External pressure type hollow fiber membrane module and manufacturing method thereof

Abstract

An external pressure type hollow fiber membrane assembly, comprising: a hollow fiber membrane bundle, a shell, a first straightening cylinder between the open end of the hollow fiber membrane bundle and the shell end, a second straightening cylinder between the closed end of the hollow fiber membrane bundle and the shell end, a first bonding fixing portion at the open end of the hollow fiber membrane, a second bonding fixing portion at the closed end of the hollow fiber membrane bundle, a protective component and a cover, the second bonding fixing portion having at least one through hole parallel to the length direction of the shell on the periphery of the hollow fiber membrane bundle, the through hole being configured to be adjacent to the outer peripheral surface of the hollow fiber membrane bundle, and having a partial arc shape with a width in a cross-sectional shape in a direction orthogonal to the length direction of the shell, and the protective component being configured to be in contact with the hollow fiber membrane bundle and the through hole between the hollow fiber membrane bundle and the through hole.

Description

Technical Field

[0001] The invention relates to an external pressure type hollow fiber membrane component and a manufacturing method thereof. Background Art

[0002] In the production line of ultrapure water used in the manufacture of electronic / electrical components such as semiconductors and display elements, before the ultrapure water produced using microfiltration membranes, ion exchange resins, and reverse osmosis filtration membranes is supplied to the point of use, a microfiltration membrane or an ultrafiltration membrane is used for final filtration. In this final filtration, an external pressure type hollow fiber membrane module is mainly used, which accommodates a hollow fiber membrane bundle formed by bundling a plurality of hollow fiber membranes in a housing, supplies the treated water to the outside of the hollow fiber membrane, and performs filtration on the inside (hollow part) of the hollow fiber membrane.

[0003] For example, the external pressure type hollow fiber membrane assembly described in Patent Document 1 is erected in a manner that its length direction is the vertical direction, and the upper nozzle for filtering water discharge and the lower nozzle for treating water supply are respectively arranged on the upper side and the lower side in the vertical direction in a manner that protrudes in a direction orthogonal to the length direction of the shell. Both ends of the hollow part of the hollow fiber membrane are open, and the ends of the hollow fiber membrane bundle are bonded and fixed to the shell by an adhesive fixing layer. The treated water supplied from the lower nozzle is filtered from the outside to the inside (hollow part) of the hollow fiber membrane in the shell, and the filtered water is discharged from the upper and lower ends of the shell, and the discharged water is discharged from the upper nozzle.

[0004] In addition, the external pressure type hollow fiber membrane assembly described in Patent Document 2 is erected in a manner that its length direction is the vertical direction, and the nozzle for discharging the discharged water is arranged on the upper side in the vertical direction in a manner that protrudes in a direction orthogonal to the length direction of the shell. One end of the hollow portion of the hollow fiber membrane is sealed, and the other end of the hollow portion is open, and is arranged in the shell in a manner that the sealed end becomes the lower side in the vertical direction and the open end becomes the upper side in the vertical direction. In addition, only the open end side of the hollow fiber membrane bundle is adhesively fixed to the shell. The treated water supplied from the lower end of the shell is supplied to the outside of the hollow fiber membrane through the gap between the inner wall of the shell and the sealing portion that seals one end of the hollow fiber membrane and is filtered toward the inner side (hollow portion) of the hollow fiber membrane, and the filtered water is discharged from the upper end of the shell, and the discharged water is discharged from the nozzle.

[0005] In the external pressure type hollow fiber membrane module described in Patent Document 3, similar to Patent Document 2, when the treated water is supplied from the lower end of the shell, the water is filtered from the outer side to the inner side (hollow part) of the hollow fiber membrane, the filtered water is discharged from the upper end of the shell, and the discharged water is discharged from the nozzle, but the two ends (sealed end and open end) of the hollow fiber membrane bundle are bonded to the shell by the bonding fixing part. In addition, the treated water supplied from the lower end of the shell is supplied to the outer side of the hollow fiber membrane through the through hole provided on the bonding fixing part.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Publication No. 2012-45453

[0009] Patent Document 2: Japanese Patent Application Publication No. 2015-182056

[0010] Patent Document 3: Japanese Patent Application Publication No. 2017-100105 Summary of the invention

[0011] Problem that the invention aims to solve

[0012] In the external pressure type hollow fiber membrane assembly described in Patent Document 1, since treated water is supplied to the hollow fiber membrane from the lower nozzle in the vertical direction and discharged water is discharged from the upper nozzle in the vertical direction, there is the following problem: vertical water pressure is applied to the hollow fiber membrane, and stress is concentrated on the fixed parts at both ends of the hollow fiber membrane bundle, which is prone to damage at the end (root) of the hollow fiber membrane.

[0013] In the external pressure type hollow fiber membrane assembly described in Patent Document 2, since the treated water is supplied to the hollow fiber membrane in parallel, the above-mentioned stress concentration caused by the supply of the treated water is alleviated. However, since the stress concentration caused by the discharge of the discharged water still exists, there is a problem that the maximum deflection near the discharge nozzle of the discharged water increases, and the end (root) of the hollow fiber membrane is still prone to damage. In addition, since the sealed end side of the hollow fiber membrane is not bonded and fixed to the shell, the hollow fiber membrane bundle is sometimes pushed up by the inflow of the treated water, resulting in buckling of the hollow fiber membrane.

[0014] In the external pressure type hollow fiber membrane module described in Patent Document 3, since the treated water is supplied to the hollow fiber membranes in parallel, and the two ends of the hollow fiber membrane bundle are bonded and fixed to the shell, the concentration of stress caused by the supply of the treated water as described above is alleviated, and the maximum deflection amount is also reduced. However, in order to increase the number of hollow fiber membranes per unit volume and the amount of treated water supplied to the hollow fiber membrane bundle, reduce pressure loss, and filter efficiently, there is room for improvement in the shape and opening area of ​​the through hole.

[0015] Furthermore, the external pressure type hollow fiber membrane module described in Patent Document 3 is suitable for use in a filtration device for removing endotoxin from raw water clarified by a pure water production device, and therefore further improvements are required in the hollow fiber membranes used in order to use them for final filtration of ultrapure water.

[0016] An object of the present invention is to provide an external pressure type hollow fiber membrane module having high durability and excellent uniformity of pressure distribution and velocity distribution of a fluid flowing therethrough.

[0017] Methods for solving problems

[0018] The present inventors have conducted intensive studies to solve the above problems and have found that the above problems can be solved by setting the opening shape of the through holes for supplying the water to be treated to the hollow fiber membrane bundle to a predetermined shape, thereby completing the present invention.

[0019] That is, the present invention is as follows.

[0020] [1] An external pressure type hollow fiber membrane module, characterized by comprising:

[0021] A hollow fiber membrane bundle is formed by bundling a plurality of hollow fiber membranes with one end closed and the other end open;

[0022] A shell, which is a cylindrical body having at least one nozzle on a side surface, and houses the hollow fiber membrane bundle in such a manner that the closed end of the hollow fiber membrane and the open end of the hollow fiber membrane are respectively oriented toward both end sides in the length direction of the cylindrical body;

[0023] A first fairing cylinder installed between the open end of the hollow fiber membrane bundle and the end of the shell;

[0024] A second fairing cylinder installed between the closed end of the hollow fiber membrane bundle and the end of the shell;

[0025] a first bonding and fixing portion that bonds and fixes the hollow fiber membranes to each other and the hollow fiber membrane bundle to the inner wall of the housing at the end side of the opening of the hollow fiber membrane;

[0026] A second bonding and fixing portion, which bonds and fixes the hollow fiber membranes to each other and the hollow fiber membrane bundle to the inner wall of the shell on the closed end side of the hollow fiber membrane, and has at least one through hole parallel to the length direction of the shell on the outer periphery of the hollow fiber membrane bundle;

[0027] a protective member covering the entire periphery of the outer peripheral surface of the hollow fiber membrane bundle in a state of being in close contact with the outer peripheral surface of the hollow fiber membrane bundle in at least one of an end region of at least a predetermined length from the first adhesive fixing portion toward the second adhesive fixing portion and an end region of at least a predetermined length from the second adhesive fixing portion toward the first adhesive fixing portion; and

[0028] A cover having an opening and mounted at both ends of the housing in the longitudinal direction,

[0029] The through hole is arranged adjacent to the outer peripheral surface of the hollow fiber membrane bundle, and the cross-sectional shape of the through hole in a direction perpendicular to the longitudinal direction of the shell is a partial arc shape having a width.

[0030] The protection member is provided between the hollow fiber membrane bundle and the through-hole so as to be in contact with the hollow fiber membrane bundle and the through-hole.

[0031] [2] The external pressure type hollow fiber membrane module according to [1], wherein:

[0032] In a cross section in a direction perpendicular to the length direction of the shell,

[0033] A ratio (A / S) of a total opening area A of the through holes to an area S obtained by subtracting an area defined by the outer peripheral surface of the protection member from an area defined by the inner wall of the housing is 0.2 to 0.7.

