JP4740194B2 - Hollow fiber membrane module - Google Patents

Description

  The present invention relates to a hollow fiber membrane module used for water treatment.

  In general, the hollow fiber membrane module is generally composed of a casing having a fluid inlet / outlet, a cap, a hollow fiber membrane bundle, a net for protecting the bundle, and a fixed portion in which an end of the hollow fiber membrane bundle is sealed with a resin. When a filtration operation is performed using such a membrane module, the processing stock solution and the permeated water flow in or out from the inlet / outlet of the casing.

When the processing stock solution or permeate flows in or out from the inlet / outlet of the casing, the hollow fiber membrane in the vicinity of the inlet / outlet may vigorously oscillate due to the liquid flow. In such a case, even if the hollow fiber membrane bundle is protected by the protective net, the hollow fiber membrane may be damaged.
JP-A-8-206468 JP 2004-89799 A

  Patent Document 1 discloses a technique for suppressing damage to the hollow fiber membrane by disposing a flat liquid contact plate in the vicinity of the liquid inlet / outlet and relaxing the hydraulic pressure on the hollow fiber membrane bundle. However, with a flat plate only, if the diameter of the liquid inlet / outlet is large, there is a problem that the space (dead volume) formed by the hit plate increases and the filling rate of the hollow fiber membrane decreases.

  Patent Document 2 discloses a technique for relieving fluid pressure due to entering and exiting a fluid from a fluid inlet / outlet by using a reinforcing material for a hollow fiber membrane bundle having a curved buffer plate integrated with an outer frame. In this case, since the outer frame and the buffer plate are integrated, there is a problem in terms of freedom of attachment. In addition, when the buffer plate is curved, the buffer plate and the membrane bundle are in contact with each other, so the above-described dead volume is almost eliminated, but when the hydraulic pressure is high, the hollow fiber membrane in contact with the buffer plate May be damaged.

  The present invention provides a hollow fiber membrane module capable of suppressing damage to a hollow fiber membrane in the vicinity of a liquid inlet / outlet during filtration operation, suppressing dead volume, and increasing the filling rate of the hollow fiber membrane. Is an issue.

The invention of claim 1 is a solution to the problem.
A hollow fiber membrane module in which a plurality of bundles of hollow fiber membranes covered with a protective net are housed in a cylindrical case having a liquid inlet / outlet on the side surface and closed at both ends,
The plurality of hollow fiber membrane bundles is a combination of two semicircular planar shapes or three or more combinations of planar fan shapes,
The plurality of hollow fiber membrane bundles are arranged such that each curved surface faces the inner wall surface of the cylindrical case, and each flat surface faces a plane of another hollow fiber membrane bundle adjacent in the circumferential direction. ,
A protective plate made of a flat plate and a curved plate is disposed inside the protective net of the hollow fiber membrane bundle at a position facing the liquid inlet / outlet,
A hollow fiber membrane module is provided in which the protective plate has a curved plate on at least one side of the flat plate.

  By using a protective plate having a flat surface and a curved surface as described above, the specific operational effects 1 to 3 can be obtained as described below.

  Action effect 1: When a protective plate having a flat surface and a curved surface is used, the dead volume can be reduced as compared with the case where a protective plate having only a flat surface is used, so that the filling rate of the hollow fiber membrane can be increased.

  Effect 2: When a protective plate having a flat surface and a curved surface is used, a small dead volume exists between the flat surface portion and the membrane bundle, so that even when a large hydraulic pressure is applied, the hollow fiber membrane can be Compared with the case where a protective plate having only a curved surface is used, the possibility of damaging the hollow fiber membrane is significantly reduced.

  Effect 3: When a protective plate having a flat surface and a curved surface is used, when the liquid flows out from the liquid inlet / outlet and the flow rate is large, even if the protective plate is pressed in the direction of the liquid inlet / outlet, Since there is a dead volume between them, there is no possibility that the liquid flow is hindered. On the other hand, in the case of a protection plate having only a curved surface, there is no dead volume between the protection net and the liquid flow may be hindered.

