Method for operating a separation device

Abstract

Provided is a method for operating a separation device capable of suppressing breakage of a separation membrane. A method for operating a separation device according to an embodiment of the present invention is a method for operating a separation device having a separation membrane, the separation device comprising: a first flow path to which a mixture containing an adsorbent adsorbed on the separation membrane is supplied; and a second flow path through which the substance that has passed through the separation membrane flows. The method for operating the separation device includes a step for supplying the mixture to the first flow path such that the adsorbent concentration distribution in the direction in which the mixture passes is greater than 0 and 0.3 or less.

Description

TECHNICAL FIELD

[0001] The present application relates to a method for operating a separation apparatus. BACKGROUND

[0002] A membrane separation method is known, which separates a specific substance from a mixture using a difference in adsorption properties with respect to a separation membrane. As such a membrane separation method, for example, a dehydration method using an LTA-type zeolite membrane is proposed (see Non-Patent Literature 1). In the dehydration method described in Non-Patent Literature 1, a mixture heated to a prescribed adsorption temperature is supplied to the LTA-type zeolite membrane, whereby a specific substance is adsorbed to the LTA-type zeolite membrane and separated from the mixture. However, in the dehydration method described in Non-Patent Literature 1, in the separation process of the specific substance, particularly, in the process of warming the LTA-type zeolite membrane to the adsorption temperature and the process of cooling the LTA-type zeolite membrane from the adsorption temperature to room temperature, damage such as cracking occurs in the LTA-type zeolite membrane.

[0003] PRIOR ART DOCUMENTS

[0004] NON-PATENT LITERATURE

[0005] Non-Patent Literature 1: Development of Membrane-Assisted Membrane Reactor, Mitsubishi Heavy Industries Technical Report, February 2003, No. 178, 115-120 SUMMARY

[0006] The present application relates to a method for operating a separation apparatus.

[0007] [1] The method for operating a separation apparatus according to an embodiment of the present application is a method for operating a separation apparatus having a separation membrane. The separation apparatus has a first flow path and a second flow path. A mixture containing an adsorbed substance adsorbed to the separation membrane is supplied to the first flow path. A substance that has permeated through the separation membrane is caused to flow through the second flow path. The method for operating the separation apparatus includes a step of supplying the mixture to the first flow path in such a manner that the concentration distribution of the adsorbed substance in the passage direction of the mixture exceeds 0 and is 0.3 or less.

[0008] [2] The method for operating a separation apparatus according to the above [1], wherein the adsorbed substance is water.

[0009] [3] The method for operating a separation apparatus according to the above [2], wherein the mixture contains water and an organic compound.

[0010] [4] The method for operating a separation apparatus according to any one of the above [1] to [3], wherein, in the step of supplying the mixture to the first flow path, the average Reynolds number of the mixture flowing through the first flow path is adjusted to 2000 or more.

[0011] [5] The operation method of the separation apparatus according to any one of [1] to [4], wherein the separation membrane is a zeolite membrane.

[0012] [6] The operation method of the separation apparatus according to [5], wherein a molar ratio of Si02 / Al203 in the zeolite membrane is less than 5.

[0013] [7] The operation method of the separation apparatus according to any one of [1] to [6], wherein, in the step of feeding the mixture to the first flow path, the temperature of the fed mixture is increased and / or the pressure in the first flow path is increased.

[0014] [8] The operation method of the separation apparatus according to any one of [1] to [6], wherein, in the step of feeding the mixture to the first flow path, the pressure in the first flow path is decreased, and then the temperature of the fed mixture is decreased.

[0015] [9] The operation method of the separation apparatus according to any one of [1] to [8] is a transition operation.

[0016] Effects of Invention

[0017] According to the embodiment of the present application, an operation method of a separation apparatus capable of suppressing breakage of a separation membrane can be realized. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is a schematic configuration view of a separation membrane composite used in an operation method of a separation apparatus according to an embodiment of the present application.

[0019] Figure 2 is a schematic configuration view of a separation membrane and a substrate of Figure 1

[0020] Figure 3 is a schematic configuration view of a variation of a separation membrane composite.

[0021] Figure 4 is a schematic cross-sectional view of a separation membrane composite of Figure 3

[0022] Figure 5 is a schematic configuration view of another variation of a separation membrane composite.

[0023] Figure 6 is a schematic view for explaining an operation method of a separation apparatus according to an embodiment of the present application. DETAILED DESCRIPTION

[0024] ​​Hereinafter, embodiments of the present application will be described with reference to the accompanying drawings. However, the present application is not limited to these embodiments. In addition, the drawings make the description clearer, and thus the width, thickness, shape, and the like of each portion are sometimes schematically shown in comparison with the embodiments, but are only one example and do not limit the explanation of the present application.

[0025] A. Outline of the operation method of the separation device

[0026] Figure 1 is a schematic configuration diagram of a separation membrane complex used in the operation method of the separation device according to one embodiment of the present application, Figure 2 is a schematic configuration diagram of the separation membrane and the base material of Figure 1 .

[0027] The operation method of the separation device according to one embodiment of the present application is an operation method of a separation device 1 having a separation membrane 2, in which a specific adsorbent substance can be separated from a mixture by using a difference in adsorption properties with respect to the separation membrane 2. The separation device 1 has a first flow path 21 and a second flow path 22. The mixture containing the adsorbent substance adsorbed to the separation membrane 2 is supplied to the first flow path 21. The substance having permeated the separation membrane 2 is supplied to the second flow path 22. The operation method of such a separation device 1 includes a step of supplying the mixture to the first flow path 21 in such a manner that the adsorbent substance concentration distribution in the passing direction of the mixture exceeds 0 and is 0.3 or less.