[0034] [3] An external pressure type hollow fiber membrane assembly according to [1] or [2], wherein the sum of the opening areas of the through holes is set to A, the sum of the opening areas of the hollow portions of the hollow fiber membranes is set to B, and the opening area of ​​the opening portion of the cover is set to C, and the relationship among A, B, and C is 0.5<A / B<1.5, and 0.5<C / B<1.5.

[0035] [4] The external pressure type hollow fiber membrane module according to any one of [1] to [3], wherein the protective member is disposed over the entire range from the first adhesive fixing portion to the second adhesive fixing portion.

[0036] [5] The external pressure type hollow fiber membrane module according to any one of [1] to [4], wherein the protective member is a member obtained by forming a mesh-like member into a cylindrical shape.

[0037] [6] The external pressure type hollow fiber membrane module according to [5], wherein the wire diameter of the mesh member is 0.2 to 1.5 mm, and the opening ratio is 40 to 90%.

[0038] [7] The external pressure type hollow fiber membrane module according to any one of [1] to [6], wherein the opening of at least one of the covers has a structure sealed and fixed by a gasket having an inner diameter that is the same as the inner diameter of the opening.

[0039] [8] A method for manufacturing an external pressure type hollow fiber membrane module according to any one of [1] to [7], characterized in that:

[0040] The first straightening cylinder and the second straightening cylinder are installed on the shell, and after the hollow fiber membrane bundle covered by the protective component is inserted into the shell, a casting fixture is installed on the approximately disc-shaped surface in such a way that the convex portion is located between the protective component and the shell, and the casting fixture has at least one convex portion with a cross-section parallel to the approximately disc-shaped surface and a partial arc shape with a width. After the gap between the protective component and the shell is filled and cured with a potting material, the casting fixture is removed, so that the outer peripheral surface of the hollow fiber membrane bundle is in a state of close contact with the protective component, and at least one through hole is opened on the outside of the protective component, and the cross-sectional shape of the through hole in a direction perpendicular to the length direction of the shell is a partial arc shape with a width.

[0041] Effects of the Invention

[0042] According to the present invention, it is possible to provide an external pressure type hollow fiber membrane module which has high durability and excellent uniformity of pressure distribution and velocity distribution of a fluid flowing therein. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a longitudinal cross-sectional view showing a schematic structure of one embodiment of the external pressure type hollow fiber membrane module according to the present invention.

[0044] Figure 2 It is cut along the line AA Figure 1 A cross-sectional view of an external pressure type hollow fiber membrane module is shown.

[0045] Figure 3 (a) means manufacturing Figure 1 A perspective view of an example of a casting jig for making through holes in an external pressure type hollow fiber membrane module. (b) is a perspective view showing the manufacturing process of the casting jig. Figure 1 The external pressure type hollow fiber membrane module shown is a perspective view of a cup for centrifugal casting mounted on the end of the first cylindrical member to form the first adhesive fixing portion.

[0046] Figure 4 Schematic diagrams showing evaluation devices used in filtration evaluation of Examples and Comparative Examples. (a) shows the evaluation devices used in Examples 1 and 2 and Comparative Example 2-1, and (b) shows the evaluation device used in Comparative Example 1.

[0047] Figure 5 These are schematic diagrams showing a simulation model used in Example 3. (a) shows the whole, and (b) shows the structure near the inlet.

[0048] Figure 6 These are diagrams showing the simulation results of the flow analysis of Example 3. (a) shows the pressure distribution of water, and (b) shows the velocity distribution of water.

[0049] Figure 7 These are diagrams showing the simulation results of the flow analysis of Example 4. (a) shows the pressure distribution of water, and (b) shows the velocity distribution of water.

[0050] Figure 8 These are schematic diagrams showing the simulation model used in Comparative Example 2-2: (a) shows the whole, and (b) shows the structure near the inlet.

[0051] Fig. 9 The figures show the water velocity distribution as the simulation result of the flow analysis of Comparative Example 2-2. (a) is the distribution diagram observed from the longitudinal direction of the simulation model, and (b) is the distribution diagram observed from the direction orthogonal to the longitudinal direction of the simulation model.

[0052] Fig.10 These are schematic diagrams showing a simulation model used in Comparative Example 3. (a) shows the entirety, and (b) shows the structure near the inlet.

[0053] Fig.11 These are diagrams showing the simulation results of the flow analysis of Comparative Example 3. (a) shows the pressure distribution of water, and (b) shows the velocity distribution of water.

[0054] Fig.12 These are schematic diagrams showing a simulation model used in Comparative Example 4. (a) shows the entirety, and (b) shows the structure near the inlet.

[0055] Fig.13 These are diagrams showing the simulation results of the flow analysis of Comparative Example 4. (a) shows the pressure distribution of water, and (b) shows the velocity distribution of water. DETAILED DESCRIPTION

[0056] Hereinafter, a mode for carrying out the present invention (hereinafter referred to as “the present embodiment”) will be described in detail, but the present invention is not limited to the following description and can be carried out with various modifications within the scope of the gist thereof.

[0057] [External pressure hollow fiber membrane module]

[0058] The external pressure type hollow fiber membrane module of the present embodiment is particularly suitable as a final filtration membrane module for ultrapure water used for cleaning in the production of silicon wafers, LSIs, liquid crystals, and the like.

[0059] The configuration of an example of an external pressure type hollow fiber membrane module (hereinafter, also simply referred to as a “hollow fiber membrane module”) according to the present embodiment will be described with reference to the drawings.

[0060] Figure 1 : is a longitudinal cross-sectional view showing a schematic structure of an example of an external pressure type hollow fiber membrane module of the present embodiment. Figure 1 The arrows are used to indicate the up and down directions. Figure 1 The vertical direction shown will be described as the vertical direction of the hollow fiber membrane module 1 .

[0061] like Figure 1 As shown, the hollow fiber membrane module 1 of the present embodiment includes a hollow fiber membrane bundle 3 in which a plurality of hollow fiber membranes 2 are bundled, a cylindrical casing 4 that accommodates the hollow fiber membrane bundle 3, and lids 8a and 8b.

[0062] As the hollow fiber membrane 2, a reverse osmosis membrane, a nanofiltration membrane, an ultrafiltration membrane, and a microfiltration membrane can be used. The material of the hollow fiber membrane is not particularly limited, and examples thereof include polysulfone, polyethersulfone, polyacrylonitrile, polyimide, polyetherimide, polyamide, polyetherketone, polyetheretherketone, polyethylene, polypropylene, poly(4-methylpentene), ethylene-vinyl alcohol copolymer, cellulose, cellulose acetate, polyvinylidene fluoride, ethylene-tetrafluoroethylene copolymer, and polytetrafluoroethylene, and composite materials thereof can also be used.

[0063] The shape of the hollow fiber membrane is preferably 100 to 3000 μm in inner diameter and 200 to 4000 μm in outer diameter, more preferably 200 to 2000 μm in inner diameter and 300 to 3000 μm in outer diameter, and still more preferably 400 to 1000 μm in inner diameter and 500 to 2000 μm in outer diameter. If the inner diameter and outer diameter are within the above range, both permeation flux and durability are achieved, and the membrane can be applied to the final filtration of ultrapure water.

[0064] The molecular weight cutoff of the hollow fiber membrane is preferably 6000 or more, more preferably more than 6000. If the molecular weight cutoff of the hollow fiber membrane is within the above range, it can be suitably used as the final filtration membrane assembly of ultrapure water used in the cleaning of silicon wafers, LSIs, liquid crystals, etc. In general, as ultrapure water, it is preferred that the number of mixed particles is small, and even if it is mixed, ultrapure water is only suppressed to smaller particles, but as ultrapure water used in the cleaning of silicon wafers, LSIs, liquid crystals, etc., the surface impurities of the silicon wafers, etc. are rinsed for use. Therefore, from the viewpoint of ensuring a large amount of water, it is preferred to use a highly permeable hollow fiber membrane with a molecular weight cutoff within the above range. In addition, in the filtration for the purpose of removing endotoxins, since the purpose is to obtain water equivalent to distilled water used in the cleaning of injection solutions (dilution water), containers of pharmaceuticals, etc., as filtered water, most of the hollow fiber membranes with a molecular weight cutoff less than the above range are used, such as the amount of endotoxin is set to below the detection limit (negative), water quality is prioritized over permeation, and the molecular weight cutoff is less than the above range. On the other hand, in the filtration of ultrapure water used for cleaning in the manufacture of silicon wafers, LSIs, liquid crystals, etc., the size of the removal object is relatively large compared to endotoxins. In addition, as mentioned above, from the perspective of ensuring a large amount of water, it is preferred to use a highly permeable hollow fiber membrane with a molecular weight cutoff in the above-mentioned range.

[0065] The number of hollow fiber membranes also depends on the size of the hollow fiber membranes and the inner cross-sectional area of ​​the shell housing the hollow fiber membranes, but from the perspective of collecting more filtered water, it is preferably 5,000 to 20,000, more preferably 7,000 to 15,000, and even more preferably 9,000 to 13,000.

