JP2015182056A - hollow fiber membrane module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hollow fiber membrane module which can prevent breakage of the hollow fiber membrane in a periphery of a boundary with a sealed part, and can prevent breakage caused by collision of the hollow fiber membrane with a net cylinder.SOLUTION: The hollow fiber membrane module includes: a housing 10 having an original liquid inlet 12 and a penetrated-liquid outlet 14; a plurality of hollow fiber membranes 1 housed in the housing 10; a plurality of inner layer net cylinders 2 which are formed by dividing the hollow fiber membranes 1 into plural parts and bundling; a single or a plurality of outer layer net cylinders 3 which bundle the plurality of the inner layer net cylinders 2; and a sealing part 4 which is arranged at least on one end side of the hollow fiber membranes and prevents mixture of an original liquid side flow passage and a penetration side flow passage. The outer layer net cylinder 3 has a thickness of more than 1.0 mm and a net fiber diameter of 0.9-5.0 mm. The inner layer net cylinder 2 has a thickness of 1.0 mm or less and a net fiber diameter of 0.1-1.0 mm.

Description

  The present invention provides a plurality of hollow fiber membranes, a housing that accommodates the hollow fiber membranes, and a seal that is provided at least on one end side of the hollow fiber membranes to prevent mixing of the stock solution side channel and the permeate side channel The hollow fiber membrane module which has a part.

  Conventionally, for example, as shown in FIG. 6, the hollow fiber membrane module has a sealing portion 4 a in which one end of a plurality of hollow fiber membranes 1 is sealed with a casting agent in the housing 10, and the other end is in an open state. The sealing part 4b bundled with the casting agent has a structure that prevents mixing of the stock solution side channel and the permeate side channel. In such a hollow fiber module, it is necessary to prevent damage to the hollow fiber that occurs during handling of the hollow fiber bundle during manufacture.

  Therefore, in general, in order to prevent damage to the hollow fiber, the hollow fiber is put into a net tube made of a hard net to form a bundle of hollow fiber membranes, and the ends thereof are fixed together with a casting agent. By using a net cylinder made of a hard net, the net cylinder is not deformed even when the weight of the hollow fiber membrane or the casting resin is applied, so that the hollow fiber is not damaged during handling.

  Further, when bundling a plurality of hollow fiber membranes, by using a plurality of inner layer net cylinders that divide the hollow fiber membranes into a plurality of bundles and an outer layer net cylinder that bundles a plurality of the inner layer net cylinders, A hollow fiber membrane module having a double holding structure is also known (see, for example, Patent Documents 1 and 2).

JP-A-6-341 JP-A-8-206468

  However, since the inner layer net cylinder and the outer layer net cylinder described in the above publication are not particularly different in thickness and the like, the advantage of making the holding structure a double structure cannot be obtained sufficiently. For example, when both the net cylinders have both increased rigidity, they cannot follow the movement of the hollow fiber membrane inside, so if a high flow rate occurs near the stock solution outlet provided on the side of the housing, It has been found that the momentum of the flow causes the hollow fiber membrane to move with a strong force and collide with the inner layer net tube, and the hollow fiber membrane may be damaged.

  In addition, when both of the net cylinders have low rigidity, if a high flow rate is generated near the stock solution discharge port, the overall movement of the hollow fiber membrane increases, so that the hollow fiber membrane is near the boundary with the sealing portion. May be damaged. When such a hollow fiber membrane breakage occurs, the stock solution leaks into the permeate, and there is a problem that the removal target substance such as fine particles on the permeate side increases and the separation inhibition rate decreases.

  Accordingly, an object of the present invention is to provide a hollow fiber membrane module that can prevent breakage of the hollow fiber membrane in the vicinity of the boundary with the sealing portion, and can prevent damage due to collision of the hollow fiber membrane with the net cylinder. .

The above object can be achieved by the present invention as described below.
That is, the hollow fiber membrane module of the present invention includes a housing having a stock solution inlet and a permeate outlet, a plurality of hollow fiber membranes accommodated in the housing, and a plurality of bundles of the hollow fiber membranes divided into a plurality of bundles. An inner layer net cylinder, one or a plurality of outer layer net cylinders that bundle a plurality of inner layer net cylinders, and a seal that is provided at least on one end side of the hollow fiber membrane to prevent mixing of the stock solution side channel and the permeate side channel The outer layer net cylinder has a thickness exceeding 1.0 mm, the net yarn diameter is 0.9 mm or more and 5.0 mm or less, and the inner layer net cylinder has a thickness of It is 1.0 mm or less, and a net yarn diameter is 0.1 mm or more and 1.0 mm or less.