[0028] The inventors of the present application have found that the adsorbent substance concentration distribution of the mixture passing through the first flow path of the separation device has an influence on the breakage of the separation membrane, and thus have completed the present application. In the embodiment of the present application, the mixture is supplied to the first flow path in such a manner that the adsorbent substance concentration distribution in the passing direction of the mixture exceeds 0 and is 0.3 or less.

[0029] If the adsorbent substance concentration distribution exceeds the upper limit described above, the degree of volume expansion (or reduction) of the separation membrane differs in the passing direction of the mixture, and thus stress can be generated in the separation membrane, which can cause breakage of the separation membrane. In view of this, in one embodiment of the present application, since the adsorbent substance concentration distribution is the upper limit or less, the uniformity of the degree of volume expansion (or reduction) of the separation membrane in the passing direction of the mixture can be improved, and as a result, the stress generated in the separation membrane can be reduced. Thus, the breakage (typically, cracking) of the separation membrane can be suppressed, and the adsorbent substance can be adsorbed to the separation membrane and separated from the mixture flowing in the first flow path.

[0030] The smaller the adsorbent concentration distribution in the passing direction of the mixture is, the more desirable it is. The adsorbent concentration distribution in the passing direction of the mixture is more preferably 0.25 or less. Thus, even in a local portion where the measurement of the adsorbent concentration distribution is substantially difficult, the adsorbent concentration distribution can be made 0.3 or less, and thus the breakage of the separation membrane can be suppressed.

[0031] The lower limit of the adsorbent concentration distribution in the passing direction of the mixture is not particularly limited, and is typically 0.002 from the viewpoint of the analysis accuracy.

[0032] It should be noted that the adsorbent concentration distribution can be calculated by the following formula (1).

[0033] Adsorbent concentration distribution = (P in / P ＊ in - P out / P ＊out ) / L... (1)

[0034] (In formula (1), P in represents the partial pressure (kPa) of the adsorbent in the mixture flowing into the first flow path; P ＊ in represents the saturated vapor pressure (kPa) of the adsorbent at the temperature of the mixture flowing into the first flow path; P out represents the partial pressure (kPa) of the adsorbent in the mixture flowing out of the first flow path; P ＊out represents the saturated vapor pressure (kPa) of the adsorbent at the temperature of the mixture flowing out of the first flow path; and L represents the length (unit: m) of the first flow path.)

[0035] It should be noted that the partial pressure of the adsorbent in the mixture can be measured by any appropriate method corresponding to the adsorbent.

[0036] The separation membrane 2 adsorbs the adsorbent contained in the mixture passing through the first flow path 21. The separation membrane 2 can allow the adsorbent to pass therethrough so that the adsorbent flows into the second flow path 22, or can retain the adsorbent. The proportion of the adsorbent contained in the fluid (mixture in which the adsorbent is reduced) that has passed through the first flow path 21 is lower than the proportion of the adsorbent contained in the mixture before being supplied to the first flow path 21.

[0037] The length of the first flow path 21 is, for example, 5 cm to 150 cm, and is preferably 15 cm to 100 cm.

[0038] In one embodiment, in the process of supplying the mixture to the first flow path 21, the average Reynolds number of the mixture flowing through the first flow path 21 is adjusted to, for example, 2000 or more, preferably 2500 or more, and more preferably 4000 or more. By making the average Reynolds number 2500 or more, it is possible to reduce the cost without excessively pursuing the accuracy of the measuring equipment. In addition, by making the Reynolds number 4000 or more, it is not necessary to change the operating conditions even if the influence of the surface roughness of the membrane is present, and thus it is preferable. That is, typically, the mixture passes through the first flow path 21 in a turbulent flow. If the average Reynolds number of the mixture flowing through the first flow path is the above lower limit or more, the concentration at the surface of the separation membrane in the mixture flowing through the first flow path is uniformized by the stirring action of the turbulent flow, and it is possible to stably adjust the adsorbent concentration distribution to the above upper limit or less. Note that the upper limit of the average Reynolds number of the mixture flowing through the first flow path is typically 500,000, but is not limited thereto if the pressure loss or resonance does not constitute a problem.

[0039] Note that, in the present specification, the "average Reynolds number of the mixture flowing through the first flow path" means the average of the Reynolds number (Re) of the mixture at the upstream end portion (inlet) of the first flow path and the Reynolds number (Re) of the mixture at the downstream end portion (outlet) of the first flow path. The Re of the mixture is calculated based on the following formula (2).

[0040] Re = (p x v x L) / μ... (2)

[0041] (In formula (2), p represents the density of the mixture [unit: kg / m 3 ]; v represents the flow rate of the mixture [unit: m / s]; L represents the representative length of the first flow path [unit: m]; and μ represents the viscosity coefficient of the mixture [unit: Pa-s]). The representative length of the first flow path is, for example, the inner diameter of the first flow path.

[0042] Note that the viscosity coefficient of the mixture can be calculated using, for example, the measurement method given in JIS Z 8803 or a calculation method based on the kinetic theory of gases.