[0066] The housing 4 is provided with pipe connection covers 8a and 8b with funnel-shaped cross sections at both end openings. The covers 8a and 8b are formed with openings (pipelines) connected to the pipes. The covers 8a and 8b are fixed to the housing 4 by nuts 13.

[0067] An annular groove is formed on the end surface of the cover 8a, 8b on the housing 4 side and the end surface of the housing 4 on the cover 8a, 8b side, and the groove sandwiches an O-ring 14. The two ends of the housing 4 and the cover 8a, 8b are sealed liquid-tightly by the O-ring 14. Specifically, the sealing structure performed by the O-ring 14 can be set to the structure described in Japanese Patent Application Laid-Open No. 2017-39122.

[0068] In addition, it is preferable that the openings of the covers 8a and 8b and the pipes connected thereto are sealed and fixed by a gasket having the same inner diameter as the inner diameter of the openings of the covers 8a and 8b. If the inner diameter of the openings of the covers 8a and 8b is the same as the inner diameter of the gasket, it is possible to suppress the stagnation of liquid related to the corresponding part of the fluid flowing inside and the dust caused by the turbulence of the fluid.

[0069] The housing 4 is composed of a first tubular component 9a integrally formed with a nozzle 12a, a second tubular component 9b integrally formed with a nozzle 12b, and a third tubular component 10 in a straight tube shape disposed between the first tubular component 9a and the second tubular component 9b, which are joined together. The nozzle 12a and the nozzle 12b are respectively arranged at the side of the end of the housing 4, and are arranged to protrude in a direction orthogonal to the length direction of the housing 4. The nozzle 12a is a nozzle for discharging discharge water during the external pressure filtration process. Since the nozzle 12b is not particularly used in the hollow fiber membrane module 1 of the present embodiment, its opening is sealed.

[0070] The hollow fiber membrane module 1 of the present embodiment is erected so that its longitudinal direction is in the vertical direction, and is arranged so that the nozzle 12a is arranged on the upper side in the vertical direction and the nozzle 12b is arranged on the lower side in the vertical direction.

[0071] like Figure 1 As shown, a first straightening tube 11 a and a second straightening tube 11 b are respectively installed between both ends of the hollow fiber membrane bundle 3 and the first tubular member 9 a and the second tubular member 9 b .

[0072] The first straightening cylinder 11a and the second straightening cylinder 11b are formed in a cylindrical shape. The first straightening cylinder 11a is arranged between the opening on the inner side of the shell 4 of the upper nozzle 12a and the hollow fiber membrane bundle 3, and the second straightening cylinder 11b is arranged between the opening on the inner side of the shell 4 of the lower nozzle 12b and the hollow fiber membrane bundle 3, and they are respectively arranged to surround the outer periphery of the hollow fiber membrane bundle 3.

[0073] The first flow straightening tube 11 a and the second flow straightening tube 11 b are provided to maintain a gap between the hollow fiber membrane bundle 3 and the inner wall of the housing 4 near the nozzles 12 a and 12 b .

[0074] The upper end of the first rectification cylinder 11 a may be bonded and fixed in a first bonding and fixing portion 5 a described below, and the lower end of the second rectification cylinder 11 b may be bonded and fixed in a second bonding and fixing portion 5 b described below.

[0075] By installing the first straightening cylinder 11a and the second straightening cylinder 11b at the two ends of the shell 4, in the manufacture of the hollow fiber membrane assembly 1, when the hollow fiber membrane bundle 3 wrapped by the protective component 7 is bonded and fixed in the shell 4 by the centrifugal bonding described later, the hollow fiber membrane bundle 3 can be prevented from falling downward during centrifugation.

[0076] A first bonding portion 5a and a second bonding portion 5b are formed at both ends of the hollow fiber membrane bundle 3 to bond and fix the hollow fiber membranes 2 to each other and the hollow fiber membrane bundle 3 to the inner wall of the housing 4 using a potting material.

[0077] In this way, by gluing and fixing both ends of the hollow fiber membrane bundle 3, the maximum deflection of the hollow fiber membrane bundle 3 becomes smaller and stress concentration is alleviated compared to the case where only one end is gluing and fixing. Therefore, the breakage of the hollow fiber membrane 2 can be prevented, resulting in a hollow fiber membrane component with good durability.

[0078] As the potting material, preferably, there are polymer materials such as epoxy resin, vinyl ester resin, polyurethane resin, unsaturated polyester resin, olefin polymer, silicone resin and fluorine-containing resin, etc. These polymer materials may be used alone or in combination of two or more.

[0079] In addition, the first adhesive fixing part 5a and the second adhesive fixing part 5b composed of these potting materials need to have pressure resistance that can withstand the pressure difference between the primary side and the secondary side caused by pressurization during filtration, so they preferably have moderate hardness. On the other hand, in order to reliably prevent the breakage of the hollow fiber membrane 2 caused by the flow of fluid during physical cleaning for a longer period of time, it is preferred to use a potting material with moderate softness. Therefore, in order to impart sufficient pressure resistance required for use and reliably prevent membrane breakage, it is preferred to use a potting material with a hardness of 80D to 50A within the use temperature range.

[0080] The hardness mentioned here refers to the value displayed after 10 seconds when a Durometer type D or A is pressed on a material surface having a substantially smooth surface in accordance with JIS K6253. If the value exceeds 80D, the above-mentioned film breakage may occur, and if it is less than 50A, the pressure resistance may be insufficient.

[0081] A region into which the treated liquid flows (hereinafter referred to as “outer region”) is formed outside the hollow fiber membrane bundle 3 between the first adhesive fixing portion 5a and the second adhesive fixing portion 5b formed at both ends of the hollow fiber membrane bundle 3 .

[0082] In addition, if Figure 1 As shown, when the hollow fiber membrane module 1 is vertically arranged, at least one through hole 6 is formed in the second adhesive fixing portion 5b located at the lower side. Figure 2 It is cut along the line AA Figure 1 A cross-sectional view of a hollow fiber membrane module is shown.

[0083] The through hole 6 is formed parallel to the longitudinal direction of the housing 4 and is a hole that connects the above-mentioned outer area with the interior of the cover 8b. Figure 2 As shown, the through hole 6 is provided in a second adhesive fixing portion 5 b between a protective member 7 described later and the inner wall of the housing 4 , and is arranged adjacent to the outer peripheral surface of the hollow fiber membrane bundle 3 .

[0084] The through hole 6 has a partial arc shape having a width in a cross-sectional shape (opening shape) in a direction perpendicular to the longitudinal direction of the housing 4 .

[0085] In addition, in the present disclosure, the partial arc shape having a width is not only Figure 2 The concentric partial arc centered at the center of the hollow portion of the shell 4 (the area divided by the inner wall of the shell) as shown in the figure can be any shape as long as it extends along the circumferential direction of the shell. For example, the contour line constituting the shape can be a wavy or sawtooth shape. In addition, the shape of the end of the partial arc is not particularly limited. For example, it can also be as follows Figure 2 A shape with rounded corners as shown.

[0086] If the opening shape of the through hole 6 is a partial arc with a width, compared with the case where the opening shape is circular, elliptical, polygonal, etc., it is possible to increase the opening area of ​​the through hole 6 while accommodating multiple hollow fiber membranes 2 per unit volume. The number of hollow fiber membranes 2 per unit volume and the amount of treated water supplied to the hollow fiber membrane bundle 3 are balanced to become a larger value, and efficient filtration can be performed.

[0087] Regarding the opening shape of the through hole 6, for example, when four through holes 6 are provided, the central angle of the above-mentioned partial arc centered at the center of the hollow portion of the shell 4 is preferably 45 to 85°, more preferably 60 to 80°, and further preferably 70 to 80°.

[0088] In addition, with the radius of the hollow portion of the shell being r, the width of the partial arc (radial width of the hollow portion of the shell) is preferably 0.05r to 0.25r, more preferably 0.07r to 0.20r, and further preferably 0.09r to 0.12r.

[0089] The number of through holes 6 is not particularly limited, but is preferably a plurality, more preferably 2 to 8, and even more preferably 3 to 6, from the viewpoint of making the sum A of opening areas described below as large as possible.

[0090] When there are a plurality of through holes 6 , the areas of the respective openings (partial arc-shaped cross sections having widths) are preferably substantially the same (within a range of ±5%).

[0091] In addition, when there are multiple through holes 6, the through holes 6 are preferably arranged at equal intervals on the circumference of the circle formed by the opening (partial arc with width). In addition, when there are an even number of through holes 6, each through hole 6 is preferably point-symmetrical about the center of the hollow portion of the shell 4.

[0092] In the cross section in the direction orthogonal to the length direction of the shell 4, the ratio (A / S) of the total opening area A of the through-holes 6 to the area S obtained by subtracting the area of ​​the area divided by the outer peripheral surface of the protective component 7 described later (hereinafter also referred to as the "inner occupied area of ​​the protective component 7") from the area of ​​the area (hollow part) divided by the inner wall of the shell 4 (hereinafter also referred to as the "inner cross-sectional area of ​​the shell 4") is preferably 0.2 to 0.7, more preferably 0.3 to 0.6, and further preferably 0.4 to 0.5. If A / S is within the above range, the amount of water to be treated supplied to the hollow fiber membrane bundle 3 through the through-holes 6 increases, and filtration can be performed efficiently.

