can be efficiently heated. More specifically, in the initial stages of heating, it is assumed that heat transfer from the gas is more likely to occur upstream of the separation membrane complex, 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 complex can be efficiently heated. In the prior art, a method of increasing the flow rate of the heating gas to promote heating downstream can be employed, but in that case, it becomes necessary to enlarge the blower and heating device of the peripheral equipment, and the increase in energy consumption becomes a problem. According to embodiments of the present invention, the separation membrane complex can be efficiently heated as described above while suppressing the flow rate of the heating gas. In other words, when considering the heat exchange between the heating gas and the object to be heated, the temperature difference heat capacity coefficient (unit: W / K) obtained by multiplying the temperature difference specific heat coefficient by the gas flow rate is used. 2 A major achievement of this embodiment of the present invention is the identification of the temperature difference specific heat coefficient as a key factor, rather than the other factors. ΔT2 is affected by the flow rate of the heating gas (ΔT2 becomes smaller at higher flow rates). In this embodiment of the present invention, the heating gas is identified by a characteristic value including ΔT2, and by controlling this characteristic value, the separation membrane composite can be heated appropriately and efficiently regardless of the gas flow rate.

[0015] In another embodiment, the ΔCp2 / ΔT2 of the gas supplied to the second flow path is smaller than the ΔCp1 / ΔT1 of the gas supplied to the first flow path. In this embodiment as well, ΔCp2 / ΔT2 can be within the above range (preferably less than 0, more preferably less than -0.004, and even more preferably less than -0.007). ΔCp1 is the difference between the constant-pressure molar specific heat c at the inlet of the separation membrane complex of the first channel and the constant-pressure molar specific heat d at the outlet of the separation membrane complex of the first channel (constant-pressure molar specific heat c - constant-pressure molar specific heat d) (unit: J / (mol·K)), and ΔT1 is the difference between the gas temperature c at the inlet of the separation membrane complex of the first channel and the gas temperature d at the outlet of the separation membrane complex of the first channel (gas temperature c - gas temperature d) (unit: K). 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 comprising a substrate and a separation membrane, the substrate 3 is generally configured to have a higher heat capacity than the separation membrane 2. Therefore, by specifying ΔCp1 / ΔT1 and ΔCp2 / ΔT2 as described above, it becomes possible to efficiently heat the separation membrane composite 10 (essentially the separation membrane 2).

[0017] The ΔCp1 / ΔT1 of the gas supplied to the first channel is, for example, 0 (J / (mol·K)). 2 ))~0.06(J / (mol·K 2 )) is.

[0018] In one embodiment, the gas temperature at the inlet of the separation membrane complex of the second channel is 100°C or higher. Preferably, the gas temperature at the inlet of the separation membrane complex of the second channel is 100°C to 300°C, and more preferably 130°C to 260°C. Within this range, the above 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. Of course, when heating at temperatures exceeding the above range, a gas containing water vapor may continue to be used. For example, the gas temperature at the inlet of the separation membrane complex of the first channel is 100°C to 300°C.

[0019] In one embodiment, the gas supplied to the second channel contains water vapor. The specific heat coefficient of the temperature difference can be controlled by the water vapor content. In one embodiment, the gas is supplied to the second channel 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 channel is less than the water vapor content of the gas supplied to the second channel. By using a highly humid gas as the gas supplied to the second channel, it becomes possible to efficiently heat the separation membrane complex (for example, it becomes possible to efficiently perform subsequent heating). In one embodiment, the gas is supplied to the first channel under conditions in which condensation does not occur on the separation membrane complex.

[0021] The water vapor content of the gas supplied to the second channel is preferably 10 mol% or more, and 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 channel is, for example, 100 mol%. In one embodiment, the water vapor partial pressure P(H2O) and saturated water vapor pressure P of the gas supplied to the second channel are sat (H2O) and [P(H2O) / P sat When the relationship [H2O] < 1 is met, the water vapor content of the gas supplied to the second channel is within the above range.

[0022] In one embodiment, the pressure in the first channel 21 and / or the second channel 22 is adjusted according to the ambient temperature in which the separation membrane complex 10 (substantially the separation membrane 2) is located. In the transient operation method of the 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 channel 21 is, for example, 0.1 MPaG to 20 MPaG. Furthermore, at the completion of startup 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 channel 21 is, for example, 0.1 MPaG to 20 MPaG.

