JP6834532B2 - Hollow fiber membrane module repair method and hollow fiber membrane module - Google Patents

Description

The present invention relates to a method for repairing a hollow fiber membrane module and a hollow fiber membrane module repaired by the method of the present invention.

Hollow fiber membrane modules having a plurality of hollow fiber membranes and a water collecting portion are widely used for water treatment such as sewage / purification treatment and purification of reclaimed water. When various water treatments are performed using this, foreign substances and the like contained in the water to be treated are blocked on the surface of the hollow fiber membrane, so that the cleaning using air scrubbing and the liquid passing in the direction opposite to the filtration direction are performed. Cleaning, cleaning with chemicals, etc. are carried out regularly.

By the way, when these washings are repeated for a long period of time, the surface of the hollow fiber membrane deteriorates in physical and / or chemical durability. Damaged portions may occur on the surface of the hollow fiber membrane having deteriorated durability, and fine particles in the water to be treated are mixed into the filtered water side from there.
Therefore, in order to maintain the separation / filtration performance of the hollow fiber membrane module, if there is a damaged part, repair it. As a repair method, for example, a method of directly applying a resin to a damaged portion and curing (Patent Document 1), a method of applying a resin to an open end of a damaged hollow fiber membrane (Patent Document 2), and a hollow fiber. A method of injecting resin into the hollow portion of the membrane to cure it (Patent Document 3), and a method of excising the damaged hollow fiber membrane and applying the resin so as to cover the end opened by the excision (Patent Document 4). ), There is a method of cutting the broken hollow fiber membrane and ligating the cut thread.

Japanese Patent No. 5637214 International Publication No. 2006/037234 Japanese Patent No. 581738 International Publication No. 2012/147932

In the repair methods disclosed in Patent Document 1 and Patent Document 3, when the number of damaged parts generated per hollow fiber membrane is large, resin must be applied or injected one by one to all the damaged parts. It must be inferior in workability.
Further, the repair method disclosed in Patent Document 2 cannot be applied in the first place unless it is a hollow fiber membrane module having a structure capable of sealing the open end portion of the damaged hollow fiber membrane. In order to design a hollow fiber membrane module so that the open end can be sealed, the shape of the hollow fiber membrane module becomes complicated. Therefore, the repair method of Patent Document 2 is actually applied to the hollow fiber membrane module. Has restrictions on its shape and structure.
Further, in the repair method disclosed in Patent Document 4, when the hollow fiber membrane module after repair is subjected to air scrubbing cleaning, the resin applied to the tip of the hollow fiber membrane and cured is harder than the hollow fiber membrane. Such resin rubbed against the adjacent hollow fiber membrane, causing the recurrence of damage to the hollow fiber membrane. Further, since the surface area of the hollow fiber membrane repaired by the method of Patent Document 4 is increased by the amount of the applied resin, when air scrubbing cleaning is performed, the portion fixed to the water collecting portion of the hollow fiber membrane module It was easily bent, and the repaired hollow fiber membrane was the cause of the recurrence of the breakage.

The present invention has been made in view of the above background, and is a method for repairing a hollow fiber membrane module which is excellent in workability and has no limitation on the applicable hollow fiber membrane module, and the hollow fiber repaired by the repair method. Provided are a method for repairing a hollow fiber membrane module and a hollow fiber membrane module repaired by the repair method, in which the repaired hollow fiber membrane and the adjacent hollow fiber membrane are not easily damaged even if the membrane module is subjected to air scrubbing cleaning. To do.