[0093] In addition, the hollow portion of each hollow fiber membrane 2 on the side where the through hole 6 is provided is closed by the second adhesive fixing portion 5b, and the hollow portion of each hollow fiber membrane 2 on the side opposite to the side where the through hole 6 is formed is open. When filtering, the treated water flows in from the opening of the cover 8b, and the treated water flows through the through hole 6 and is supplied to the outer area. Then, the treated water supplied to the outer area infiltrates from the outer surface of each hollow fiber membrane 2, and the filtered water flowing through the hollow portion of each hollow fiber membrane 2 is discharged from the opening of the cover 8a, and the discharged water is discharged from the nozzle 12a.

[0094] In addition, the hollow fiber membrane module 1 includes a protective member 7, which is arranged to cover the entire periphery of the outer peripheral surface while being in close contact with the outer peripheral surface of the hollow fiber membrane bundle 3. The protective member 7 is arranged in at least one of an end region of at least a predetermined length from the first adhesive fixing portion 5a toward the second adhesive fixing portion 5b and an end region of at least a predetermined length from the second adhesive fixing portion 5b toward the first adhesive fixing portion 5a, such as Figure 1 As shown, the entire length of the hollow fiber membrane bundle 3 may be covered from the first adhesive fixing portion 5a to the second adhesive fixing portion 5b.

[0095] The protective component 7 is preferably flexible, and its material may include polyolefins such as PE (polyethylene) and PP (polypropylene), fluororesins such as PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer), FEP (tetrafluoroethylene-hexafluoropropylene copolymer (4.6 fluorinated)), and ETFE (tetrafluoroethylene-ethylene copolymer), and super engineering resins such as polysulfone, polyethersulfone, and polyphenylsulfone.

[0096] In addition, the protective component 7 is particularly preferably a component formed of a mesh component into a cylindrical shape. When a component formed of a sheet component into a cylindrical shape instead of a mesh component is used as the protective component 7, in order not to reduce the filtration efficiency, it is preferably provided only at both ends of the hollow fiber membrane bundle 3 or only at one end of the hollow fiber membrane bundle 3, rather than being provided on substantially the entire outer circumference of the hollow fiber membrane bundle 3.

[0097] When the protective member 7 is a mesh member, the wire diameter of the mesh is preferably 0.2 to 1.5 mm, more preferably 0.4 to 1.2 mm, and further preferably 0.5 to 1.0 mm. If the wire diameter is within the above range, it deforms with the expansion, bending, etc. of the hollow fiber membrane bundle 3 caused by the water flow, and the mesh itself is not easily damaged.

[0098] The shape of the opening of the mesh-like protective member 7 is not particularly limited, and examples thereof include a triangle, a quadrilateral (a rhombus, a square, a rectangle, a parallelogram, etc.), and a hexagon.

[0099] The cross-section of the mesh wires constituting the net is not particularly limited, and may be any of a circular shape, a triangular shape, a polygon such as a quadrilateral, an elliptical shape, and the like.

[0100] In order to efficiently supply a large amount of water to be treated to the hollow fiber membrane bundle 3, the opening ratio of the mesh-like protective member 7 is preferably 40 to 90%, more preferably 50 to 80%, and even more preferably 60 to 70%.

[0101] The aperture ratio is a ratio obtained from the area of ​​a portion where no mesh lines are projected when viewed from above.

[0102] Both ends of the protection component 7 are respectively located in the first adhesive fixing portion 5a and the second adhesive fixing portion 5b, and are fixed by the first adhesive fixing portion 5a and the second adhesive fixing portion 5b.

[0103] The protective component 7 is provided at at least one end of the hollow fiber membrane bundle 3 in a state of being in close contact with the outer peripheral surface of the hollow fiber membrane bundle 3. Specifically, the above-mentioned end refers to a first end region R1 including a boundary between the second adhesive fixing portion 5b and the outer region and an area extending from the boundary to the outer region side by a predetermined length L1, and a second end region R2 including a boundary between the first adhesive fixing portion 5a and the outer region and an area extending from the boundary to the outer region side by a predetermined length L2.

[0104] The length L1 from the boundary in the first end region R1 is preferably more than 5 cm. In addition, in the hollow fiber membrane assembly 1 of the present embodiment, as described above, the drain water is discharged from the nozzle 12a, but when the drain water is discharged from the nozzle 12a, the suction force acts on the hollow fiber membrane 2 near the nozzle 12a, and the tendency of breakage increases, and there is a situation where the hollow fiber membrane 2 is easily broken. Therefore, the length L2 from the boundary in the second end region R2 is preferably a length in which the lower end of the second end region R2 is located lower than the lower end of the opening on the inner side of the shell 4 of the nozzle 12a. Thereby, the deformation of the hollow fiber membrane 2 near the nozzle 12a caused by the suction force generated when the drain water is discharged from the nozzle 12a can be suppressed, and the breakage of the hollow fiber membrane 2 can be further suppressed.

[0105] Here, "the state in which the protective component 7 is in close contact with the outer peripheral surface of the hollow fiber membrane bundle 3" means that, when the length of the inner periphery of the protective component 7 is set to L, the number of hollow fiber membranes 2 in contact with the protective component 7 is set to m, and the outer diameter of the hollow fiber membranes 2 filled in the protective component 7 is set to d, md / L is set as the close contact ratio, and the state in which md / L is greater than 0.90 is defined as a close contact state. The higher the close contact ratio, the more preferred it is, and it is more preferred that md / L is greater than 0.95. In addition, when the inner diameter of the protective component 7 is sufficiently large compared to the outer diameter of the hollow fiber membrane 2, theoretically, if the maximum number of hollow fiber membranes 2 at the outermost periphery that can contact the protective component 7 is set to M, then L≈Md holds, and therefore the approximate formula of md / L≈md / Md=m / M holds.

[0106] In addition, the contact between the protective component 7 and the hollow fiber membrane 2 means that the hollow fiber membrane 2 arranged on the outermost part of the hollow fiber membrane bundle 3 is in contact with the protective component 7 at at least one point in the thickness direction of the first adhesive fixing part 5a and the second adhesive fixing part 5b (the length direction of the hollow fiber membrane 2).

[0107] In the hollow fiber membrane assembly 1 of the present embodiment, when the sum of the opening areas of the through holes 6 is set to A, the sum of the opening areas of the hollow portion of the hollow fiber membrane 2 is set to B, and the opening area of ​​the opening portion of the cover 8a, 8b is set to C, the relationship between A, B, and C is 0.5<A / B<1.5, and 0.5<C / B<1.5. If A / B and C / B are within the above range, the concentration of stress on a specific part is reduced, and the uniformity of the pressure distribution and velocity distribution of the fluid flowing through the inside of the hollow fiber membrane assembly 1 is improved. As a result, the pressure loss is reduced, and more filtered water can be collected efficiently.

[0108] A / B is more preferably 0.8<A / B<1.2, and still more preferably 0.9<A / B<1.1. Also, C / B is more preferably 0.8<C / B<1.2, and still more preferably 0.9<C / B<1.1.

[0109] In the hollow fiber membrane module of this embodiment, the filtered water volume (permeate volume) of each module is preferably 10m 3 / h or more, more preferably 12m 3 / h or more, more preferably 16m 3 When the amount of filtered water per module is within the above range, it can be suitably used as a final filtration membrane module for ultrapure water used for cleaning in the manufacture of silicon wafers, LSIs, liquid crystals, etc.

[0110] [Manufacturing method of external pressure type hollow fiber membrane module]

[0111] The manufacturing method of the external pressure type hollow fiber membrane assembly of this embodiment is characterized in that the first straightening cylinder 11a and the second straightening cylinder 11b are installed on the shell 4, and after the hollow fiber membrane bundle 3 covered by the protective component 7 is inserted into the shell 4, a casting fixture is installed on the approximately disc-shaped surface in a manner such that the convex portion is located between the protective component 7 and the shell 4, and the casting fixture has at least one convex portion with a cross-section parallel to the approximately disc-shaped surface and a partial arc shape with a width. After the gap between the protective component 7 and the shell 4 is filled and cured with a potting material, the casting fixture is removed, so that the outer peripheral surface of the hollow fiber membrane bundle 3 is in a state of close contact with the protective component 7, and at least one through hole 6 is opened on the outside of the protective component 7, and the cross-sectional shape of the through hole in the direction orthogonal to the length direction of the shell 4 is a partial arc shape with a width.

[0112] The method for manufacturing an external pressure type hollow fiber membrane module of this embodiment first arranges a predetermined number of hollow fiber membranes 2 into a bundle to produce a hollow fiber membrane bundle 3. Next, the opening at one end of each hollow fiber membrane 2 of the hollow fiber membrane bundle 3 is sealed with a sealing material.