  In the present invention, in order to obtain the above-described operational effects 1 to 3, the width of the plane of the protective plate is preferably in the range of 50 to 80% of the diameter of the liquid inlet / outlet.

The invention of claim 2 is another means for solving the problems.
The plurality of hollow fiber membrane bundles are arranged so that the portions where the planes of the hollow fiber membrane bundles adjacent to each other in the circumferential direction are directly opposed to the liquid inlet / outlet port,
One protective plate is disposed in each protective net of the two adjacent hollow fiber membrane bundles,
The hollow fiber membrane module according to claim 1, wherein the protective plate has a curved plate only on one side of the flat plate, and the flat plate is disposed so as to face the liquid inlet / outlet. .

  When the number of hollow fiber membrane bundles is two or more and the portions where the planes of the hollow fiber membrane bundles adjacent to each other in the circumferential direction face each other are arranged so as to face the liquid inlet / outlet, they are adjacent to each other. By arranging one predetermined protective plate in each of the protective nets of the two film bundles, the effects 1 to 3 of the present invention can be obtained.

The invention of claim 3 is another solution to the problem.
The plurality of hollow fiber membrane bundles are arranged so that an arc portion of one hollow fiber membrane bundle faces the liquid inlet / outlet,
One protective plate is arranged in the protective net of the one hollow fiber membrane bundle,
The hollow fiber membrane module according to claim 1, wherein the protective plate has curved plates on both sides of the flat plate, and the flat plate is disposed so as to face the liquid inlet / outlet.

  When the number of hollow fiber membrane bundles is two or more, and when the arc portion of one hollow fiber membrane bundle is arranged so as to face the liquid inlet / outlet, one sheet is provided in the protective net of one membrane bundle. By arranging the predetermined protective plate, the effects 1 to 3 of the present invention can be obtained.

The invention of claim 4 is another means for solving the problems,
A hollow fiber membrane module in which a bundle of hollow fiber membranes covered with a protective net is accommodated in a cylindrical case having a liquid inlet / outlet on its side and closed at both ends,
A protective plate made of a flat plate and a curved plate is disposed inside the protective net of the hollow fiber membrane bundle at a position facing the liquid inlet / outlet,
Provided is a hollow fiber membrane module in which the protective plate has curved plates on both sides of the flat plate, and the flat plate is arranged so as to face the liquid inlet / outlet.

  When the hollow fiber membrane bundle is one bundle, the operation effects 1 to 3 of the present invention can be obtained by arranging one predetermined protective plate in the protective net.

  The protective plate used in the present invention preferably has a plurality of holes having the same or different diameters. When such holes are provided, the liquid enters and exits from the holes, so that the filtration efficiency (the amount of filtration per unit time) can be increased.

  The present invention is particularly suitable when the diameter of the liquid inlet / outlet formed in the cylindrical case is 140 mm or more.

  The hollow fiber membrane module of the present invention can continue the stable filtration operation with almost no damage to the hollow fiber membrane due to the filtration operation.

(1) Hollow fiber membrane module of FIGS. 1 to 3 An embodiment of the present invention will be described with reference to FIGS. FIG. 1 (A) is a front view including a partial cross-sectional view in the longitudinal direction of the hollow fiber membrane module 10 of the present invention, and FIG. 1 (B) is a cross-sectional view of a portion including the liquid inlet / outlet of FIG. 1 (A). 2 is a partially enlarged view of FIG. 1B, and FIG. 3 is a perspective view of a protective plate. In FIG. 2, the display of the hollow fiber membrane is partially omitted.

  As shown in FIGS. 1A and 1B, the cylindrical case 11 is closed at both ends with caps 12a and 12b each having an inlet / outlet connected to a pipe, and is substantially at the center in the height direction of the side surface. The part has a liquid inlet / outlet 13.

  The height of the cylindrical case 11 excluding the caps 12a and 12b is 1066 mm, the outer diameter is 310 mm, and the diameter of the liquid inlet / outlet 13 is 140 mm.