The present invention has the following aspects.
That is, the present invention relates to the following.
[1] A method for repairing a hollow fiber membrane module including a plurality of hollow fiber membranes and a potting resin for fixing the hollow fiber membrane, the hollow fiber membrane including a damaged portion generated in the hollow fiber membrane. A part of the filament membrane in the length direction is excised, and a resin injection nozzle is inserted from the end of the hollow fiber membrane opened by excision, and the viscosity before curing is 10 mPa · s or more and 6,000 mPa · s at room temperature. A method for repairing a hollow fiber membrane module, in which the following repair resin is injected from the resin injection nozzle to cure the repair resin in a state where the repair resin closes a hollow portion of the hollow fiber membrane. ..
[2] The method for repairing a hollow fiber membrane module according to [1], wherein the resin injection nozzle is inserted until the tip of the resin injection nozzle reaches at least the potting resin.
[3] The repair resin having a viscosity before curing of 10 mPa · s or more and 50 mPa · s or less at room temperature is injected into the hollow portion of the hollow fiber membrane from the resin injection nozzle to repair the hollow fiber membrane. The method for repairing a hollow fiber membrane module according to [1] or [2], wherein the repair resin is injected again after impregnating the resin for use.
[4] The hollow fiber is provided with a plurality of hollow fiber membranes and a potting resin for fixing the hollow fiber membrane, and at least one part of the hollow fiber membrane in the length direction is cut off and opened by cutting. The hollow fiber membrane module is a hollow fiber membrane module in which the hollow part of the membrane is closed with a repair resin.
Of the hollow portion, at least a part of the portion where the outer circumference of the hollow fiber membrane is in contact with the potting resin is closed with the repair resin.
A hollow fiber membrane module in which the length of a portion of the hollow portion in which the outer periphery of the hollow fiber membrane is not in contact with the potting resin and which is closed by the repair resin is 30 mm or less.

The method for repairing a hollow fiber membrane module of the present invention is excellent in workability and can be applied to hollow fiber membrane modules having various shapes and structures. Further, even if the hollow fiber membrane joule repaired by the repair method is subjected to air scrubbing cleaning, the repaired hollow fiber membrane and the adjacent hollow fiber membrane are less likely to be damaged.

It is a perspective view which shows an example of the hollow fiber membrane module of this invention. FIG. 2A is an enlarged view of the portion (I) in FIG. 1, and FIG. 2B is an enlarged view of the portion (II) in FIG. It is a figure explaining the repair method of this invention. 4 (a) and 4 (b) are cross-sectional views illustrating the repair method of the present invention, and FIG. 4 (c) is a cross-sectional view illustrating the repaired portion repaired by the repair method of the present invention. It is sectional drawing explaining the more preferable repair method of this invention. It is sectional drawing of the repair part repaired by the repair method permitted by this invention. It is a perspective view which shows another example of the hollow fiber membrane module of this invention. FIG. 8 (a) is an enlarged view of the portion (III) in FIG. 7, and FIG. 8 (b) is an enlarged view of the portion (IV) in FIG.

Hereinafter, the present invention will be described in detail with reference to the drawings, but the present invention is not construed as being limited to these embodiments.
FIG. 1 is a perspective view showing an example of the hollow fiber membrane module of the present invention. The hollow fiber membrane module 10A includes a plurality of hollow fiber membranes 11 arranged in a sheet shape, and two water collecting portions 20a and 20b provided at both ends of the hollow fiber membrane 11 in the length direction. ing. Both ends of each hollow fiber membrane 11 are adhesively fixed to the water collecting portions 20a and 20b by the potting resins 21a and 21b. Further, both ends of the hollow fiber membrane 11 are open and communicate with the water flow channels 22a and 22b provided inside the water collecting portions 20a and 20b.

Further, the hollow fiber membrane module 10A of this example includes two water pipes 30a and 30b that communicate with the two water collecting portions 20a and 20b, and is provided with one of the water collecting portions (upper water collecting portion) 20a. An intake port 24 for obtaining filtered water is formed at the end in the length direction. Therefore, when the water to be treated is suction-filtered by the hollow fiber membrane module 10A, the filtered water collected in the other water collecting portion (lower water collecting portion) 20b passes through the water guide pipes 30a and 30b and collects in the upper side. It is collected in the water part 20a, and the filtered water collected in the upper water collecting part 20a and the lower water collecting part 20b can be taken out from the water intake port 24.

The material of the hollow fiber membrane 11 is not particularly limited. Specific examples include polyolefins such as polyethylene and polypropylene, fluororesins such as polyvinylidene fluoride (PVDF) and polytetrafluoroethylene, polysulfone resins, polyacrylonitrile, cellulose derivatives, polyamides, polyesters, polymethacrylates, and polyacrylates. Can also be mentioned. A resin containing one or more of these can be used. Further, a copolymer of these resins or one in which a substituent is partially introduced may be used.