[0113] Next, the first tubular member 9a and the second tubular member 9b are joined to form the housing 4 at both ends of the third tubular member 10, and the first fairing cylinder 11a and the second fairing cylinder 11b are installed to form the module housing body. Then, the outer peripheral surface of the hollow fiber membrane bundle 3 is wrapped with the protective member 7, and the hollow fiber membrane bundle 3 wrapped with the protective member 7 is inserted into the housing 4 in such a way that the sealed end surface side becomes the second tubular member 9b side.

[0114] Then, a cup-shaped bonding jig (for example, Figure 3 b),

[0115] On the second cylindrical member 9b side, a casting jig (for example, Figure 3 a), the casting jig has at least one arc-shaped convex portion whose cross section is parallel to the substantially disc-shaped surface, and the first tubular member and the second tubular member are fluid-tightly restrained with the respective bonding jigs by a known method. At this time, by inserting a jig having the convex portion (e.g., Figure 3 The arc-shaped portion of a) makes the outer peripheral surface of the hollow fiber membrane bundle 3 and the protective member 7 in close contact. The convex portion of the casting jig also becomes a part of the mold of the through hole 6. As described later, after the potting material is solidified, the through hole 6 is formed by removing the casting jig.

[0116] In addition, as required, as an offset limiting member, a cross plate (a member formed by combining or integrally forming two plates in a manner such that the cross section in a direction perpendicular to the height direction becomes a cross shape) may be provided in the hollow fiber membrane bundle 3 in such a manner that the height direction of the cross plate becomes the length direction of the hollow fiber membrane bundle 3. The cross plate is preferably of the same composition as the potting material.

[0117] Next, the first adhesive fixing portion 5a and the second adhesive fixing portion 5b are formed by injecting a potting material into both ends of the housing 4. At this time, the opening of the hollow portion of the hollow fiber membrane bundle 3 on the second cylindrical member 9b side is sealed by the potting material. Thereafter, the through hole 6 is formed by removing the casting jig.

[0118] In order to bond and fix the hollow fiber membrane bundle 3 to the shell 4, centrifugal bonding or static bonding can be performed. Centrifugal bonding is to bond the shell 4 containing the hollow fiber membrane bundle 3 while rotating it in the horizontal direction in a state where the nozzles 12a and 12b are facing upward in the vertical direction. Static bonding is to configure the length direction of the shell 4 in the vertical direction and inject the potting material from the lower end of the shell 4. Centrifugal bonding can bond both ends of the hollow fiber membrane bundle 3 at the same time. In addition, since the coating layer on the outer surface of the hollow fiber membrane bundle 3 can be uniform, it is not easy to cause membrane rupture. On the contrary, a large amount of equipment investment and electricity for high-speed rotation are required. On the other hand, static bonding requires bonding side by side, so the time required for bonding increases, but does not require large-scale equipment investment and can be implemented with a simple clamp. In addition, after the potting material is cured, it can be heated by an oven or the like as needed to promote curing.

[0119] Next, after confirming that the potting material in the housing 4 is solidified, the first tubular member side 9a is opened by removing the adhesive fixing portion forming container and the sealing material (for example, by cutting off the end of the first adhesive fixing portion 5a). The second tubular member 9b side is opened by removing the adhesive fixing portion forming container and the casting jig, so that the through hole 6 with an arc-shaped opening shape can be formed.

[0120] Finally, the covers 8a and 8b are respectively installed on the two ends of the shell 4 to which the hollow fiber membrane bundle 3 is bonded and fixed via the O-rings 14, and after being fastened by the nuts 13, leakage inspection and trial operation are carried out to confirm that it can be manufactured in accordance with regulations, thereby completing the hollow fiber membrane assembly 1.

[0121] Example

[0122] Hereinafter, the present embodiment will be described with reference to specific examples and comparative examples, but the present embodiment is not limited thereto.

[0123] Hereinafter, the measuring methods and the testing methods used in the Examples and Comparative Examples will be described.

[0124] (1) Leakage inspection

[0125] The external pressure type hollow fiber membrane modules of Examples and Comparative Examples were leak-checked as follows.

[0126] That is, after removing the cap on the side where the filtered water is collected (two caps in Comparative Example 1 and one cap in other cases), immerse the hollow fiber membrane module in a water tank so that the inside of the hollow fiber membrane module is filled with water. Next, seal the cap on the side where the water is supplied (a nozzle in Comparative Example 1), and apply an air pressure of 0.3 [MPa] from the nozzle for discharging water. Observe the end face of the hollow fiber membrane on the side where the filtered water is collected (two end faces in Comparative Example 1 and one end face in other cases), and investigate the occurrence of leakage by whether continuous bubbles are generated in the hollow part.

[0127] (2) Flow analysis

[0128] For the examples and comparative examples, flow analysis was performed using the thermal fluid analysis software "PHOENICS" produced by CHAM (Control Heat and Momentum Limited) as simulation software and the Chen-KimKE equation as a calculation equation. The fluid was 20°C water.

[0129] As a simulation model of an embodiment, Figure 5 As shown in (a), a semi-cylindrical space with a radius equal to the inner diameter of the shell is drilled in a rectangular parallelepiped (1.284m in the x direction × 0.088m in the y direction × 0.223m in the z direction), an inlet is set at one end and an outlet is set at the other end. Figure 5 (a) is a 3D model in which the surface parallel to the XZ plane is divided into 1 / 2 (1 / 2 model).

[0130] The mesh division of the simulation model is performed by dividing the x direction (length direction) into 300, the y direction (depth direction) into 30, and the z direction (height direction) into 70, so that the total number of mesh units is set to 630,000.

[0131] The number of SWEEPs (number of calculation repetitions) was 4000, and the amount of water flowing in from the end (inlet) of the cylinder was 2.64×10 -3 m 3 / s (1 / 2 model) The water pressure and velocity of the 1 / 2 model are simulated. The resistance values ​​of the water-containing porous body corresponding to the hollow fiber membrane bundle in the x-direction, y-direction, and z-direction are 0.4, respectively, and the porosity is 0.7.

[0132] In addition, in order to simulate the final filtration of ultrapure water assumed as the purpose of the external pressure type hollow fiber membrane module of this embodiment, it is performed as a full filtration (no discharge water). In the final filtration of ultrapure water, since the treated water itself is already very clear water, the discharge water is a flow rate of about several percent of the treated water, which can be said to be within the range of error in the simulation.

[0133] The simulation results of pressure and velocity are shown in Figure 6 , 7 As shown in the figure, the distribution of pressure and speed is represented by light and dark, the direction of water flow is represented by arrows, and the size of pressure and speed is represented by the length of arrows. That is, the longer the arrow, the greater the pressure and speed.

[0134] <Production Example 1>

[0135] The external pressure hollow fiber membrane modules used in Examples 1 and 2 were manufactured as follows (refer to Figure 1 ).

[0136] 11600 polysulfone hollow fiber membranes (produced by Asahi Kasei Corporation) are bundled to form a hollow fiber membrane bundle, which is inserted into a polyethylene net formed into a cylindrical shape with an inner diameter of 138mm (wire diameter 0.45mm, opening rate 55%, equivalent to a protective component). The hollow fiber membrane bundle inserted into the net is inserted into a shell having a first and second tubular component (inner diameter of 168mm) and a third tubular component (inner diameter 154mm), and the first and second straightening cylinders (inner diameter 140mm) are installed on the inner sides of the first and second tubular components, respectively. In addition, the first tubular component has a discharge nozzle with an inner diameter of 40mm, and the second tubular component has a sealed nozzle. A hollow fiber membrane with a molecular weight cutoff of 6000, an inner diameter of 0.6mm, and an outer diameter of 1.00mm is used.

[0137] The hollow portion of the hollow fiber membrane end portion on the first tubular member side is sealed with a sealing material, and at the same time, as an offset limiting member, a cross plate (a member in which two plates of 63 mm in height, 136 mm in width, and 5 mm in thickness are joined in a manner such that the cross section in a direction perpendicular to the height direction becomes a cross shape) having the same composition as the potting material described later is arranged in the hollow fiber membrane bundle in such a manner that the height direction of the cross plate becomes the length direction of the hollow fiber membrane bundle. Furthermore, a sealing material is installed at the end portion of the first tubular member. Figure 3 (b) A centrifugal casting cup of the shape shown.

[0138] By installing at the end of the second cylindrical member Figure 3 (a) is a high-density polyethylene casting jig, so that after the potting material is cast, four openings with partial arcs (opening area 800mm) are formed. 2, center angle: 80 °, width: 8mm) through hole, the arc-shaped opening of the part has a width. Afterwards, the centrifugal casting cup is installed in the same manner as the end of the first tubular component.

[0139] Next, install the potting material introduction tube in the cups installed on the first and second cylindrical parts respectively. With the nozzle facing vertically upward, fix the housing horizontally on the centrifuge frame, and rotate the housing horizontally to inject the potting material into the first and second cylindrical parts of the housing. A two-component curing epoxy resin is used as the potting material. The curing reaction of the potting material is carried out, and the rotation of the centrifuge is stopped at the moment when the fluidization stops. Remove the housing from the centrifuge frame and heat it to 90°C in an oven to completely cure it.