  In the cylindrical case 11, a total of four bundles of hollow fiber membrane bundles 16 to 19 that are covered with a protective net 15 are accommodated. The number of hollow fiber membrane bundles is not particularly limited, but can be about 2 to 8 bundles. A hollow fiber membrane having a known size and material can be used.

  The hollow fiber membrane bundles 16 to 19 are sealed at the upper end side with the resin 14 and are fixed to the inner wall surface of the cylindrical case 11, and the lower end side is also fixed in the same manner. The protective net 15 may be single or double or more.

  Each of the hollow fiber membrane bundles 16 to 19 has a fan shape in which a circle is divided into four equal parts, each curved surface faces the inner wall surface of the cylindrical case 11, and each two flat surfaces (side surfaces) are They are arranged so as to face the plane (side surface) of another hollow fiber membrane bundle adjacent in the circumferential direction. For example, two planes (side surfaces) of the film bundle 16 are opposed to one plane (side surface) of the film bundle 17 and one plane (side surface) of the film bundle 19.

  As shown in FIG. 2, the four hollow fiber membrane bundles 16 to 19 are such that the portion where the flat surface 16 a of the hollow fiber membrane bundle 16 and the flat surface 17 b of the hollow fiber membrane bundle 17 adjacent in the circumferential direction are facing each other is liquid. It is arranged so as to face the entrance / exit 13.

  The hollow fiber membranes are protected from the liquid pressure associated with the entry and exit of the liquid on the inner side of the protective net 15 of the hollow fiber membrane bundle 16 and the inner side of the protective net 15 of the hollow fiber membrane bundle 17 at the position facing the liquid inlet / outlet 13, respectively. A protective plate 20 is arranged for this purpose. When the protection nets 15 are multiple, the protection plate 20 is disposed inside the outermost protection net 15 (for example, between two and three layers in the case of a triple net).

  As shown in FIG. 3, the protective plate 20 includes a flat plate 21 and a curved plate 22 integrated with one side thereof. The size of the protection plate 20 is equal to or larger than the opening area of the liquid inlet / outlet 13.

  As shown in FIG. 1 (B), the protection plate 20 has an upper end side 20a fixed to the inner wall surface of the cylindrical case 11 with the resin 14 together with the hollow fiber membrane bundles 16-19. Further, in order to increase the fixing strength of the protective plate 20, the lower end side (not shown) can be similarly fixed.

  The protective plate 20 on the hollow fiber membrane bundle 16 side has a side 21 a of the flat plate 21 close to the protective net 15 on the flat (side) side of the membrane bundle 16 (the flat plate 21 faces the liquid inlet / outlet 13. ), The curved plate 22 is disposed so as to be close to the protective net 15 on the curved surface side of the film bundle 16. It is preferable that there is an interval between the flat plate 21, the curved plate 22, and the protective net 15 so that the liquid can flow. Thus, since the protective plate 20 has the flat plate 21 and the curved plate 22, the dead plate between the flat plate 21 and the protective net 15 is compared with a protective plate made only of a flat plate of the same size. The volume 30 can be reduced.

  The protective plate 20 is formed in a state where a total of six large-diameter holes 23 are vertically separated across the flat plate 21 and the curved plate 22, and at the intermediate position, five pieces are bent on the flat plate 21 side. Five small-diameter holes 24 are formed on the face plate side.

  The large-diameter hole 23 and the small-diameter hole 24 are both for allowing the liquid to flow through the protective plate 20, and thus the formation position, size, number, and the like are not particularly limited. The large diameter hole can be about 40-50 mm in diameter, and the small diameter hole can be about 10-20 mm in diameter.

  The protective plate 20 has a small diameter hole 24 at a position facing the liquid inlet / outlet 13, and the large diameter hole 23 does not face the liquid inlet / outlet 13.

As shown in FIG. 3, an upper protrusion group 25 and a lower protrusion group 26 are formed on the surface of the flat plate 21 on the side 21 a side. The dead space 30 is maintained by attaching the protection plate 20 so that the upper protrusion group 25 and the lower protrusion group 26 are on the protective net 15 side.