  According to the hollow fiber membrane module of the present invention, since the thickness of the outer layer net cylinder exceeds 1.0 mm and the net yarn diameter is 0.9 mm or more and 5.0 mm or less, the outer layer net cylinder is hollow with a relatively high rigidity. Since the entire movement of the yarn membrane can be reduced, the hollow fiber membrane can be effectively prevented from being damaged near the boundary with the sealing portion. Moreover, since the thickness of the inner layer net cylinder is 1.0 mm or less and the net yarn diameter is 0.1 mm or more and 1.0 mm or less, the inner layer net cylinder has a structure in which the hollow fiber membranes are bundled with a relatively low rigidity. . For this reason, since the inner layer net tube can follow the movement of the hollow fiber membrane inside, even if a high flow rate is generated near the stock solution outlet, the fluid flow momentum moves the hollow fiber membrane with a strong force to The impact when colliding with the net cylinder is reduced, and the hollow fiber membrane can be effectively prevented from being damaged.

  In the above, it is preferable that one end of the hollow fiber membrane is sealed without being opened by the casting agent, and the other end is sealed with the casting agent in an opened state. In this structure, by allowing the stock solution to permeate from the outside of the hollow fiber membrane, the permeated solution after membrane separation can flow to one end side and be discharged.

  The outer layer net tube preferably has a net yarn extending in the axial direction, and the inner layer net tube preferably has a shape in which net yarns extending in a direction inclined with respect to the circumferential direction intersect. If the inner layer net tube has a shape in which net yarns extending in a direction inclined with respect to the circumferential direction intersect, it is more easily deformed by bending force, and the inner layer net tube effectively moves the inner hollow fiber membrane. Since it can follow, the impact at the time of colliding with an inner layer net cylinder can be made smaller. Moreover, since the outer layer net cylinder has the net yarn extending in the axial direction, it becomes more difficult to be deformed with respect to the bending force, and the entire movement of the hollow fiber membrane can be reduced with the outer layer net cylinder. It is possible to more effectively prevent the hollow fiber membrane from being damaged near the boundary.

  Moreover, it is preferable that at least one end of the outer layer net cylinder and the inner layer net cylinder is embedded in the sealing portion. When the end portion of the outer layer net cylinder is embedded in the sealing portion, the inner layer net cylinder and the hollow fiber membrane can be held inside without the outer layer net cylinder being displaced in the vicinity of the boundary with the sealing portion. It is possible to more effectively prevent the hollow fiber membrane from being damaged near the boundary with the sealing portion. Further, when the end portion of the inner layer net cylinder is embedded in the sealing portion, the inner layer net cylinder can be held inside without being displaced in the vicinity of the boundary with the sealing portion. It is possible to prevent the hollow fiber membrane from being damaged.

  Moreover, it is preferable that the opening ratio of the outer layer net cylinder is 60% or more and 90% or less, and the opening ratio of the inner layer net cylinder is 65% or more and 95% or less. By these opening ratios, the balance between the fluidity of the stock solution and the net rigidity can be improved.

The longitudinal cross-sectional view which shows an example of the hollow fiber membrane module of this invention. It is a figure which shows an example of the principal part of the hollow fiber membrane module of this invention, (a) is a right view of a net cylinder, (b) is a perspective view of an outer layer net cylinder, (c) is a perspective view of an inner layer net cylinder . The right view which shows the other example of the net cylinder of the hollow fiber membrane module of this invention. The top view which shows the other example of the net shape of the net cylinder of the hollow fiber membrane module of this invention. The graph which shows the result of an Example and a comparative example. The longitudinal cross-sectional view which shows an example of the conventional hollow fiber membrane module.

  As shown in FIG. 1, the hollow fiber membrane module of the present invention includes a housing 10 having a stock solution inlet 12 and a permeate outlet 14, a plurality of hollow fiber membranes 1 accommodated in the housing 10, and a hollow fiber thereof. A plurality of inner layer net cylinders 2 for dividing and bundling the membrane 1 into a plurality, a single or a plurality of outer layer net cylinders 3 for bundling a plurality of the inner layer net cylinders 2, and provided at least on one end side of the hollow fiber membrane. It has the sealing part 4 which prevents mixing with a flow path and a permeation | transmission side flow path. In this embodiment, the sealing part 4 is sealed with a sealing part 4a in which one end of the hollow fiber membrane 1 is sealed without being opened by the casting agent, and the other end is sealed with the casting agent in an open state. An example including the sealing part 4b is shown.