[0140] On the first cylindrical part, the cup was removed and the outer end of the cured potting material was cut off to open the hollow part of the hollow fiber membrane. On the second cylindrical part, the cup and casting fixture were removed to form four partially arc-shaped openings (opening area 800mm 2 ) through hole, the arc-shaped opening of this part has a width.

[0141] Next, the opening diameter of 66 mm was inserted through the O-ring. Figure 1 The covers of the shape shown are fixed to both sides of the housing in a liquid-tight manner by tightening with nuts, thereby obtaining an external pressure type hollow fiber membrane module.

[0142] The total opening area A of the through holes of the external pressure type hollow fiber membrane module is 3200 mm 2 The total opening area B of the hollow part of the hollow fiber membrane is 3280 mm 2 The opening area C of the cover opening is 3421mm 2 The area S obtained by subtracting the inner area occupied by the net (protective component) from the inner cross-sectional area of ​​the shell (second cylindrical component) is 7210 mm 2 . Therefore, A / B is 0.98, C / B is 1.04, and A / S is 0.44.

[0143] <Production Example 2>

[0144] The external pressure type hollow fiber membrane module used in Example 5 was manufactured in the same manner as in Manufacturing Example 1 except that a hollow fiber membrane with a molecular weight cutoff of 10,000, an inner diameter of 0.6 mm, and an outer diameter of 1.00 mm was used (see Figure 1 ).

[0145] <Example 1>

[0146] The external pressure type hollow fiber membrane module of the above-mentioned manufacturing example 1 was installed in a manner such that the first cylindrical member side was the upper side in the vertical direction and the second cylindrical member side was the lower side in the vertical direction. Figure 4 (a) The evaluation device shown in Figure 4 (a), omitting the water tank, pump, etc.) The following operation is performed: 3 / h flow rate of water is supplied from the through hole, with a flow rate of 0.4m 3 / h flow rate of water discharged from the nozzle, to obtain 12m 3 At this time, the fluid velocity (linear velocity) at each part calculated based on the opening area is 1.07 m / s at the through hole, 1.02 m / s at the hollow part of the hollow fiber membrane, 1.00 m / s at the opening of the cover on the water supply side, and 0.97 m / s at the opening of the cover on the filtered water side.

[0147] The above operating conditions were maintained and the system was continuously operated, with a leakage check once a day for about 5 minutes. After one year, no leakage due to rupture of the hollow fiber membrane occurred.

[0148] <Example 2>

[0149] Except for the operating conditions shown in Table 1, the operation was continued in the same manner as in Example 1, and a leakage inspection was performed once a day for about 5 minutes each time.

[0150] Since no leakage due to rupture of the hollow fiber membrane occurred even after 30 days from the start of operation, the supply water volume was increased by 30% from the 31st day and the operation was continued (supply water volume 20.6m 3 / h, water discharge 0.6m 3 / h, water flow rate 20m 3 / h), and leakage was confirmed on day 91 due to a break in one of the hollow fiber membranes. After that, the broken hollow fiber membrane was repaired and the operation was continued. No leakage occurred until day 150, and the operation was terminated.

[0151] <Example 3>

[0152] As a simulation model following the specifications of the external pressure type hollow fiber membrane module of the above-mentioned manufacturing example 1, Figure 5 The calculation model shown in (a) was used for flow analysis. Figure 5 (b) is a diagram showing the structure near the entrance.

[0153] In the same manner as in Manufacturing Example 1, a through hole having a partially arc-shaped cross section (see Figure 5 (b)) The opening area is set to 800 mm 2 The opening inner diameter of the inlet 22 and the outlet 21 is set to 66 mm, and 11,600 hollow fiber membranes with an inner diameter of 0.6 mm and an outer diameter of 1.00 mm are used, and a trial calculation is performed as full filtration (no discharge water). The arc-shaped cross section has a width. By subtracting the inner cross-sectional area of ​​the net filled with the hollow fiber membrane of 138 mm from the occupied cross-sectional area calculated by the diameter of 168 mm, which is equivalent to the inner diameter of the second tubular component, the area S obtained by subtracting the inner occupied area of ​​the net (protective component) from the inner cross-sectional area of ​​the shell (second tubular component) is 7210 mm. 2 .

[0154] Table 1 shows the linear velocity, A / B, C / B, and A / S at each location at this time.

[0155] In addition, the results of pressure distribution and velocity distribution are shown in Figure 6 (a) and 6(b). It can be seen that the pressure distribution and velocity distribution have gentle slopes and less pressure loss.

[0156] <Example 4>

[0157] In addition to setting the opening area of ​​the through hole with a circular arc cross section to 750 mm 2 (Central angle: 75°, width: 8 mm) and flow analysis was performed in the same manner as in Example 3 except that the inner diameters of the openings of the inlet 22 and the outlet 21 were set to 52.5 mm.

[0158] Table 1 shows the linear velocity, A / B, C / B, and A / S at each location at this time.

[0159] In addition, the results of pressure distribution and velocity distribution are shown in Figure 7 Compared with Example 3, the distribution gradient is large, but it is a distribution that can withstand practical use.

[0160] <Example 5>

[0161] Except for the operating conditions shown in Table 1, the operation was continued in the same manner as in Example 1, and a leakage inspection was performed once a day for about 5 minutes each time.

[0162] Although leakage due to the breakage of the hollow fiber membrane did not occur even after 3 days from the start of operation, leakage due to the breakage of four hollow fiber membranes was confirmed on the 4th day. After that, the broken hollow fiber membrane was repaired and the operation was continued, and leakage due to the breakage of three new hollow fiber membranes different from the hollow fiber membrane broken on the 4th day was confirmed on the 12th day, and the operation was terminated.

[0163] <Comparative Example 1>

[0164] The hollow fiber membrane module disclosed in Example 1 of Patent Document 1 is manufactured. Figure 4In the evaluation device shown in (b), similarly to Example 1 of Patent Document 1, the pipe 10a is installed in a manner such that the pipe 11a is located at the upper side in the vertical direction and the pipe 11a is located at the lower side in the vertical direction. Figure 4 (b), the water tank, pump, etc. are omitted). In this hollow fiber membrane module, the gap portion between the outer wall of the rectifying cylinder 28 and the inner wall of the main body 13, whose cross-sectional shape is concentric with the longitudinal direction of the shell orthogonal to the longitudinal direction of the shell, is regarded as a portion equivalent to the through hole in the external pressure type hollow fiber membrane module of the embodiment.

[0165] According to the numerical values ​​disclosed in Patent Document 1 and the Figure 1 , 3 The dimensions of each part are calculated by proportional calculation. Thus, the outer diameter and inner diameter of the concentric circular opening of the above-mentioned gap portion are calculated to be 154 mm and 149.6 mm respectively, and the area equivalent to the total opening area A of the through hole is calculated to be 1049 mm 2 Similarly, the diameter of the hollow part of the hollow fiber membrane is 0.6 mm, and the number of fibers is 11,600. Therefore, the total opening area B of the hollow part of the hollow fiber membrane is calculated to be 3,280 mm. 2 In addition, since the opening diameter of the cover 10 corresponding to the filtered water discharge side cover in the present invention is 20 mm by proportional calculation, the opening area C on the filtered water side is calculated to be 314 mm. 2 Since the diameter of the opening 21a of the lower nozzle 21 of the treated water supply side cover in the present invention is 58mm, the opening area C of the treated water supply side is calculated to be 2642mm 2 In addition, based on the inner diameter of the header 15 of 162 mm and the outer diameter of the drift suppression unit 29 of 145.2 mm calculated by proportional calculation, the area S obtained by subtracting the inner occupied area of ​​the protective component (net-shaped drift suppression unit 29) from the inner cross-sectional area of ​​the shell (header 15) is 4053 mm. 2 .

[0166] Table 1 shows the linear velocity, A / B, C / B, and A / S at each location at this time.

[0167] The membrane module was continuously operated under the same operating conditions as in Example 2, and a leakage inspection was performed once a day for about 5 minutes.

[0168] Since no leakage due to rupture of the hollow fiber membrane occurred even after 30 days from the start of operation, the supply water volume was increased by 30% from the 31st day and the operation was continued (supply water volume 20.6m 3 / h, water discharge 0.6m 3 / h, water flow rate 20m 3 / h), and leakage due to one broken hollow fiber membrane was confirmed on day 49. After that, the broken hollow fiber membrane was repaired and the operation was continued. However, leakage due to one broken hollow fiber membrane was also confirmed on day 77, and the operation was terminated.