In order to obtain the operational effects 1 to 3 of the present invention, the relationship between the two protective plates 20 and the diameter (D) of the liquid inlet / outlet 13 is given by the following formula when the width of the flat plate 21 of the protective plate 20 is W: It is preferable that D / 2W = 50 to 80% (preferably 65 to 75%) is satisfied.

  The material in particular of the cylindrical case 11 and the protection board 20 is not restrict | limited, For example, the various synthetic resins described in patent document 1 can be mentioned.

  Next, an operation method of the hollow fiber membrane module 10 will be described. A case where the processing stock solution is supplied from the caps 12a and 12b and the permeate is discharged from the liquid inlet / outlet 13 will be described.

  The stock solutions sent from the caps (processing stock solution supply ports) 12 a and 12 b enter the hollow fiber membranes in the hollow fiber membrane bundles 16 to 19 opened at the end face of the resin 14 and are filtered. The permeate that has permeated through the membrane surface moves toward the liquid inlet / outlet 13, and passes through the holes 16 (large diameter hole 23 and small diameter hole 24) between the flat surface 16 a and the flat surface 17 b and the protective plate 20. It flows in the direction and is discharged from the liquid inlet / outlet 13. At this time, the hollow fiber membrane is pushed toward the liquid inlet / outlet by the hydraulic pressure, but is not pushed and bent toward the liquid inlet / outlet.

  Moreover, at the time of back pressure washing | cleaning, although washing | cleaning liquid is introduce | transduced into the cylindrical case 11 from the liquid inlet / outlet 13, since the protection board 20 exists, damage to a hollow fiber membrane is prevented.

  Since the hollow fiber membrane module 10 of the present invention exerts the effects 1 to 3 by the action of the protective plate 20, it can maintain stable filtration performance for a long period of time.

(2) Hollow Fiber Type Membrane Module in FIGS. 4 and 5 FIG. 4 is the same membrane module as in FIG. 2, in which the arc portion of the membrane bundle 17 faces the liquid inlet / outlet 13. In FIG. 4, the display of the hollow fiber membrane is partially omitted.

  The protective plate 120 has curved plates 122 a and 122 b on both sides of the flat plate 121, and is arranged in the protective net 15 so that the flat plate 121 faces the liquid inlet / outlet 13. A small dead volume 130 exists between the flat plate 121 and the protective net 15.

  The protective plate 120 has a shape in which the curved plate 22 is attached to the side 21a side of the flat plate 21 in the protective plate 20 shown in FIG. Holes corresponding to the large-diameter hole 23 and the small-diameter hole 24 of the protective plate 20 and the protrusion groups corresponding to the upper protrusion group 25 and the lower protrusion group 26 can be appropriately formed for the purpose of obtaining the same action.

  FIG. 5 is a cross-sectional view in the width direction of a membrane module having one hollow fiber membrane bundle. In FIG. 5, the indication of the hollow fiber membrane is omitted.

  The protection plate 120 is the same as that in FIG. 4, and is disposed in the protection net 15 so that the flat plate 121 faces the liquid inlet / outlet 13. A small dead volume 130 exists between the flat plate 121 and the protective net 15.

  4 and 5, the relationship between the width (W) of the flat plate 121 of the protective plate 120 and the diameter (D) of the liquid inlet / outlet port 13 is expressed by the following formula: D / W = 50 to 80% (preferably 65 to 75). %) Is preferable.

  The membrane module shown in FIGS. 4 and 5 can obtain the effects 1 to 3 of the present invention in the same manner as the membrane module shown in FIGS.

Example 1
Using the two protective plates shown in FIG. 3, the hollow fiber membrane module shown in FIGS. 1 and 2 was produced (D / 2W = 71%). A hollow fiber membrane made of cellulose acetate resin (FUC-1583, manufactured by Daicel Chemical Industries, Ltd.) was used, and one hollow fiber membrane bundle was filled with 5580 (four in total, 22320). Both ends of the hollow fiber membrane, the protective net, and the protective plate were fixed with a urethane resin adhesive.