[0043] In one embodiment, the Reynolds number of the mixture flowing through the portion of the first flow path 21 between the upstream end portion (inlet) and the downstream end portion (outlet) is, for example, 2000 or more, preferably 2500 or more, and more preferably 4000 or more, and is, for example, 500,000 or less. If the Reynolds number of the mixture flowing through the portion of the first flow path between the upstream end portion (inlet) and the downstream end portion (outlet) is the above lower limit or more, it is possible to more stably adjust the adsorbent concentration distribution of the mixture flowing through the first flow path to the above upper limit or less.

[0044] The adsorbent with respect to the separation membrane 2 refers to a substance that satisfies the following formula (3). C = (p x v) / (R x T)... (3)

[0045] |B-A| / A×100>0···(3)

[0046] (In equation (3), A represents the relative pressure P / P at room temperature (23℃). ＊ The volume per unit mass of the separation membrane when exposed to an atmosphere of 0 until equilibrium is reached (e.g., 1 hour); B represents the volume per unit mass of the separation membrane at room temperature (23°C) under relative pressure P / P. ＊ The volume per unit mass of the separation membrane when exposed to an adsorbent atmosphere of 0.5 until equilibrium is reached (e.g., 1 hour). Here, P represents the pressure of the adsorbent under the stated atmosphere. ＊ This represents the saturated vapor pressure of the adsorbed substance at room temperature.

[0047] It should be noted that there is no particular limitation on the method for calculating the volume per unit mass of the separation membrane. For example, a sample of the same mass as the separation membrane can be prepared, and its density can be measured under an adsorbent atmosphere to obtain the volume per unit mass of the separation membrane. In particular, when the separation membrane is a crystalline material, the volume per unit mass of the crystal lattice under an adsorbent atmosphere can be measured using methods such as X-ray diffraction to obtain the volume per unit mass of the separation membrane.

[0048] The adsorbent preferably satisfies the following formula (4), and even more preferably satisfies the following formula (5), and further preferably satisfies the following formula (6).

[0049] |B-A| / A×100≥0.3···(4)

[0050] (B-A) / A×100>0···(5)

[0051] (B-A) / A×100>0.3···(6)

[0052] (In equations (4) to (6), A and B represent the same A and B as in equation (3) above.)

[0053] When the adsorbed substance satisfies at least one of the above formulas (4) to (6), for example, the difference in thermal expansion between the adsorbed substance and the support increases further at high temperatures. Therefore, the operation method of the separation device according to one embodiment of the present invention is particularly effective.

[0054] The mixture (supply gas) may contain one adsorbent or two or more adsorbents. In this case, it is preferable that any one or more of the adsorbents satisfy the above formula (4).

[0055] Specifically, examples of adsorbents include: water, CO2, NH3, and primary alcohols.

[0056] In one embodiment, the adsorbing substance includes water. If the adsorbing substance includes water, the breakage of the separation membrane can be more stably suppressed. Typically, water can permeate through the separation membrane 2 and flow into the second flow path 22. Note that the water vapor partial pressure in the mixture can be measured, for example, by condensing the mixture and analyzing it using liquid chromatography, or by using a dew point meter.

[0057] The mixture supplied to the first flow path 21 can include a non-adsorbing substance other than the adsorbing substance described above. That is, the non-adsorbing substance is, for example, a substance that does not satisfy the above formula (3) (i.e., |B-A| / A x 100 = 0), or a substance that does not satisfy the above formula (4) (i.e., |B-A| / A x 100 < 0.3), or a substance that does not satisfy the above formula (5) (i.e., (B-A) / A x 100 = 0), or a substance that does not satisfy the above formula (6) (i.e., (B-A) / A x 100 = 0.3). Note that, from the viewpoint of significant figures, |B-A| / A x 100 = 0 includes the case where |B-A| / A x 100 is less than 0.01.

[0058] The non-adsorbing substance is substantially not adsorbed to the separation membrane 2 and passes through the first flow path 21. Therefore, the proportion of the non-adsorbing substance in the fluid (mixture in which the adsorbing substance has been reduced) that has passed through the first flow path 21 is higher than the proportion of the non-adsorbing substance in the mixture before being supplied to the first flow path 21.

[0059] As the non-adsorbing substance, typically, an organic compound can be given. In one embodiment, the mixture supplied to the first flow path 21 is an aqueous organic compound including water and an organic compound.

[0060] As the organic compound, for example, alcohols such as methanol, ethanol, isopropanol, and the like; ketones such as acetone, ethyl methyl ketone, and the like; carboxylic acids such as formic acid, acetic acid, butyric acid, propionic acid, benzoic acid, and the like; aromatic hydrocarbons such as toluene, benzene, and the like; phenols such as phenol, and the like; aldehydes; ethers; esters; amines; nitriles; straight-chain saturated hydrocarbons; branched-chain saturated hydrocarbons; cyclic saturated hydrocarbons; chain unsaturated hydrocarbons; nitrogen-containing compounds; sulfur-containing compounds; halogen derivatives of hydrocarbons can be given. The organic compound can be contained alone in the mixture or two or more kinds thereof can be combined and contained in the mixture.

[0061] In addition, the mixture is not particularly limited and can include a purge gas in addition to the adsorbing substance described above and the non-adsorbing substance described above. As the purge gas, for example, nitrogen, air, and the like can be given. The purge gas can be used alone or in combination.

[0062] Such a mixture can be a gas or a liquid when supplied to the first flow path 21. The mixture is preferably supplied to the first flow path 21 in a gaseous state.