  The housing 10 accommodates a plurality of hollow fiber membranes 1 and includes, for example, as shown in FIG. 1, a cylindrical body portion 11 and cap portions 15 and 16 provided at both ends thereof. Further, the cap part 15 is provided with a stock solution inlet 12, the cap part 16 is provided with a permeate outlet 14, and the body part 11 is provided with a concentrated stock solution outlet 13. Any material can be used as the material of the housing 10 as long as no problems such as elution of impurities and particles occur. Examples of the material include a vinyl chloride resin, a polycarbonate resin, and a polysulfone resin.

  Examples of the hollow fiber membrane 1 include microfiltration membranes, ultrafiltration membranes, reverse osmosis membranes, dialysis membranes, and the like, and those having pore diameters, outer diameters, and lengths can be used according to the application and production method. Examples of the material of the hollow fiber membrane 1 include polysulfone, polyethersulfone, vinylidene fluoride, polyacrylonitrile, polyvinyl chloride-polyacrylonitrile copolymer, aromatic polyamide, and cellulose acetate.

  The inner-layer net cylinder 2 divides and bundles the hollow fiber membranes 1 into a plurality, and the number of hollow fiber membranes 1 bundled by one inner-layer net cylinder 2 is preferably 400 to 6000, more preferably 400 to 4000. . A plurality of inner layer net cylinders 2 are bundled by one or a plurality of outer layer net cylinders 3, but the number of inner layer net cylinders 2 bundled by one outer layer net cylinder 3 is preferably 1 to 12, 6 is more preferable. The number of divisions by the entire inner layer net cylinder 2 is preferably 2 to 12 divisions, and more preferably 2 to 6 divisions.

  In the present embodiment, as shown in FIG. 2, an example in which two inner layer net cylinders 2 are bundled by one outer layer net cylinder 3 is shown. In this example, the inner layer net cylinder 2 has a semicircular cross section, but the inner layer net cylinder 2 may be formed in such a shape in advance, and the inner layer net cylinder 2 having a circular cross section is inserted into the outer layer net cylinder 3. It may be deformed.

  Further, in the illustrated example, both ends of the outer layer net cylinder 3 and the inner layer net cylinder 2 are embedded in the sealing portion 4. Moreover, the outer layer net cylinder 3 has the net thread | yarn 3a extended in an axial center direction, and the inner layer net cylinder 2 shows the example which is the shape where the net thread | yarn 2a extended in the direction inclined with respect to the circumferential direction cross | intersects.

  In this example, the outer layer net cylinder 3 has a structure in which a net yarn 3a extending in the axial direction and a net yarn 3b extending in the circumferential direction are fused at the intersection.

  In the present invention, the thickness of the outer layer net cylinder 3 exceeds 1.0 mm, preferably the thickness is 1.1 to 5.0 mm, more preferably 1.5 to 3.5 mm. Further, the net yarn diameter of the outer layer net cylinder 3 is 0.9 mm or more and 5.0 mm or less, preferably 1.0 mm or more and 2.0 mm or less.

  In the present invention, the “net yarn” refers to a linear member constituting a net, and the cross section thereof is not limited to a circle, and may be any polygon such as a triangle or a rectangle, an ellipse or the like. Further, it is preferable that the intersecting net yarns are integrally formed, but the intersecting portion may or may not be fixed. The “net yarn diameter” refers to the maximum length in the cross section of the linear member constituting the net. For example, in the case of an elliptical cross section, the long diameter corresponds to the net yarn diameter.

  The opening ratio of the outer net cylinder 3 is preferably 60 to 90%, and more preferably 80 to 90%. Here, the “aperture ratio” refers to a ratio obtained from the area of a portion where no net yarn is projected in plan view.

  Examples of the material of the outer layer net cylinder 3 include polypropylene, polyethylene, polysulfone, polytetrafluoroethylene, polyvinyl chloride, polyvinylidene fluoride, polyphenylene sulfide polyphenylene ether, polycarbonate, and nylon.

  In the present invention, the inner layer net cylinder 2 has a thickness of 1.0 mm or less, preferably a thickness of 0.2 to 0.9 mm, and more preferably a thickness of 0.3 to 0.8 mm. Moreover, the net yarn diameter of the inner layer net cylinder 2 is 0.1 mm or more and 1.0 mm or less, preferably 0.2 mm or more and 0.6 mm or less. The opening ratio of the inner net cylinder 2 is preferably 65 to 95%, and more preferably 85 to 95%.

  Examples of the material of the inner layer net cylinder 2 include polypropylene, polyethylene, polysulfone, polytetrafluoroethylene, polyvinyl chloride, polyvinylidene fluoride, polyphenylene sulfide polyphenylene ether, polycarbonate, and nylon.