The potting resins 21a and 21b are not particularly limited as long as they are separated from the filtered water side and the water to be treated side, and may be known. Examples of the material of the potting resins 21a and 21b include thermosetting resins such as polyurethane resin and epoxy resin, and a resin containing at least one of these can be used.

The water collecting portions 20a and 20b and the water pipes 30a and 30b are not particularly limited as long as they are separated from the filtered water side and the water to be treated side, and may be known. As the materials of the water collecting portions 20a and 20b and the headrace pipes 30a and 30b, those having mechanical strength and durability are preferably used, for example, polycarbonate, polysulfone, polyolefin, PVC (polyvinyl chloride), acrylic resin, ABS. Examples thereof include resins, epoxy resins, and modified PPE (polyphenylene ether), and resins containing one or more of these can be used. Alternatively, a corrosion resistant metal such as stainless steel or titanium may be used.

To identify the damaged portion generated in such a hollow fiber membrane module, for example, a leak inspection method capable of identifying the damaged portion, for example, a gas is sent into the membrane immersed in a liquid such as water or a surfactant to generate bubbles. It is performed by a method of identifying a damaged part depending on the situation, or a method of pouring a coloring fluid such as a coloring liquid and identifying the damaged part by the presence or absence of coloring.

The method for repairing the hollow fiber membrane module of the present invention (hereinafter, also referred to as “the present method”) is performed as shown in FIGS. 3 and 4, for example.
First, as shown in FIG. 3, a part in the length direction including the broken portion 12 is cut off from the hollow fiber membrane 11 in which the broken portion 12 is generated. In FIG. 3, it is a hollow fiber membrane from which the symbol M has been cut off. As a result, two open ends 11a and 11b are formed in the hollow fiber membrane 11, and the hollow portions 13a and 13b are opened.
Next, a resin injection nozzle 40 having an outer diameter smaller than the inner diameter of the hollow fiber membrane 11 is connected to the resin injector 60, and as shown in FIG. 4A, from the end portion 11a (11b) opened by excision. , Insert the resin injection nozzle 40.
Then, as shown in FIG. 4B, the repair resin 50 having a viscosity before curing of 10 mPa · s or more and 6,000 mPa · s or less at room temperature is injected from the resin injection nozzle 40 into the hollow portion 13a (13b). .. After the injection, the resin injection nozzle 40 is pulled out from the hollow fiber membrane 11, and the repair resin 50 is cured in a state where the injected repair resin 50 closes the hollow portion 13a (13b). In this way, as shown in FIG. 4C, the hollow fiber membrane M including the damaged portion 12 is cut off and the hollow portion 13a (13b) of the hollow fiber membrane 11 opened is closed by the cured repair resin 52, and the hollow fiber is formed. The membrane module is repaired.

Here, as shown in FIG. 3, when the hollow fiber membrane M including the damaged portion 12 is cut from the hollow fiber membrane 11, the potting resins 21a and 21b are newly opened from the ends 11a and 11b by the cutting. _{It is preferable that the length L 1} of the hollow fiber membrane up to the above is in the range of 20 to 100 mm. When L ₁ is 20 mm or more, the hollow fiber membrane 11 can be repaired by suppressing bending of the root of the hollow fiber membrane 11 during the work of sealing the hollow fibers 13a and 13b with the repair resin 50. Trouble such as damage to the root is unlikely to occur. On the other hand, when L ₁ is less than 100 mm, the resin injection nozzle 40 can be easily inserted. Further, when the repaired hollow fiber membrane module 10A is immersed in, for example, a water tank to be treated and air scrubbing cleaning is performed, the repaired hollow fiber membrane 11 is less likely to swing excessively. Therefore, rubbing against other hollow fiber membranes 11 due to excessive rocking is suppressed, and damage to the hollow fiber membrane 11 due to large bending at the root is also reduced. When cutting a part in the length direction including the damaged portion 12, it is preferable to determine the cutting position so that _{L 1 is within the range of 20 to 100 mm in consideration of the above points.}

Further, as shown in FIG. 4A, when the resin injection nozzle 40 is inserted from the end 11a (11b) of the hollow fiber membrane opened by excision, the tip of the resin injection nozzle 40 is at least the potting resin 21a. It is preferable to insert the resin injection nozzle 40 until it reaches (21b). If the tip of the resin injection nozzle 40 reaches at least the potting resin 21a (21b), the hollow fiber membrane 11 can be prevented from bursting when the repair resin 50 is injected, and the repair resin 50 is the hollow fiber membrane 11. It is also possible to prevent leakage through the inner membrane surface to the outside of the membrane.