[0063] The temperature of the mixture supplied to the first flow path 21 is, for example, 100°C to 350°C. The pressure (gauge pressure) within the first flow path 21 is, for example, 0.1 MPaG to 20 MPaG.

[0064] In addition, in the second flow path 22, at least the substance that has permeated through the separation membrane 2 (hereinafter also referred to as the permeate) flows through. Examples of permeate include the adsorbed substance mentioned above and the purge gas. In addition to the permeate, the purge gas mentioned above may also flow through the second flow path 22.

[0065] The pressure (gauge pressure) within the second flow path 22 is, for example, -0.1 MPaG to 0.1 MPaG, preferably below -0.09 MPaG. If the pressure within the second flow path 22 is negative, the permeable material can flow smoothly through the second flow path without the use of purging gas.

[0066] The following is a detailed description of the separation device.

[0067] B. Separation device

[0068] B-1. Separation Membrane Complex

[0069] like Figure 1 As shown, the separation device 1 typically includes a separation membrane composite 10 comprising a substrate 3 and a separation membrane 2. Although not shown, the separation membrane composite 10 is housed in any suitable housing for use. Typically, the separation membrane composite 10 extends in the same direction as the first flow path. The length of the separation membrane composite 10 can be arbitrarily and appropriately adjusted.

[0070] B-1-1. Substrate

[0071] The substrate 3 supports the separation membrane 2. In one embodiment, the substrate 3 is a porous substrate. The porous substrate, for example, has an integral structure comprising: a three-dimensional mesh-like continuous framework and interconnecting pores defined by the framework.

[0072] The porous substrate can be composed of any suitable material. Representative examples of porous substrate materials include sintered ceramic bodies. Examples of sintered ceramic bodies include: alumina, silica, andalusite, zirconium oxide, titanium dioxide, yttrium oxide, silicon nitride, silicon carbide, and cordierite. Sintered ceramic bodies can be used alone or in combination. Alumina is preferably used in sintered ceramic bodies.

[0073] Porous substrates may contain inorganic binders. Examples of inorganic binders include: titanium dioxide, andalusite, easily sinterable alumina, silica, glass frit, clay minerals, and easily sinterable cordierite. Inorganic binders can be used alone or in combination.

[0074] The porous base material can be composed of a single layer, or can have a multi-layer structure in which a plurality of layers are stacked. In one embodiment, as shown in Figure 2 the porous base material has a multi-layer structure having a plurality of layers having different pore diameters. In this case, it is preferable that the closer to the separation membrane 2, the smaller the pore diameter.

[0075] The average pore diameter of the porous base material is, for example, 0.01 μm to 70 μm, and preferably 0.05 μm to 25 μm. The average pore diameter of the porous base material on the separation membrane side is 0.01 μm to 1 μm, and preferably 0.05 μm to 0.5 μm. As for the distribution of the pore diameters of the entire porous base material including the surface and the inside, 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 base material on the separation membrane side is, for example, 25% to 50%. The average pore diameter of the porous base material can be measured using, for example, a mercury porosimeter, a pore size distribution measuring device, or a nano-size pore size distribution measuring device.

[0076] As shown in Figure 1 , typically, the base material 3 separates the above-described first flow path 21 and the above-described second flow path 22. The base material 3 can adopt any appropriate shape. As the shape of the base material 3, for example, a cylindrical shape, a honeycomb shape, and a flat plate shape can be given.

[0077] In one embodiment, the base material 3 is a cylindrical base material 3a. As the cross-sectional shape of the cylindrical base material 3a in a direction orthogonal to the length direction, for example, a triangle, a quadrangle, a pentagon, a hexagon or more, a circle, and an ellipse can be given, and preferably a circle can be given. The outer diameter and the length of the cylindrical base material can be appropriately set according to the purpose.

[0078] In the present embodiment, the inner space of the cylindrical base material 3a (the space defined by the inner peripheral surface of the cylindrical base material) includes any one of the first flow path 21 and the second flow path 22, and the outer space of the cylindrical base material 3a (the space outside the outer peripheral 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 inner space of the cylindrical base material 3a includes the first flow path 21, and the outer space of the cylindrical base material 3a includes the second flow path 22.

[0079] In another embodiment, as shown in Figure 3 and Figure 4 , the base material 3 is a honeycomb-shaped base material 3b. The honeycomb-shaped base material 3b has a partition wall 33 that defines 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 length direction.

[0080] The cells 34 extend from the first end surface El (inflow end surface) to the second end surface E2 (outflow end surface) of the honeycomb base material 3b in the length direction (axis direction) of the honeycomb base material 3b (see Figure 4 ). The cells 34 have an arbitrary appropriate shape in a cross section of the honeycomb base material 3b in a direction orthogonal to the length direction. As the cross-sectional shape of the cells, for example, a triangle, a quadrangle, a pentagon, a hexagon or more, a circle, an ellipse can be cited. As for the cross-sectional shape and size of the cells, all can be the same, or at least a part can be different. Among such cross-sectional shapes of the cells, a circle is preferable.

[0081] The distance between the central axes of the plurality of cells 34 is, for example, 0.3 mm to 20 mm. The cell density (i.e., the number of cells 34 per unit area) in a cross section of the honeycomb base material in a direction orthogonal to the length direction can be appropriately set according to the purpose. The cell density can be, for example, 0.5 cells / cm 2 to 320 cells / cm 2 If the cell density is in such a range, the strength and effective GSA (geometric surface area) of the honeycomb base material can be sufficiently ensured.