  The sealing part 4a and the sealing part 4b are sealed with a casting agent such as a casting resin. As the casting resin, any material can be used as long as the hollow fiber membrane bundle 1 can be sealed. From the viewpoint of reliably sealing one end of the hollow fiber membrane bundle 1, in particular, at least urethane resin and epoxy resin are used. It is preferable to use one as a main component.

(Other embodiments)
(1) In the above-described embodiment, an example in which two inner-layer net cylinders 2 are bundled by one outer-layer net cylinder 3 has been shown. However, in the present invention, as shown in FIG. Can be taken. The longitudinal cross-sectional shape of the inner layer net cylinder 2 may be any of a semicircle, a fan shape, and a rounded shape.

  For example, as shown in FIG. 3A, two outer layer net cylinders 3 are bundled by two outer layer net cylinders 3, respectively, and as shown in FIG. As shown in FIG. 3 (c), two inner layer net cylinders 2 are respectively bundled by four outer layer net cylinders 3, etc. Good.

  (2) In the above-described embodiment, the sealing portion 4 includes the sealing portion 4a in which one end of the hollow fiber membrane 1 is sealed without being opened by the casting agent, and the other end is opened by the casting agent in the opened state. In the present invention, the U-shaped hollow fiber membrane 1 is used, so that the sealed portion 4a sealed without opening is not necessary. It may be a structure.

  Moreover, the both ends of the hollow fiber membrane 1 are made into the sealing part 4b sealed by the casting agent in the open state instead of the sealing part 4a sealed without opening, and both ends of the hollow fiber membrane 1 are You may provide the sealing part 4 sealed by the casting agent in the open state.

  In that case, on both sides in the housing 10, the sealing portions 4 on both sides are held watertight, the cap portion 15 is formed in a closed space, and a stock solution inlet 12 is provided in the body portion 11. The hollow fiber membrane module shown in FIG.

  Moreover, it is also possible to constitute an internal pressure type hollow fiber membrane module by performing membrane separation by flowing the stock solution into the hollow fiber membrane 1 from the stock solution inlet 12 of the cap portion 15. In that case, the outlet of the concentrate becomes the outlet of the permeate.

  (3) In the above-described embodiment, an example of a structure in which both ends of the outer layer net tube 3 and the inner layer net tube 2 are embedded in the sealing portion 4 is shown. However, in the present invention, the outer layer net tube 3 and the inner layer net tube 2 may be a structure in which only one of the two is embedded in the sealing portion 4. Further, a structure in which only one end of the outer layer net cylinder 3 and the inner layer net cylinder 2 is embedded in the sealing portion 4 may be employed.

  (4) In the above-described embodiment, the outer layer net tube 3 has the net yarn 3a extending in the axial direction, and the inner layer net tube 2 has a shape in which the net yarn 2a extending in the direction inclined with respect to the circumferential direction intersects. However, as shown in FIG. 4, in the present invention, the net tube can take various forms. Examples of the opening shape of the net cylinder include a triangle, a quadrangle (rhombus, square, rectangle, parallelogram, etc.), a hexagon, and the like.

  For example, the structure shown in FIG. 4A is a structure in which a net yarn 3a in which the outer net cylinder 3 extends in the axial direction and a net yarn 3c that extends in a direction inclined with respect to the circumferential direction are fused at the intersection. Have The inner-layer net cylinder 2 has a structure in which a net yarn 2a extending intersecting in a direction inclined with respect to the circumferential direction and a net yarn 2bc extending in the circumferential direction are fused at the intersection.

  4 (b) shows a structure in which a net yarn 3a in which the outer layer net cylinder 3 extends in the axial direction and a net yarn 3c that zigzags in a direction inclined with respect to the circumferential direction are fused at the intersection. Have The inner layer net cylinder 2 has a structure in which net yarns 2a extending in a direction inclined with respect to the circumferential direction are fused at an intersection.

  As shown in FIG. 4C, the net yarn 3a in which the outer layer net cylinder 3 extends in the axial direction and the net yarn 3c extending in a direction inclined with respect to the circumferential direction are fused at the intersection. It has a structure. The inner layer net cylinder 2 has a structure in which two types of net yarns 2c extending in the circumferential direction are fused at an intersection to form a hexagonal opening.

  Examples and the like specifically showing the present invention will be described below.