The outer diameter of the resin injection nozzle 40 shown in FIG. 4A is preferably 0.2 mm or more, and is preferably 0.1 to 0.5 mm smaller than the inner diameter of the hollow fiber membrane 11. When the outer diameter of the resin injection nozzle 40 is 0.2 mm or more, the resin injection nozzle 40 is smoothly inserted from the ends 11a and 11b without breaking. Further, if the outer diameter of the resin injection nozzle 40 is larger than the inner diameter of the hollow fiber membrane 11, it becomes difficult to insert the resin injection nozzle 40 into the hollow portions 13a and 13b, and the hollow fiber membrane 11 may be damaged.
The inner diameter of the resin injection nozzle 40 is preferably 0.5 mm or more and 2.0 mm or less. When the inner diameter of the resin injection nozzle 40 is 0.5 mm or more, the repair resin 50 can be injected even if a lower pressure is applied. On the other hand, when the inner diameter of the resin injection nozzle 40 is 2.0 mm or less, sudden injection of the repair resin 50 is unlikely to occur even if a higher pressure is applied, and the hollow fiber membrane 11 is caused by the rapid injection of the repair resin. Eliminates the risk of bursting from the inside. Further, when the inner and outer diameters of the resin injection nozzle 40 are within the above range, the repair resin 50 is less likely to leak from the gap between the resin injection nozzle 40 and the hollow fiber membrane 11 during injection.
The tip of the resin injection nozzle 40 is preferably not sharp so as not to damage the hollow fiber membrane. An example is one in which the tip of an injection needle is smoothed with a gold file.
The resin injector 60 may be a known resin injector, and is not particularly limited as long as the repair resin 50 can be injected.

The resin used as the repair resin 50 is not particularly limited, but specifically, solvent volatilization type, moisture curing type, heat curing type, curing agent mixed type, ultraviolet curing type, and heat melting type resins are used. The repair resin 50 preferably contains at least one selected from each of these resins.

The viscosity of the repair resin 50 before curing is 10 mPa · s or more and 6,000 mPa · s or less at room temperature (° C.), but more preferably 15 mPa · s or more and 5,000 mPa · s or less, and 20 mPa · s or more. It is more preferably 2,000 mPa · s or less. When the viscosity before curing is 10 mPa · s or more at room temperature, the injected repair resin 50 is held in the hollow portions 13a and 13b of the hollow fiber membrane 11, so that the repair resin 50 flows out in the direction of gravity. , Trouble such as dripping and adhering to unintended parts is unlikely to occur. Further, when it is 6,000 mPa · s or less, it can be smoothly injected by the resin injection nozzle 40, and further, it becomes easy to impregnate the inner layer of the hollow fiber membrane 11, so that sufficient pressure resistance strength of the repaired portion can be obtained.
In addition, in this specification, a viscosity is a value measured in accordance with JIS Z 8803: 2011.

By the way, as shown in FIG. 5A, when the repair resin 50 having a viscosity before curing of 10 mPa · s or more and 50 mPa · s or less at room temperature is injected into the hollow portion 13a (13b) from the resin injection nozzle 40, The hollow fiber membrane 11 is impregnated with the repair resin 50, and the hollow portion 13a (13b) may communicate with the water flow channel 22a (22b). Further, the hollow portion 13a (13b) communicates with the water flow channel 22a (22b) depending not only on the viscosity but also on the film structure of the hollow fiber membrane 11, the physical properties of the repair resin 50, or the usage conditions such as temperature and humidity. There is.
In this case, after the hollow fiber membrane 11 is impregnated with the repair resin 50, the repair resin 50 is injected again, and the repair resin 50 is cured while the hollow portions 13a (13b) are closed. It is preferable because it has excellent properties and pressure resistance of the repaired part.