[0082] The honeycomb base material 3b has an arbitrary appropriate shape (overall shape). As the shape of the honeycomb base material, for example, a circular cylinder in which the bottom surface is circular, an elliptical cylinder in which the bottom surface is elliptical, a prism in which the bottom surface is polygonal, a column in which the bottom surface is irregular can be cited. The honeycomb base material 3b of the illustrated example has a cylindrical shape. The outer diameter and length of the honeycomb base material can be appropriately set according to the purpose.

[0083] In the present embodiment, the internal space of each of the plurality of cells 34 (space defined by the inner peripheral surface of the cell) includes any one of the first flow path 21 and the second flow path 22, and the external space of the honeycomb base material 3b (space outside the outer peripheral surface of the honeycomb 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 cell 34 includes the first flow path 21, and the external space of the honeycomb base material 3b includes the second flow path 22.

[0084] B-1-2. Separation membrane

[0085] The separation membrane 2 is typically provided directly on the surface of the base material 3. The separation membrane 2 can face the first flow path 21 (see Figure 1 and Figure 4 ), or can face the second flow path 22 (see Figure 5). If the separation membrane faces the first flow path, the adsorbing substance contained in the mixture passing through the first flow path directly contacts the separation membrane. Therefore, the separation membrane can adsorb the adsorbing substance with high efficiency. If the separation membrane faces the second flow path, the adsorbing substance contained in the mixture passing through the first flow path permeates the base material to reach the separation membrane. Thus, the separation membrane can also adsorb the adsorbing substance.

[0086] In one embodiment, the separation membrane 2 faces the first flow path 21.

[0087] Figure 1 In this case, the base material 3 is a cylindrical base material 3a, and the separation membrane 2 is formed on the inner surface of the cylindrical base material 3a. In the illustrated example, the portion (typically, the central portion) in the cross section of the separation membrane composite 10 in which the separation membrane 2 is not formed is formed with the first flow path 21.

[0088] In addition, Figure 4 In this case, the base material 3 is a honeycomb base material 3b, and the separation membrane 2 is formed on the inner surface of each of the plurality of cells 34. The portion (typically, the central portion) in the cross section of the cell 34 in which the separation membrane 2 is not formed is formed with the first flow path 21.

[0089] The separation membrane 2 can be formed on the entire inner surface of the cylindrical base material 3a or the cell 34 (i.e., surround the first flow path 21) as in the illustrated example, or can be formed on a portion of the inner surface of the cylindrical base material 3a or the cell 34. If the separation membrane is formed to surround the first flow path, the separation efficiency of the adsorbing substance can be improved.

[0090] Typically, the separation membrane 2 has fine pores. The separation membrane 2 separates a specific substance from a mixture by allowing the specific substance to permeate using, for example, a difference in molecular size and / or a difference in adsorptivity.

[0091] The separation membrane 2 can be composed of any appropriate material. As the material of the separation membrane 2, for example, zeolite, alumina, titania, silica, zirconia, mullite, and carbon can be cited. The membrane material can be used alone or in combination.

[0092] In the case where the adsorbing substance contains water, as the material of the separation membrane 2, zeolite is preferably cited. In one embodiment, the separation membrane 2 is a zeolite membrane. If the separation membrane is a zeolite membrane, water can be stably adsorbed.

[0093] A zeolite membrane is composed of a zeolite formed in a film shape on the surface of a base material. The zeolite membrane can contain two or more kinds of zeolites different in structure or composition.

[0094] As the zeolite constituting the zeolite membrane, for example, there can be mentioned a zeolite in which the atom (T atom) at the center of the oxygen tetrahedron (TO4) constituting the zeolite is only Si, a zeolite in which the T atom includes Si and Al, an AlPO type zeolite in which the T atom includes Al and P, an SAPO type zeolite in which the T atom includes Si, Al and P, a MAPSO type zeolite in which the T atom includes magnesium (Mg), Si, Al and P, and a ZnAPSO type zeolite in which the T atom includes zinc (Zn), Si, Al and P. A part of the T atom can be substituted with another element.

[0095] As the above zeolite, for example, there can be mentioned a zeolite of AEI type, AEN type, AFN type, AFV type, AFX type, BEA type, CHA type, DDR type, ERI type, ETL type, FAU type (X type, Y type), GIS type, LEV type, LTA type, MEL type, MFI type, MOR type, PAU type, RHO type, SAT type, SOD type.

[0096] Among these zeolites, there can be mentioned a zeolite of LTA type.

[0097] The maximum number of members of the ring of the zeolite is, for example, 12 or less, preferably 10 or less, more preferably 8 or less, and is, for example, 6 or more.

[0098] The zeolite membrane contains SiO2and Al2O3. The zeolite membrane can further contain an alkali metal. The alkali metal is, for example, sodium (Na) or potassium (K).

[0099] The molar ratio of SiO2 / Al2O3in the zeolite membrane is, for example, 100 or less, preferably 10 or less, more preferably less than 5, and further preferably 4 or less. If the molar ratio of SiO2 / Al2O3in the zeolite membrane is the above upper limit or less, the breakage of the zeolite membrane can be more further stably suppressed. The lower limit of the molar ratio of SiO2 / Al2O3in the zeolite membrane is typically 2. The molar ratio of SiO2 / Al2O3may be measured using, for example, a scanning electron microscope-energy dispersive X-ray spectrometry (SEM-EDX; acceleration voltage of X-rays 10 kV).