[0023] In this specification, "transient operation method" is a concept that includes a start-up method and a stop-down method. Therefore, in the description of the embodiments above, "transient operation method" may be "start-up method" (i.e., "transient operation method" may be read as "start-up method") or "stop-down method". In this specification, "start-up method" is a method that includes heating the separation membrane. Also, "stop-down method" is a method that includes cooling the separation membrane.

[0024] B. Separation device B-1. Separation membrane complex As shown in Figure 1, the separation device 1 typically comprises a separation membrane complex 10 including a substrate 3 and a separation membrane 2. Although not shown, the separation membrane complex 10 is used in any suitable case. Typically, the separation membrane complex 10 extends in the same direction as the first flow path 21. The length of the separation membrane complex 10 can be arbitrarily and appropriately adjusted. In the separation membrane complex, the weight ratio of the substrate 3 to the separation membrane 2 (substrate / separation membrane) is, for example, 100 to 200,000. Also, 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. Base material 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 monolithic structure, comprising a three-dimensional network-like continuous skeleton and communicating pores defined by the skeleton. The substrate 3 may contain components that constitute the separation membrane 2.

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

[0027] Porous substrates can be composed of any suitable material. Typical materials for porous substrates include ceramic sintered bodies. Examples of ceramic sintered bodies include alumina, silica, mullite, zirconia, titania, yttria, silicon nitride, silicon carbide, and cordierite. Ceramic sintered bodies can be used alone or in combination.

[0028] The porous substrate may contain an inorganic binder. Examples of inorganic binders include titania, mullite, easily sintered alumina, silica, glass frit, clay minerals, and easily sintered cordierite. The inorganic binders can be used alone or in combination.

[0029] The porous substrate may consist of a single layer or 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 closer to the separation membrane 2.

[0030] The average pore size of the porous substrate is, for example, 0.01 μm to 70 μm, preferably 0.05 μm to 25 μm. The average pore size of the porous substrate on the separation membrane side is 0.01 μm to 1 μm, preferably 0.05 μm to 0.5 μm. Regarding the distribution of pore size 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 size of the porous substrate can be measured, for example, by a mercury porosimeter, palm porometer, or nanopalm porometer.

[0031] As shown in Figure 1, the base material 3 typically separates the first flow path 21 and the second flow path 22 described above. The base material 3 can take any suitable shape. Examples of the base material 3's shape include cylindrical, honeycomb, and flat plate shapes. In one embodiment, the base material 3 is a cylindrical base material 3a. Examples of cross-sectional shapes in the direction perpendicular to the longitudinal direction of the cylindrical base material 3a include triangles, quadrilaterals, pentagons, polygons with hexagons or more, circles, and ellipses, with a circle being preferred. The outer diameter and length of the cylindrical base material can be appropriately set depending on the purpose.

[0032] In the present embodiment, the internal space of the cylindrical base material 3a (the space defined by the inner circumferential surface of the cylindrical base material) includes one of the first flow path 21 and the second flow path 22, and the external space of the cylindrical base material 3a (the space outside the outer circumferential surface of the cylindrical base material) includes the other of the first flow path 21 and the second flow path 22. In the illustrated example, the internal space of the cylindrical base material 3a includes the first flow path 21, and the external space of the cylindrical base material 3a includes the second flow path 22.

[0033] In another embodiment, as shown in FIG. 3 and FIG. 4, the base material 3 is a honeycomb-shaped base material 3b. The honeycomb-shaped base material 3b includes 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-shaped base material 3b in the longitudinal direction.

[0034] The cells 34 extend from the first end face E1 (inflow end face) to the second end face E2 (outflow end face) of the honeycomb-shaped base material 3b in the longitudinal direction (axial direction) of the honeycomb-shaped base material 3b (see FIG. 4). The cells 34 have any appropriate shape in a cross section perpendicular to the longitudinal direction of the honeycomb-shaped base material 3b. Examples of the cross-sectional shape of the cells include triangles, quadrangles, pentagons, polygons having six or more sides, circles, and ellipses. All of the cells may have the same cross-sectional shape and size, or at least a part thereof may be different. Among such cross-sectional shapes of cells, a circle is preferable.