As shown in FIG. 5B, when the resin injection nozzle is inserted into the hollow portion 13a (13b), at least the tip of the resin injection nozzle 40 reaches or ends the potting resin 21a (21b). It is preferable that the repair resin 50 injected into the water is reached. If the resin injection nozzle 40 is inserted into the hollow portion 13a (13b) until it reaches a position satisfying any of the above, the hollow fiber membrane 11 can be prevented from bursting when the repair resin 50 is injected, and further repair can be performed. It is possible to prevent the resin 50 for permeating the inner membrane surface of the hollow fiber membrane 11 and leaking out of the membrane.

As shown in FIG. 1, the hollow fiber membrane module repaired by this method includes a plurality of hollow fiber membranes 11 and potting resins 21a and 21b for fixing the hollow fiber membranes 11 to the water collecting portions 20a and 20b. , At least one part of the hollow fiber membrane 11 in the length direction is cut off. Further, as shown by enlarging the portions (I) and (II) in FIG. 1 in FIG. 2, the hollow portions 13a and 13b opened by excision are closed with the cured repair resin 52, respectively.

Further, as shown in FIG. 4C, the hollow fiber membrane of the hollow fiber membrane module repaired by this method is among the hollow fiber portions 13a (13b) in which the hollow fiber membrane M including the damaged portion 12 is cut off and opened. At least a part of the portion where the outer periphery of the hollow fiber membrane 11 is in contact with the potting resin 21a (21b) is closed with the cured repair resin 52. That is, of the hollow portions 13a (13b), at least a part of the hollow portions 13a (13b) on the potting resin 21a (21b) side of the potting interface 23a (23b) is blocked by the cured repair resin 52. There is. When the hollow portions 13a and 13b are closed by the cured repair resin 52 in this way, the filtered water side and the water to be treated side are separated, and the separation / filtering performance of the hollow fiber membrane is maintained.

As shown in FIG. 4C, the hollow fiber membrane module 10A repaired by this method is a portion of the hollow portion 13a (13b) where the outer periphery of the hollow fiber membrane 11 is not in contact with the potting resin 21a (21b). _{The length L 2} of the portion closed by the cured repair resin 52 is preferably 30 mm or less, and more preferably 10 mm or less. The hollow fiber membrane of the portion blocked by the cured repair resin 52 is physically harder than the adjacent unrepaired hollow fiber membrane, but if _{the length of L 2} is 30 mm or less, air scrubbing cleaning is performed. When carried out, it is preferable because the hollow fiber membrane of the closed portion is less likely to rub against other adjacent hollow fiber membranes around it, and it is less likely to bend at the portion fixed to the water collecting portion of the hollow fiber membrane module. Therefore, it is preferable.

As shown in FIG. 6, the hollow fiber membrane module 10A repaired by this method repairs only the portion of the hollow portion 13a (13b) where the outer circumference of the hollow fiber membrane 11 is in contact with the potting resin 21a (21b). The resin for use may be injected and cured. That is, the hollow portion 13a (13b) may be closed by the cured repair resin 52 only at the hollow portion 13a (13b) on the potting resin 21a (21b) side of the potting interface 23a (23b). Also in this case, since the hollow portions 13a and 13b are closed by the cured repair resin 52, the filtered water side and the water to be treated side are separated, and the separation / filtering performance of the hollow fiber membrane is maintained. Further, even when the air scrubbing cleaning is performed, the hollow fiber membrane of the closed portion is less likely to rub against other adjacent hollow fiber membranes around it.

The form of the hollow fiber membrane module to be repaired is not limited. For example, as shown in FIGS. 7 and 8, the filtered water collected in the upper water collecting portion 20a without providing the water pipes 30a and 30b. An example thereof is a hollow fiber membrane module 10B in which only the water intake port 24 is taken out. In this case, after cutting the hollow fiber membrane M including the damaged portion 12, only the hollow portion 13a communicating with the upper water collecting portion 20a where the filtered water is collected is closed with the repair resin 50. Often, the hollow portion 13b on the lower water collecting portion 20b side that does not communicate with the upper water collecting portion 20a does not have to be closed. In the case of the hollow fiber membrane module 10B of this form, even if the hollow portion 13b is open, the water to be treated does not mix with the filtered water side. As long as the water to be treated does not mix from the end to the filtered water side in this way, only one of the two ends opened by excision may be closed and the other may be left open. It can be appropriately selected according to the form of the module.