[0100] The average pore diameter of the separation membrane 2 can be arbitrarily and appropriately selected depending on the adsorbing substance. The average pore diameter of the separation membrane 2 is, for example, 0.2 nm to 1 nm, and preferably 0.3 nm to 0.5 nm. If the average pore diameter of the separation membrane 2 is made smaller, the selectivity increases. The average pore diameter of the separation membrane 2 is smaller than the average pore diameter of the base material 3. In the case where the separation membrane 2 is a zeolite membrane, the maximum number of rings of the zeolite is set to n, and the arithmetic average of the short diameter and the long diameter of the n-ring pore is set to the average pore diameter. The n-ring pore refers to a pore in which the number of oxygen atoms that form a ring structure by bonding with T atoms is n. In the case where a plurality of n-ring pores having the same n exist, the arithmetic average of the short diameter and the long diameter of all the n-ring pores is set to the average pore diameter of the zeolite. The average pore diameter of the zeolite membrane is determined by the framework structure of the zeolite, and can be solved from the value disclosed in "Database of Zeolite Structures" [online] of the International Zeolite Association, Internet <URL: http: / / www.iza-structure.org / databases / >.

[0101] 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. If the separation membrane is made thicker, the selectivity increases. If the separation membrane is made thinner, the permeation rate increases.

[0102] 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 further preferably 0.5 μm or less. The surface roughness (Ra) can be measured in accordance with, for example, JIS B 0601.

[0103] The separation membrane 2 can be formed by an arbitrary and appropriate method depending on the material constituting the membrane. For example, the zeolite membrane is obtained by coating a zeolite as a seed on a separation membrane, and immersing the base material to which the seed is attached in a raw material solution, and performing hydrothermal synthesis using the seed as a nucleus to grow the zeolite, thereby obtaining a zeolite membrane. The raw material solution contains, for example, a silicon source, an aluminum 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, a raw material slurry obtained by mixing an organic binder, a ceramic raw material, and a solvent can be used to form the separation membrane.

[0104] It should be noted that Figures 1 to 5 One separation membrane composite 10 is exemplified, but a plurality of separation membrane composites 10 can be arranged in series in the length direction to constitute the first flow path 21 and the second flow path 22.

[0105] B-2. Supply portion, first recovery portion, and second recovery portion

[0106] 1. In one embodiment, as shown in Figure 6 the separation device 1 has, in addition to the separation membrane complex 10, a supply section 4 that supplies the mixture to the first flow path 21 of the separation membrane complex 10, a first recovery section 5 that recovers the fluid that has passed through the first flow path 21, and a second recovery section 6 that recovers the permeated substance that has permeated through the separation membrane 2. The separation device 1 of the illustrated example is configured so that the temperature, pressure, and flow rate of the mixture that passes through the first flow path can be adjusted. Note that Figure 6 The one embodiment of the present application has been described, but the present application is not limited thereto.

[0107] The supply section 4 of the illustrated example is capable of adjusting the temperature and flow rate of the mixture supplied (flowed in) to the first flow path 21. The supply section 4 has a supply line 41, a heating device 42, and a flow rate adjustment mechanism 43.

[0108] The supply line 41 is a pipe for supplying the mixture to the first flow path 21. Although not shown, the upstream end portion in the supply direction of the mixture in the supply line 41 is connected to a storage tank that stores, for example, the mixture. The downstream end portion in the supply direction of the mixture in the supply line 41 is connected to the inflow port of the first flow path 21 that the separation membrane complex 10 has (see Figure 1 ).

[0109] The heating device 42 is provided to the supply line 41 and is capable of heating the mixture that passes through the supply line 41. The heating device 42 can adopt any appropriate configuration.

[0110] The flow rate adjustment mechanism 43 can adjust the flow rate of the mixture that passes through the supply line 41. The flow rate adjustment mechanism 43 can adopt any appropriate configuration. In the illustrated example, the flow rate adjustment mechanism 43 is provided to the supply line 41 between the heating device 42 and the separation membrane complex 10.

[0111] Note that the supply section 4 can include other devices as needed. For example, in the supply line 41, other devices can be present between the flow rate adjustment mechanism 43 and the separation membrane complex 10.

[0112] The first recovery section 5 of the illustrated example can adjust the pressure of the mixture in the first flow path 21. The first recovery section 5 has a first recovery line 51 and a pressure adjustment valve 52.

[0113] The first recovery line 51 is a pipe through which the fluid (mixture in which the adsorbed substance has been reduced) that has passed through the first flow path 21 that the separation membrane complex 10 has passes. The upstream end portion in the passage direction of the fluid in the first recovery line 51 is connected to the outflow port of the first flow path 21 that the separation membrane complex 10 has (see Figure 1The upstream end of the fluid in the first recovery line 51 in the direction of flow is connected to the outlet of the second flow path 22 provided in the separation membrane complex 10, although not shown. The downstream end of the fluid in the first recovery line 51 in the direction of flow is connected to, for example, a storage tank, although not shown.

[0114] The pressure adjustment valve 52 is provided in the first recovery line 51. The pressure adjustment valve 52 is capable of adjusting the opening degree of the first recovery line 51, and thereby capable of adjusting the pressure of the mixture in the first flow path 21.

[0115] The second recovery section 6 of the illustrated example is provided with a second recovery line 61.