[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 a cross section perpendicular to the longitudinal direction of the honeycomb-shaped base material (that is, the number of cells 34 per unit area) can be appropriately set according to the purpose. The cell density is, for example, 4 cells / cm 2 to 320 cells / cm 2 The cell density may be within such a range, whereby sufficient strength and effective GSA (geometric surface area) of the honeycomb-shaped base material can be ensured.

[0036] The honeycomb substrate 3b has any suitable shape (overall shape). Examples of honeycomb substrate shapes include a cylindrical shape with a circular base, an elliptical columnar shape with an elliptical base, a prismatic columnar shape with a polygonal base, and a columnar shape with an irregular base. 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 multiple cells 34 (the space defined by the inner circumferential 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 3b (the space outside the outer circumferential 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 3b 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 channel 21 (see Figures 1 and 4) or the second channel 22 (see Figure 5).

[0039] In one embodiment, the separation membrane 2 faces the first channel 21. In Figure 1, the substrate 3 is a cylindrical substrate 3a, and the separation membrane 2 is formed on the inner surface of the cylindrical substrate 3a. In the illustrated example, the first channel 21 is formed in the portion of the cross-section of the separation membrane composite 10 where the separation membrane 2 is not formed (typically the central part). Furthermore, in Figure 4, the substrate 3 is a honeycomb-shaped substrate 3b, and the separation membrane 2 is formed on the inner surface of each of the multiple cells 34. The first channel 21 is formed in the portion of the cross-section of the cell 34 where the separation membrane 2 is not formed (typically the central part). The separation membrane 2 may be formed over the entire inner surface of the cylindrical substrate 3a or cell 34 (i.e., surrounding the first channel 21), as shown in the illustrated example, or it may be formed on a part of the inner surface of the cylindrical substrate 3a or cell 34. When the separation membrane is formed to surround the first channel, the separation efficiency can be improved.

[0040] Separation membrane 2 separates a specific substance from a mixture by, for example, utilizing differences in molecular size and / or adsorption properties.

[0041] The separation membrane 2 can be composed of any suitable material. Typical materials for the separation membrane 2 include inorganic materials. Examples of inorganic materials include zeolite, silica, and carbon. Inorganic materials can be used alone or in combination. The specific heat of the materials constituting 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 for the separation membrane 2. In one embodiment, the separation membrane 2 is a zeolite membrane.

[0043] A zeolite film is constructed by forming a zeolite film on the surface of a substrate. The zeolite film may contain two or more types of zeolites with different structures and compositions.

[0044] Examples of zeolites that make up a zeolite film include those in which the central atom (T atom) of the oxygen tetrahedron (TO4) constituting the zeolite is solely Si, or composed of Si and Al; AlPO-type zeolites in which the T atom is composed of Al and P; SAPO-type zeolites in which the T atom is composed of Si, Al and P; MAPSO-type zeolites in which the T atom is composed of magnesium (Mg), Si, Al and P; and ZnAPSO-type zeolites in which the T atom is composed of zinc (Zn), Si, Al and P. Some of the T atoms may be substituted with other elements.

[0045] Examples of the above-mentioned zeolites include 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, and SOD type zeolites. Among these zeolites, LTA-type zeolites are a notable example.

[0046] The maximum number of member rings in a 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 film contains SiO2 and Al2O3. The zeolite film may further contain alkali metals. The alkali metals are, for example, sodium (Na) or potassium (K).

[0048] The molar ratio of SiO2 / Al2O3 in the zeolite film is, for example, 100 or less, preferably 10 or less, and more preferably 5 or less. The lower limit of the molar ratio of SiO2 / Al2O3 in the zeolite film is typically 2. The molar ratio of SiO2 / Al2O3 can be measured, for example, by scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX; X-ray acceleration voltage 10kV).