A durability test was conducted using the produced hollow fiber membrane module. In the test method, water was passed through caps 12a and 12b inside hollow fiber membranes of hollow fiber membrane bundles 16 to 19 at 10 m ³ / hr for 26 seconds and then in the opposite direction at 40 m ³ / hr for 6 seconds. This was repeated with one operation of back pressure washing. The hollow fiber membranes were taken out of the hollow fiber membrane bundles 16 and 17 when repeated 50,000 times and observed with the naked eye, but no damage was found.

Comparative Example 1
A hollow fiber membrane module was produced in the same manner except that two protective plates having only a curved surface having the same area were used instead of the protective plate 20 in FIGS.

  Using this hollow fiber membrane module, the same durability test as in Example 1 was performed. As a result, when the hollow fiber membrane bundles 16 and 17 were removed 10,000 times and observed with the naked eye, the average of 25 hollow fiber membranes was found in both the hollow fiber membrane bundles 16 and 17. It was damaged (partial disconnection, etc.).

(A) is a front view including the fragmentary sectional view of the vertical direction of the hollow fiber type membrane module of this invention, (b) is sectional drawing of the width direction of (a). The elements on larger scale of FIG.1 (b). Sectional drawing of the form from which the accommodation state of a film bundle differs from FIG.1 (b). The perspective view of a protection board. Sectional drawing of the width direction of the hollow fiber type membrane module which is another embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Hollow fiber type membrane module 11 Cylindrical case 13 Liquid inlet / outlet 15 Protective net 16-19 Hollow fiber membrane bundle 20 Protective plate 21 Flat plate 22 Curved surface plate

Claims (6)

A hollow fiber membrane module in which a plurality of bundles of hollow fiber membranes covered with a protective net are housed in a cylindrical case having a liquid inlet / outlet on the side surface and closed at both ends,
The plurality of hollow fiber membrane bundles is a combination of two semicircular planar shapes or three or more combinations of planar fan shapes,
The plurality of hollow fiber membrane bundles are arranged such that each curved surface faces the inner wall surface of the cylindrical case, and each flat surface faces a plane of another hollow fiber membrane bundle adjacent in the circumferential direction. ,
A protective plate made of a flat plate and a curved plate is disposed inside the protective net of the hollow fiber membrane bundle at a position facing the liquid inlet / outlet,
A hollow fiber membrane module, wherein the protective plate has a curved plate on at least one side of the flat plate. The plurality of hollow fiber membrane bundles are arranged so that the portions where the planes of the hollow fiber membrane bundles adjacent to each other in the circumferential direction are directly opposed to the liquid inlet / outlet port,
One protective plate is disposed in each protective net of the two adjacent hollow fiber membrane bundles,
The hollow fiber membrane module according to claim 1, wherein the protective plate has a curved plate only on one side of the flat plate, and the flat plate is disposed so as to face the liquid inlet / outlet. The plurality of hollow fiber membrane bundles are arranged so that an arc portion of one hollow fiber membrane bundle faces the liquid inlet / outlet,
One protective plate is arranged in the protective net of the one hollow fiber membrane bundle,
The hollow fiber membrane module according to claim 1, wherein the protective plate has curved plates on both sides of the flat plate, and the flat plate is disposed so as to face the liquid inlet / outlet. A hollow fiber membrane module in which a bundle of hollow fiber membranes covered with a protective net is accommodated in a cylindrical case having a liquid inlet / outlet on its side and closed at both ends,
A protective plate made of a flat plate and a curved plate is disposed inside the protective net of the hollow fiber membrane bundle at a position facing the liquid inlet / outlet,
The hollow fiber membrane module, wherein the protective plate has curved plates on both sides of the flat plate, and the flat plate is disposed so as to face the liquid inlet / outlet.   The hollow fiber membrane module according to any one of claims 1 to 4, wherein the protective plate has a plurality of holes having the same or different diameters. The hollow fiber membrane module according to any one of claims 1 to 5, wherein a diameter of the liquid inlet / outlet is 140 mm or more.

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