[0116] The second recovery line 61 is a pipe through which the fluid (at least containing the permeated substance) that has passed through the second flow path 22 of the separation membrane complex 10 is supplied. The upstream end of the fluid in the second recovery line 61 in the direction of flow is connected to the outlet of the second flow path 22 provided in the separation membrane complex 10. The downstream end of the fluid in the second recovery line 61 in the direction of flow is connected to, for example, a storage tank, although not shown.

[0117] In the above-described embodiment, the supply section 4 on the upstream side with respect to the separation membrane complex 10 adjusts the temperature and the flow rate of the mixture supplied (flowed into) to the first flow path 21, and the first recovery section 5 on the downstream side with respect to the separation membrane complex 10 adjusts the pressure of the mixture in the first flow path 21, but the configuration of the separation apparatus 1 is not limited thereto. The supply section 4 can be configured to be capable of adjusting the pressure of the mixture in the first flow path 21. In addition, the first recovery section 5 can be configured to be capable of adjusting the flow rate of the mixture that has passed through the first flow path 21.

[0118] C. Details of the operation method of the separation apparatus

[0119] Next, the details of the operation method of the separation apparatus 1 will be described.

[0120] The operation method of the above-described separation apparatus 1 can be well applied to both the transient operation of the separation apparatus and the stable operation of the separation apparatus.

[0121] C-1. Transient operation

[0122] The transient operation of the separation apparatus is performed by supplying the mixture to the first flow path and changing the temperature and / or the pressure of the mixture.

[0123] In the transient operation of the separation apparatus, typically, the difference between the maximum value and the minimum value of the temperature of the mixture in the last 1 hour exceeds 10°C, and / or the maximum value and the minimum value of the pressure of the mixture in the last 1 hour satisfy the following formula (7).

[0124] [(maximum value of the pressure of the mixture in the last 1 hour / minimum value of the pressure of the mixture in the last 1 hour) - 1] x 100 > 10 (7)

[0125] As the transition operation of the separation device, for example, there can be mentioned: a first transition operation in which the temperature and / or pressure of the mixture is increased; and a second transition operation in which the temperature and / or pressure of the mixture is decreased.

[0126] C-1-1. First transition operation

[0127] In one embodiment, in the first transition operation of the separation device, the mixture is supplied to the first flow path 21 in such a manner that the adsorbent concentration distribution of the mixture circulating in the first flow path 21 is below the above upper limit, and the temperature of the supplied mixture is increased, and / or the pressure in the first flow path 21 is increased. More preferably, the temperature of the supplied mixture is increased and the pressure in the first flow path 21 is increased. Further preferably, the following procedures are sequentially repeated: a procedure in which the temperature of the mixture is increased while the pressure in the first flow path 21 is maintained substantially constant; and a procedure in which the pressure in the first flow path 21 is increased while the temperature of the mixture is maintained substantially constant.

[0128] In the illustrated example, the supply portion 4 supplies the mixture to the first flow path 21 at a desired temperature and flow rate. In addition, the pressure adjusting valve 52 adjusts the opening degree of the first recovery line 51 in such a manner that the mixture in the first flow path 21 reaches a desired pressure.

[0129] The flow rate of the mixture passing through the supply line 41 is arbitrarily and appropriately adjusted in such a manner that the adsorbent concentration distribution of the mixture circulating in the first flow path 21 is below the above upper limit. In the first transition operation of the separation device, the flow rate of the mixture passing through the supply line 41 is preferably large.

[0130] For example, with respect to a generally cylindrical flow path having a diameter φ of 2.4 mm, the flow rate per 1 hole is 0.1 Nm 3 / h or more, typically 7.2 Nm 3 / h or less.

[0131] For example, with respect to a pipe type or a generally cylindrical flow path having a diameter φ of 10 mm, the flow rate per 1 hole is 0.5 Nm 3 / h or more, typically 124 Nm 3 / h or less.

[0132] The above flow rate is one example in the case where the above average Reynolds number is 2000 or more, and if the adsorbent concentration distribution in the passing direction of the mixture passing through the first flow path exceeds 0 and is 0.3 or less, the flow rate is not particularly limited.

[0133] As the first transient operation of the separation device, representative examples include the start of operation of the separation device.

[0134] The start of operation of the separation device refers to a process from a state in which the flow rate of the mixture supplied to the first flow path is zero to a period of the stable operation described later, and is a process in which the flow rate of the mixture is greater than zero. The flow rate of zero refers to a case in which the flow rate is lower than the low cut from the viewpoint of the display accuracy of the meter.

[0135] By applying the above-described operation method of the separation device at the start of operation of the separation device, it is possible to suppress the breakage of the separation membrane 2, and to raise the separation membrane 2 from the initial temperature to the prescribed adsorption temperature.

[0136] At the start of operation of the separation device, the initial temperature of the separation membrane is, for example, 5°C to 25°C, and the initial pressure in the first flow path is, for example, 0.1 MPaG to 1 MPaG.

[0137] At the end of the start of operation of the separation device, the temperature (adsorption temperature) of the separation membrane is, for example, 100°C to 350°C, and the pressure in the first flow path is, for example, 0.1 MPaG to 20 MPaG.

[0138] Note that the first transient operation of the separation device is not limited to the start of operation of the separation device. For example, the first transient operation of the separation device can be performed during a period from a stable operation in which the temperature and / or the pressure of the mixture is relatively low to a stable operation in which the temperature and / or the pressure of the mixture is relatively high.