[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, 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. If the separation membrane 2 is a zeolite membrane, the average pore size is defined as the arithmetic mean of the short and long axes of the n-membered ring pores, where n is the maximum number of member rings in the zeolite. An n-membered ring pore is a pore where the number of oxygen atoms in the ring structure formed by oxygen atoms bonded to T atoms is n. If there are multiple n-membered ring pores with equal n, the average pore size of the zeolite is defined as the arithmetic mean of the short and long axes of all n-membered ring pores. The average pore size of a zeolite membrane is determined by the skeletal structure of the zeolite, and can be found in the International Zeolite Society's "Database of Zeolite Structures" [online], or via the Internet.<URL:http: / / www.iza-structure.org / databases / > It can be determined from the values ​​disclosed.

[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. Increasing the thickness of the separation membrane increases selectivity. Increasing the thickness of the separation membrane increases the 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 suitable method depending on the material constituting the membrane. For example, a zeolite membrane can be formed using zeolite as a seed crystal. Base material Zeolite can be obtained by coating a substrate with seed crystals attached, immersing the substrate in a raw material solution, and growing zeolite using the seed crystals as nuclei through hydrothermal synthesis. The raw material solution includes, for example, a silica source, an alumina source, organic matter, an alkali source, and water. The heating temperature in hydrothermal synthesis is, for example, 60°C to 200°C. The heating time is, for example, 1 hour to 240 hours. Alternatively, a separation membrane may be formed using a raw material slurry obtained by mixing an organic binder, ceramic raw materials, and a solvent.

[0053] B-2. Other components The separation apparatus 1 described above may include any suitable elements in addition to the separation membrane complex 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, and a recovery unit for recovering the fluids after they have passed through the separation membrane complex. Examples of heating devices include reactors involving chemical reactions, heaters, and heat exchangers. The separation apparatus 1 may further include a pressure adjustment unit 7 capable of adjusting the pressure in the first flow path 21 and / or the second flow path 22 in the separation membrane complex 10. The separation apparatus 1 may further include a control unit 8 capable of controlling the operation of the separation apparatus 1. Components of the separation apparatus other than the separation membrane complex are described, for example, in International Publication No. 2018 / 225325. The description in said publication is incorporated herein by reference.

[0054] In one embodiment, as shown in Figure 6, the separation apparatus 1 further comprises, in addition to the separation membrane complex 10, a supply unit 4 for supplying a mixture to the first channel 21 of the separation membrane complex 10; a first recovery unit 5 for recovering the fluid that has passed through the first channel 21; and a second recovery unit 6 for recovering the permeate material that has permeated through the separation membrane 2. The illustrated separation apparatus 1 is configured to allow adjustment of the temperature, pressure, and flow rate of the mixture passing through the first channel. Note that Figure 6 illustrates one embodiment of the present invention, and the present invention is not limited thereto.

[0055] The illustrated supply unit 4 is capable of adjusting the temperature and flow rate of the mixture supplied (flowing into) the first flow path 21. The supply unit 4 comprises a supply line 41, a heating device 42, and a flow rate regulator 43. The supply line 41 is a pipe for supplying the mixture to the first channel 21. The upstream end of the supply line 41 in the direction of mixture supply is connected to a storage tank for storing the mixture, although this is not shown in the diagram. The downstream end of the supply line 41 in the direction of mixture supply is connected to the inlet of the first channel 21 of the separation membrane complex 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 can employ any suitable configuration. The flow regulator 43 can adjust the flow rate of the mixture through the supply line 41. The flow regulator 43 can employ any suitable configuration. In the illustrated example, the flow regulator 43 is located in the supply line 41 between the heating device 42 and the separation membrane complex 10. The supply unit 4 may include other equipment as needed. For example, other equipment may be present between the flow regulator 43 and the separation membrane complex 10 in the supply line 41.

[0056] The first recovery unit 5 in the illustrated example is capable of adjusting the pressure in the first flow path 21. The first recovery unit 5 comprises a first recovery line 51 and a pressure regulating valve 52. The first recovery line 51 is a pipe through which the fluid that has passed through the first channel 21 of the separation membrane complex 10 passes. The upstream end of the first recovery line 51 in the direction of fluid passage is connected to the outlet of the first channel 21 of the separation membrane complex 10. The downstream end of the first recovery line 51 in the direction of fluid passage is connected to a storage tank, for example, although not shown in the figure. The pressure regulating valve 52 is located in the first recovery line 51. The pressure regulating valve 52 can adjust the opening degree of the first recovery line 51, and thereby adjust the pressure in the first flow path 21.