[0169] <Comparative Example 2-1>

[0170] The external pressure type hollow fiber membrane module disclosed in Example 1 of Patent Document 3 was manufactured according to the manufacturing method described in Patent Document 3. Figure 4 In the evaluation device shown in (a), similarly to Example 1 of Patent Document 3, the pipe 10a is installed in a manner such that the pipe 11a is located at the upper side in the vertical direction and the pipe 11a is located at the lower side in the vertical direction. Figure 4 (a), water tank, pump, etc. are omitted). The hollow fiber membrane used was a hollow fiber membrane with an outer diameter of 1.0 mm and an inner diameter of 0.6 mm as in the above-mentioned manufacturing example 1, and the number of hollow fiber membranes was set to 5400, which was based on the area occupied by the hollow fiber membrane in the cross section perpendicular to the length direction in the membrane module of Example 1 of Patent Document 3 (outer diameter basis).

[0171] According to the numerical values ​​disclosed in Patent Document 3 and the Figure 1 The dimensions of each part are calculated by proportional calculation. Since there are five through holes with a circular opening shape of 11 mm in diameter, the total opening area A of the through holes is 475 mm. 2 The inner diameter of the hollow part of the hollow fiber membrane is 0.6 mm, and the number of fibers is 5400. Therefore, the total opening area B of the hollow part of the hollow fiber membrane is 1527 mm 2 , the diameter of the lid opening is 31.6 mm, so the calculated opening area C of the lid is 784 mm 2 In addition, by proportional calculation, the inner diameter of the shell (first tubular component 51) is 96.8 mm, so the area S obtained by subtracting the inner area occupied by the protective component (net-shaped protective component 8, inner diameter 80 mm) from the inner cross-sectional area of ​​the shell (first tubular component 51) is 2333 mm 2 .

[0172] The following operation was performed in the same manner as in Example 1 of Patent Document 3: 3 / h flow rate of water is supplied from the through hole, with a flow rate of 0.4m 3 / h flow rate of water discharged from the nozzle, to obtain 3.1m 3 / h of filtered water.

[0173] Table 1 shows the linear velocity, A / B, C / B, and A / S at each location at this time.

[0174] The above-mentioned operating conditions were maintained and the operation was continued, and a leakage check was performed once a day for about 5 minutes each time. It was confirmed that leakage occurred after 6 months due to the breakage of one hollow fiber membrane. After that, the broken hollow fiber membrane was repaired and the operation was continued. After 7 months, it was confirmed that leakage occurred due to the breakage of one hollow fiber membrane different from the hollow fiber membrane that broke after 6 months, and the operation was terminated. After that, the broken hollow fiber membrane was repaired and the operation was continued. After 9 months, it was confirmed that leakage occurred due to the breakage of two hollow fiber membranes different from the hollow fiber membranes that broke after 6 months and 7 months, and the operation was terminated. After disassembling the hollow fiber membrane assembly and confirming the location of the leakage, a total of four hollow fiber membranes were broken at a position within a range of 20 to 50 mm in the length direction from the inner end of the bonding and fixing part (potting part) near the through hole.

[0175] <Comparative Example 2-2>

[0176] The external pressure type hollow fiber membrane module of Comparative Example 2-1 leaked in a short period of time compared to the external pressure type hollow fiber membrane module of Example 1 of Patent Document 3. Therefore, as a simulation model following the specifications of the external pressure type hollow fiber membrane module of Comparative Example 2-1, a simulation model was constructed. Figure 8 The calculation model shown in (a) was used for flow analysis. Figure 8 (b) is a diagram showing the structure near the entrance.

[0177] like Figure 8 As shown in (a), a semi-cylindrical space with a radius equal to the inner diameter of the shell is drilled in a rectangular parallelepiped (1.375m in the x direction × 0.052m in the y direction × 0.152m in the z direction), an inlet is set at one end and an outlet is set at the other end. Figure 8 (a) is a 3D model in which the surface parallel to the XZ plane is divided into 1 / 2 (1 / 2 model).

[0178] As in Comparative Example 2-1, the inner diameter of the housing (first tubular member 51) is 96.8 mm by proportional calculation, and the area S obtained by subtracting the inner area occupied by the protective member (net-shaped protective member 8, inner diameter 80 mm) from the inner cross-sectional area of ​​the housing (first tubular member 51) is 2333 mm. 2 .

[0179] The mesh division of the simulation model is performed by dividing the x direction (length direction) into 340, the y direction (depth direction) into 20, and the z direction (height direction) into 55, so that the total number of mesh units is set to 374,000.

[0180] The number of SWEEPs was 4000, and the amount of water flowing in from the end of the cylinder (inlet 32) was 4.86×10 -4 m 3 / s(1 / 2 model, same as 3.5m 3 The water pressure and velocity of the 1 / 2 model were simulated in the case of 1 / 2 % water per hour. The resistance values ​​of the water-containing porous body corresponding to the hollow fiber membrane bundle in the x-, y-, and z-directions were 0.4, and the porosity was 0.7.

[0181] The velocity distribution results are as follows: Fig. 9 (a) and 9(b). Fig. 9 (a) is the distribution diagram observed from the length direction of the simulation model. Fig. 9 (b) is a distribution diagram observed from a direction perpendicular to the length direction of the simulation model. Fig. 9 (a) and Fig. 9 (b) It can be seen that the water supplied from the through hole is in a jet flow state. The main reason for the jet flow state is considered to be the shortage of (the opening area of) the through hole.

[0182] In Example 1 of Patent Document 3, no leakage occurred after one year of continuous operation, while the main reason for the leakage in Comparative Example 2-1 is believed to be the difference in durability of each membrane fiber against the jet flow. That is, the outer diameter / inner diameter of the hollow fiber membrane used in Example 1 of Patent Document 3 = 1.35 mm / 0.75 mm (cross-sectional area of ​​the thick wall portion = 0.99 mm 2 ), while in Comparative Example 2-1 it is 1.00mm / 0.60mm (cross-sectional area of ​​thick wall portion = 0.5mm 2 ), so it can be considered that the hollow fiber membrane of Comparative Example 2-1 has insufficient durability against the vibration caused by the above-mentioned jet.

[0183] <Comparative Example 3>

[0184] As a simulation model following the specifications of the external pressure type hollow fiber membrane module disclosed in Example 1 of Patent Document 2, Fig.10 The calculation model shown in (a) was used for flow analysis. Fig.10 (b) is a diagram showing the structure near the entrance.

[0185] like Fig.10 As shown in (a), a semi-cylindrical space having a radius equal to the inner diameter of the shell is provided in a rectangular parallelepiped (1.284m in the x direction × 0.088m in the y direction × 0.223m in the z direction), an inlet 42 is provided at one end, and an outlet 41 is provided at the other end. Fig.10(a) is a 3D model in which the surface parallel to the XZ plane is divided into 1 / 2 (1 / 2 model).

[0186] The simulation model was meshed by dividing the x direction (length direction) into 300, the y direction (depth direction) into 30, and the z direction (height direction) into 70, so that the total number of mesh cells was set to 630,000.

[0187] According to the numerical values ​​disclosed in Patent Document 2 and the Figure 1 The dimensions of each part are calculated by proportional calculation. As a component equivalent to a through hole, it is considered to have an annular opening with an outer diameter of 160 mm and an inner diameter of 151.4 mm. According to the disclosure of an outer diameter of 1.2 mm, the inner and outer diameter ratio of the hollow fiber membrane used in the above embodiment is applied, and the inner diameter of the hollow fiber membrane is considered to be 0.72 mm, and 10,800 are used as disclosed. The inner diameter of the opening of the inlet 42 and the outlet 41 is 39 mm.

[0188] In addition, the area S obtained by subtracting the occupied cross-sectional area equivalent to the outer diameter of the outer layer mesh tube 3 (calculated as 147 mm through proportional calculation) from the occupied cross-sectional area equivalent to the inner diameter of the head 160 mm is obtained by subtracting the inner occupied area of ​​the protective component (outer layer mesh tube 3) from the inner cross-sectional area of ​​the shell, which is calculated to be 3135 mm.

[0189] The number of SWEEPs was 4000, and the amount of water flowing in from the end (inlet) of the cylinder was 2.64×10 -3 m 3 / s (1 / 2 model) The water pressure and velocity of the 1 / 2 model are simulated. The resistance values ​​of the water-containing porous body corresponding to the hollow fiber membrane bundle in the x-direction, y-direction, and z-direction are 0.4, respectively, and the porosity is 0.7.

[0190] The linear speed, A, B, C, A / B, C / B, and A / S at each position at this time are shown in Table 1.

[0191] In addition, the results of pressure distribution and velocity distribution are shown in Fig.11 (a) and 11(b). Compared with Examples 3 and 4, the pressure inside the supply section (equivalent to the inside of the sealing section 4 side of the cover 15 of Patent Document 2) and the inside of the filtered water collection section (equivalent to the vicinity of the permeate outlet 14 of the cover 16 of Patent Document 2) is higher, and a large pressure loss is observed when the treated water is supplied to the hollow fiber membrane bundle and after the filtered water is discharged from the hollow fiber membrane bundle. In addition, since the distribution of the maximum pressure values ​​is observed inside the supply section, it is shown that the hollow fiber membrane bundle has an upward effect (in the Fig.11 That is, a force is generated that pushes the entire hollow fiber membrane bundle upward (to the left in (a)). Fig.11(a) is the left side) and there is a concern that the fiber bundle may bend.