[0139] C-1-2. Second Transient Operation

[0140] In one embodiment, in the second transient operation of the separation device, the mixture is supplied to the first flow path 21 in such a manner that the adsorbent concentration distribution of the mixture flowing through the first flow path 21 is below the upper limit described above, while the pressure in the first flow path 21 is decreased, and then the temperature of the supplied mixture is decreased.

[0141] In the second transient operation of the separation device, the supply unit 4 and the first recovery unit 5 also act in the same manner as described above, and appropriately adjust the temperature, the pressure, and the flow rate of the mixture passing through the first flow path. The description of the flow rate in the second transient operation of the separation device is the same as that in the first transient operation described above.

[0142] As the second transient operation of the separation device, representative examples include the stop of operation of the separation device.

[0143] The stop of operation of the separation device refers to a process from the stable operation described later to a state in which the flow rate of the mixture supplied to the first flow path is zero.

[0144] In the stage where the pressure in the first flow path and / or the temperature of the mixture is below the desired threshold value in the operation stop of the separation apparatus, the supply of the mixture to the first flow path is stopped, and the flow rate of the mixture becomes zero. Thus, the operation stop of the separation apparatus ends.

[0145] By applying the above-described operation method of the separation apparatus, the breakage of the separation membrane 2 can be suppressed, and the separation membrane 2 can be suppressed to room temperature (23°C) at the time of the operation stop of the separation apparatus.

[0146] Note that the second transitional operation of the separation apparatus is not limited to the operation stop of the separation apparatus. For example, the second transitional operation of the separation apparatus can be performed during the period from the stable operation with relatively high temperature and / or pressure of the mixture to the stable operation with relatively low temperature and / or pressure of the mixture.

[0147] Further, the first transitional operation and the second transitional operation can be continuously performed.

[0148] C-2. Stable operation

[0149] The stable operation of the separation apparatus refers to the period where the flow rate of the supplied mixture is greater than zero and the temperature and the pressure of the supplied mixture are substantially constant. Note that substantially constant means a state where the inlet temperature and the inlet pressure of the first flow path 21 are not intentionally varied, and in particular, the variation range is not limited, and for example, if the difference between the maximum value and the minimum value of the temperature in the last 1 hour is 10°C or less and the difference between the maximum value and the minimum value of the pressure in the last 1 hour satisfies the following formula (8), it can be considered that the temperature and the pressure are substantially constant. If the variation range is like this, the separation performance of the separation membrane can be stabilized.

[0150] [(maximum value of the pressure of the mixture in the last 1 hour / minimum value of the pressure of the mixture in the last 1 hour) - 1] x 100 ≤ 10 ··· (8)

[0151] In one embodiment, in the stable operation of the separation apparatus, the mixture is supplied to the first flow path 21 in such a manner that the adsorbent concentration distribution of the mixture flowing through the first flow path 21 is below the above-described upper limit, and the temperature of the supplied mixture is substantially maintained at the adsorption temperature, and the pressure in the first flow path 21 is substantially maintained constant. In the stable operation of the separation apparatus, typically, the mixture in a gaseous state is supplied to the first flow path 21.

[0152] In the illustrated example, the supply part 4 and the first recovery part 5 operate in the same manner as described above, and the temperature, the pressure, and the flow rate of the mixture passing through the first flow path are appropriately adjusted. The description of the flow rate in the stable operation of the separation apparatus is the same as that in the operation start described above.

[0153] Thus, breakage of the separation membrane 2 can be suppressed, and the separation membrane 2 can smoothly separate and remove the adsorbent from the mixture passing through the first flow path 21.

[0154] Industrial applicability

[0155] The method for operating the separation device according to the embodiments of the present application is used for separation of a specific substance in a mixture, and can be preferably used for separation of water from an aqueous mixture.

[0156] Explanation of symbols

[0157] 1 separation device

[0158] 2 separation membrane

[0159] 3 base material

[0160] 21 first flow path

[0161] 22 second flow path

Claims

1. A method for operating a separation apparatus having a separation membrane, the method for operating the separation apparatus is characterized by the separation apparatus has: a first flow path to which a mixture containing an adsorbent substance adsorbed to the separation membrane is supplied; and a second flow path through which a substance that has permeated the separation membrane flows, the method for operating the separation apparatus includes a step of supplying the mixture to the first flow path in such a manner that the concentration distribution of the adsorbent substance in the passing direction of the mixture exceeds 0 and is 0.3 or less.

2. The method for operating the separation apparatus according to claim 1, wherein the adsorbent substance is water.

3. The method for operating the separation apparatus according to claim 2, wherein the mixture contains water and an organic compound.

4. The method for operating the separation apparatus according to any one of claims 1 to 3, wherein in the step of supplying the mixture to the first flow path, the average Reynolds number of the mixture flowing in the first flow path is adjusted to 2000 or more.

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

6. The method for operating the separation apparatus according to claim 5, wherein the molar ratio of Si02 / Al203 in the zeolite membrane is less than 5.

7. The method for operating the separation apparatus according to any one of claims 1 to 3, wherein in the step of supplying the mixture to the first flow path, the temperature of the supplied mixture is increased, and / or the pressure in the first flow path is increased.

8. The method for operating the separation apparatus according to any one of claims 1 to 3, wherein in the step of supplying the mixture to the first flow path, the temperature of the supplied mixture is decreased after the pressure in the first flow path is decreased.

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

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