Example 1
As shown in FIG. 3 (a), two semi-cylindrical outer layer net cylinders were prepared, and the inner layer net cylinder was prepared so that it was divided into two parts and divided into four parts as a whole. The outer layer cylinder is made of polypropylene and has a shape of FIG. 2B, a thickness of 2.5 mm, a net yarn diameter of 1.5 mm in the axial direction, a net yarn diameter of 1.1 to 1.6 mm in the circumferential direction, and an aperture ratio of 84. The inner layer net cylinder was made of polypropylene, the shape was FIG. 2 (c), the thickness was 0.7mm, the net yarn diameter inclined in the axial direction was 0.28 to 0.40mm, and the aperture ratio was 91%. .

  A total of 10800 polysulfone-based hollow fiber membranes having an outer diameter of 1.2 mm are divided into four parts, bundled with an inner layer net cylinder, inserted into the outer layer net cylinder, and a casting agent (epoxy resin) together with both net cylinders ), The other end was sealed without being opened, and the other end was sealed, and then housed in a cylindrical housing having a length of 1284 mm and an inner diameter of 160 mmφ.

For the obtained hollow fiber membrane module, water was passed only at the stock solution outlet port installed on the side of the housing at a flow rate of 6 m ³ / hr, repeated operation of water flow / stop was performed, and the hollow fiber membrane was broken. The occurrence of was evaluated. The result is shown in FIG.

Comparative Example 1
In Example 1, a hollow fiber membrane module was produced in exactly the same manner as in Example 1, except that the same number of hollow fiber membranes were divided into two and bundled by outer layer net cylinders without providing the inner layer net cylinders. Later, it was evaluated. The result is shown in FIG.

As is clear from the results shown in FIG. 5, the hollow fiber membrane was confirmed to be broken at 12,000 times in the module of Comparative Example 1, whereas the hollow fiber was confirmed at 28,000 times in the module of Example 1. The film was not broken. From this, it was found that the durability against breakage of the hollow fiber membrane is doubled or more by the present invention.
Comparative Example 2
In Example 1, a hollow fiber membrane module was produced and evaluated in the same manner as in Example 1 except that the same net as the outer layer net cylinder was used to produce the inner layer net cylinder and the outer layer net cylinder. As a result, it was confirmed that the hollow fiber membrane was broken 1000 times. When the broken part was confirmed, it was found that the hollow fiber membrane was damaged mainly due to the collision between the inner layer net tube and the hollow fiber membrane, and the main cause was the fracture.

Comparative Example 3
A hollow fiber membrane module was produced in the same manner as in Example 1 except that the inner layer net cylinder and the outer layer net cylinder were produced using the same net as the inner layer net cylinder in Example 1, and then evaluated. As a result, breakage of the hollow fiber membrane was confirmed after 3000 times. When confirming the ruptured part, it is likely that the fiber rupture due to the tensile force due to the weight of the hollow fiber membrane and the vibration of the bundle of hollow fiber membranes during water flow is the main cause near the boundary between the hollow fiber membrane and the sealing part. I understood.

DESCRIPTION OF SYMBOLS 1 Hollow fiber membrane 2 Inner layer net cylinder 3 Outer layer net cylinder 4 Sealing part 10 Housing 11 Stock solution inlet 12 Permeate outlet

Claims (5)

A housing having a stock solution inlet and a permeate outlet, a plurality of hollow fiber membranes accommodated in the housing, a plurality of inner layer net tubes that divide and bundle the hollow fiber membranes, and a plurality of inner layer net tubes In a hollow fiber membrane module having one or a plurality of outer layer net cylinders for bundling, and a sealing portion that is provided at least on one end side of the hollow fiber membrane and prevents mixing of the stock solution side channel and the permeate side channel,
The outer layer net cylinder has a thickness exceeding 1.0 mm, the net yarn diameter is 0.9 mm or more and 5.0 mm or less,
The inner layer net cylinder has a thickness of 1.0 mm or less, and a net yarn diameter of 0.1 mm or more and 1.0 mm or less.   The hollow fiber according to claim 1, wherein one end of the hollow fiber membrane is sealed without being opened by a casting agent, and the other end is sealed by the casting agent in an opened state. Membrane module.   The hollow according to claim 1 or 2, wherein the outer layer net tube has a net yarn extending in an axial direction, and the inner layer net tube has a shape in which net yarns extending in a direction inclined with respect to a circumferential direction intersect. Yarn membrane module.   The hollow fiber membrane module according to any one of claims 1 to 3, wherein at least one end of the outer layer net tube and the inner layer net tube is embedded in the sealing portion. The hollow fiber membrane module according to any one of claims 1 to 3, wherein an opening ratio of the outer layer net cylinder is 60% or more and 90% or less, and an opening ratio of the inner layer net cylinder is 65% or more and 95% or less.

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