[0192] <Comparative Example 4>

[0193] In the calculation model of Comparative Example 3, the concern of buckling is predicted as described above, so Fig.12 As shown in (a) and 12(b), a calculation model in which a baffle plate 53 was further provided in the calculation model of Comparative Example 3 was constructed, and flow analysis was performed under the same conditions as Comparative Example 3. In the baffle plate 53, as a member equivalent to the through hole of the embodiment, a model was adopted in which 16 holes with a diameter of 25 mm were opened along the outer circumference (for the 1 / 2 calculation model, 8 holes were opened in the calculation model).

[0194] Similar to Comparative Example 3, the area S obtained by subtracting the inner occupied area of ​​the protective component (outer layer mesh tube 3) from the inner cross-sectional area of ​​the shell is calculated by subtracting the occupied cross-sectional area equivalent to the outer diameter of the outer layer mesh tube 3 (calculated as 147 mm by proportional calculation) from the occupied cross-sectional area equivalent to the inner diameter of the head 160 mm, and the calculated value is 3135 mm.

[0195] The linear speed, A, B, C, A / B, A / B, and A / S at each position at this time are shown in Table 1.

[0196] In addition, the results of pressure distribution and velocity distribution are shown in Fig.13 The distribution of the maximum pressure value that is concerned about buckling moves from the surface corresponding to the end surface of the sealing portion 4 to the baffle plate inside the supply portion, but the pressure inside the supply portion and the filtered water collection portion is as high as that in Comparative Example 3, and the tendency to produce a large pressure loss is the same.

[0197] <Comparative Example 5>

[0198] An external pressure type hollow fiber membrane module was manufactured in which only the hollow fiber membrane was different from that in Comparative Example 1 (the hollow fiber membrane was the same as that used in Manufacturing Example 2), and was continuously operated in the same manner as in Example 5, with leakage inspections being performed once a day for about 5 minutes each time.

[0199] From the start of the operation, leakage due to the breakage of 7 hollow fiber membranes was confirmed on the first day and a total of 13 on the second day, and the operation was terminated.

[0200] Table 1

[0201]

[0202] Industrial Applicability

[0203] The external pressure type hollow fiber membrane assembly of the present invention has good durability, excellent uniformity of pressure distribution and velocity distribution of the fluid flowing through the interior, and less pressure loss. Therefore, it is particularly suitable for use as the final filtration membrane assembly for ultrapure water used in cleaning during the manufacture of silicon wafers, LSIs, liquid crystals, etc.

[0204] Explanation of symbols

[0205] 1 External pressure hollow fiber membrane module

[0206] 2 Hollow fiber membrane

[0207] 3 Hollow fiber membrane bundle

[0208] 4 Housing

[0209] 5a First bonding and fixing portion

[0210] 5b Second bonding and fixing portion

[0211] 6, 23, 33 through holes

[0212] 7 Protective components

[0213] 8 Cover

[0214] 9a First cylindrical member

[0215] 9b Second cylindrical member

[0216] 10 Third cylindrical member

[0217] 11a The first rectifier tube

[0218] 11b Second rectifier tube

[0219] 12 Nozzle

[0220] 13 Nut

[0221] 14 O-ring

[0222] 21, 31, 41, 51 exit

[0223] Entrance 22, 32, 42, 52

[0224] 53 Blocking plate

Claims

1. An external pressure type hollow fiber membrane module, characterized in that: have: A hollow fiber membrane bundle is formed by bundling a plurality of hollow fiber membranes with one end closed and the other end open; A shell, which is a cylindrical body having at least one nozzle on a side surface, and houses the hollow fiber membrane bundle in such a manner that the closed end of the hollow fiber membrane and the open end of the hollow fiber membrane are respectively oriented toward both end sides in the length direction of the cylindrical body; A first fairing cylinder installed between the open end of the hollow fiber membrane bundle and the end of the shell; A second fairing cylinder installed between the closed end of the hollow fiber membrane bundle and the end of the shell; a first bonding and fixing portion that bonds and fixes the hollow fiber membranes to each other and the hollow fiber membrane bundle to the inner wall of the housing at the end side of the opening of the hollow fiber membrane; A second bonding and fixing portion, which bonds and fixes the hollow fiber membranes to each other and the hollow fiber membrane bundle to the inner wall of the shell on the closed end side of the hollow fiber membrane, and has at least one through hole parallel to the length direction of the shell on the outer periphery of the hollow fiber membrane bundle; a protective member covering the entire periphery of the outer peripheral surface of the hollow fiber membrane bundle in a state of being closely attached to the outer peripheral surface of the hollow fiber membrane bundle in at least one of an end region of at least a predetermined length from the first adhesive fixing portion toward the second adhesive fixing portion and an end region of at least a predetermined length from the second adhesive fixing portion toward the first adhesive fixing portion; as well as A cover having an opening and mounted at both ends of the housing in the longitudinal direction, The through hole is arranged adjacent to the outer peripheral surface of the hollow fiber membrane bundle, and the cross-sectional shape of the through hole in a direction perpendicular to the longitudinal direction of the shell is a partial arc shape having a width. In a cross section in a direction perpendicular to the length direction of the shell, The ratio A / S of the total opening area A of the through holes to the area S, i.e., the area obtained by subtracting the area of ​​the area divided by the outer peripheral surface of the protection member from the area of ​​the area divided by the inner wall of the housing, is 0.4 to 0.5; The sum of the opening areas of the through holes is set to A, the sum of the opening areas of the hollow parts of the hollow fiber membranes is set to B, the opening area of ​​the opening part of the cover is set to C, and the relationship between A, B, and C is 0.

9. The protective component is arranged between the hollow fiber membrane bundle and the through holes and in contact with the hollow fiber membrane bundle and the through holes. The C / B is 0.8 <C / B<1.2。 2. The external pressure type hollow fiber membrane module according to claim 1, wherein: The C / B is 0.9 <C / B<1.1。 3. The external pressure type hollow fiber membrane module according to claim 2, wherein: The inner diameter of the hollow fiber membrane is 100 to 3000 μm, and the outer diameter is 200 to 4000 μm.

4. The external pressure type hollow fiber membrane module according to claim 1, wherein: The inner diameter of the hollow fiber membrane is 400-1000 μm, and the outer diameter is 500-2000 μm.

5. The external pressure type hollow fiber membrane module according to claim 1, wherein: The hollow fiber membrane bundle contains 5000 to 20000 hollow fiber membranes.

6. The external pressure type hollow fiber membrane module according to claim 1, wherein: The hollow fiber membrane bundle contains 9000 to 13000 hollow fiber membranes.

7. The external pressure type hollow fiber membrane module according to claim 6, wherein: The hollow fiber membrane is made of polysulfone.

8. The external pressure type hollow fiber membrane module according to claim 1, wherein: The molecular weight cut-off of the hollow fiber membrane is greater than 6,000.

9. The external pressure type hollow fiber membrane module according to claim 1, wherein: ​ 10. The external pressure type hollow fiber membrane module according to any one of claims 1 to 9, wherein: The protection member is disposed over the entire range from the first adhesively fixed portion to the second adhesively fixed portion.

11. The external pressure type hollow fiber membrane module according to any one of claims 1 to 9, wherein: The protective member is a member obtained by forming a mesh-like member into a cylindrical shape.

12. The external pressure type hollow fiber membrane module according to claim 11, wherein: The wire diameter of the mesh component is 0.2-1.5 mm, and the opening ratio is 40-90%.

13. The external pressure type hollow fiber membrane module according to claim 12, wherein: The wire diameter is 0.5-1.0 mm.

14. The external pressure type hollow fiber membrane module according to claim 12, wherein: The opening ratio is 60-70%.

15. The external pressure type hollow fiber membrane module according to any one of claims 1 to 9, wherein: The filtered water volume of each component is 10m 3 / h or more.

16. The external pressure type hollow fiber membrane module according to any one of claims 1 to 9, wherein: The opening of at least one of the covers has a structure in which it is sealed and fixed by a gasket, and the gasket has an inner diameter that is the same as that of the opening.

17. A method for manufacturing an external pressure type hollow fiber membrane module according to any one of claims 1 to 16, characterized in that: The first straightening cylinder and the second straightening cylinder are installed on the shell. After the hollow fiber membrane bundle covered by the protective component is inserted into the shell, a casting fixture having at least one protrusion is installed on the approximately disc-shaped surface in such a way that the protrusion is located between the protective component and the shell. The cross-section of the protrusion parallel to the approximately disc-shaped surface is a partial arc with a width. After the gap between the protective component and the shell is filled and cured with a potting material, the casting fixture is removed so that the outer peripheral surface of the hollow fiber membrane bundle is in a close contact with the protective component, and at least one through hole is opened on the outer side of the protective component. The cross-section of the through hole in a direction perpendicular to the length direction of the shell is a partial arc with a width.

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