[0057] The second recovery unit 6 in the illustrated example includes a second recovery line 61. The second recovery line 61 is a pipe through which the fluid that has passed through the second flow path 22 of the separation membrane complex 10 passes. The upstream end of the second recovery line 61 in the direction of fluid passage is connected to the outlet of the second flow path 22 of the separation membrane complex 10. The downstream end of the second recovery line 61 in the direction of fluid passage is connected to a storage tank, for example, although not shown in the figure.

[0058] In the embodiment described above, the supply unit 4 upstream of the separation membrane complex 10 adjusts the temperature and flow rate of the mixture supplied (flowing into) the first channel 21, and the first recovery unit 5 downstream of the separation membrane complex 10 adjusts the pressure of the mixture in the first channel 21. However, the configuration of the separation apparatus 1 is not limited to this. The supply unit 4 may be configured to adjust the pressure of the mixture in the first channel 21. Also, the first recovery unit 5 may be configured to adjust the flow rate of the mixture passing through the first channel 21. [Industrial applicability]

[0059] The transient operation method of the separation apparatus according to the embodiment of the present invention can be used for the separation of a specific substance in a mixture, and can be particularly suitably used for the separation of water from a water-containing mixture. [Explanation of symbols]

[0060] 1 Separation device 2 Separation membrane 3 Base material 21 First channel 22 Second channel

Claims

1. A transient operation method for 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 membrane complex has an inlet and an outlet, The separation device has a first channel and a second channel, the first channel being located on the separation membrane side of the separation membrane complex, and the second channel being located on the substrate side of the separation membrane complex. This includes heating the separation membrane complex by supplying gas to the second channel, A transient operation method for a separation apparatus, 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 : The difference between the constant-pressure molar specific heat a of the separation membrane complex in the second channel at the inlet and the constant-pressure molar specific heat b of the separation membrane complex in the second channel at the outlet (constant-pressure molar specific heat a - constant-pressure molar specific heat b) (unit: J / (mol·K)), ΔT ２ : The difference between the gas temperature a at the inlet of the separation membrane complex of the second channel and the gas temperature b at the outlet of the separation membrane complex of the second channel (gas temperature a - gas temperature b) (unit: K).

2. A transient operation method for 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 membrane complex has an inlet and an outlet, The separation device has a first channel and a second channel, the first channel being located on the separation membrane side of the separation membrane complex, and the second channel being located on the substrate side of the separation membrane complex. This includes heating the separation membrane complex by supplying gas to the first and second channels, ΔCp of the gas supplied to the second flow path ２ / ΔT ２ is smaller than ΔCp of the gas supplied to the first flow path １ / ΔT １ ​ The ΔCp １ This is the difference between the constant-pressure molar specific heat c at the inlet of the separation membrane complex in the first channel and the constant-pressure molar specific heat d at the outlet of the separation membrane complex in the first channel (constant-pressure molar specific heat c - constant-pressure molar specific heat d) (unit: J / (mol·K)), The ΔT １ This is the difference (gas temperature c - gas temperature d) (unit: K) between the gas temperature c at the inlet of the separation membrane complex of the first flow path and the gas temperature d at the outlet of the separation membrane complex of the first flow path. The ΔCp ２ This is the difference between the constant-pressure molar specific heat a of the separation membrane complex in the second channel at the inlet and the constant-pressure molar specific heat b of the separation membrane complex in the second channel at the outlet (constant-pressure molar specific heat a - constant-pressure molar specific heat b) (unit: J / (mol·K)), The ΔT ２ This is the difference (gas temperature a - gas temperature b) (unit: K) between the gas temperature a at the inlet of the separation membrane complex of the second flow path and the gas temperature b at the outlet of the separation membrane complex of the second flow path. Transient operation method for a separation device.

3. A transient operation method for the 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. A transient operation method for a separation apparatus according to claim 1 or 2, wherein the gas supplied to the second flow path includes water vapor.

5. A transient operation method for 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. A 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 of the second flow path is 100°C or higher.

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

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

9. A 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. A transient operation method for a separation apparatus according to claim 9, wherein the zeolite membrane is composed of LTA-type zeolite.

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

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

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