(Action effect)
As described above, according to the method for repairing the hollow fiber membrane module of the present invention, a part in the length direction including the damaged portion 12 generated in the hollow fiber membrane 11 is excised, and the hollow fiber membrane is hollow and opened by excision. The repair resin 50 is injected into the portion, and the repair resin 50 is cured in the hollow portion, so that the hollow portion opened by excision is closed. Therefore, even if the hollow fiber membrane module repaired by this method is subjected to air scrubbing cleaning, the repair resin cured in the hollow fiber membrane does not come into direct contact with other hollow fiber membranes for repair. Since the hollow fiber membrane repaired with the resin is less likely to rub against other hollow fiber membranes, recurrence of breakage of the hollow fiber membrane can be reduced.
The hollow fiber membrane of the hollow fiber membrane module repaired by this method has a water collecting portion 20a of the hollow fiber membrane module, as compared with the case where the hollow fiber membrane is repaired by applying resin so as to cover the end of the cut hollow fiber membrane. Since it is difficult to bend at the portion fixed to 20b, it is possible to reduce the occurrence of a new damaged portion at the bent portion of the hollow fiber membrane.
In this method, since the repair resin 50 is cured in the hollow portions 13a and 13b, there is no possibility that the repair resin 50 adheres to other hollow fiber membranes 11 that are not to be repaired during the work, and the other hollow fiber membranes 11 are used. Since it is not necessary to separate the hollow fiber membrane 11 to be repaired, the workability is excellent. Furthermore, the application of this method is not limited by the shape and structure of the hollow fiber membrane module to which it is applied.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited thereto.

[Example 1]
A PVDF hollow fiber membrane module 10A (manufactured by Mitsubishi Rayon, product name "Stellapore 7600") having a pore diameter of 0.05 μm, an outer diameter of 1.65 mm, an inner diameter of 1.00 mm, and a membrane area of 40 m ^{2 was used.} The hollow fiber membrane 11 is fixed by the potting resins 21a and 21b and communicates with the water collecting portions 20a and 20b. Square pipes were used for the water pipes 30a and 30b. The outer diameter of the hollow fiber membrane module 10A is a width W1250 mm, a height H2000 mm, and a depth D30 mm. First, when the hollow fiber membrane module 10A was immersed in water, gas was sent into the hollow fiber membrane, and the position of the damaged portion 12 generated in the hollow fiber membrane 11 was specified according to the generation of air bubbles. As a result, 900 mm from the potting resin 21a. It turned out to be in the position of.
Then, the repair was carried out according to the method shown in FIG.
First sides of the potting resin 21a, the length L ₁ is the position of 50mm each from 21b, by cutting the respective hollow fiber membranes 11 in two places, removing the portion of the length direction of the hollow fiber membrane 11 including the damaged portion 12 ..
Next, the tip of the resin injection nozzle 40 (Terumo injection needle (21G, manufactured by Terumo Corporation)) with an outer diameter of 0.80 mm is attached to the resin injector 60 (Terumo syringe (registered trademark), capacity 1 mL, manufactured by Terumo Corporation). The repair resin 50 (Rocktite (registered trademark) 4305, viscosity 900 mPa · s, ultraviolet / moisture curable type, manufactured by Henkel) was produced by the above-mentioned cutting. Injection was performed from the end portion 11a (11b) into the hollow portion 13a (13b). Here, the tip of the resin injection nozzle 40 was inserted until it reached at least the potting resin 21a (21b).
After visually confirming that the repair resin 50 reaches the potting resin 21a (21b) and the hollow portion 13a (13b) is closed, the humidity existing environment (temperature: 20 ° C., humidity 50%) The repair resin 50 was cured by allowing it to stand underneath for 2 hours.
The hollow fiber membrane module 10A of FIG. 1 repaired in this way was transferred into water, and air was supplied from the water intake port 24 so that the internal pressure of the hollow fiber membrane module 10A was 100 kPa, and a damage inspection was performed. In the damage inspection, no air leakage was confirmed from the ends 11a and 11b, and it was confirmed that the hollow portions 13a and 13b of the hollow fiber membrane 11 were securely closed.
In this example, the viscosity was measured in accordance with JIS Z 8803: 2011.

[Example 2]
The repair resin 50 was formed in the hollow portion 13a by the same method as in Example 1 except that Loctite (registered trademark) 4304 (viscosity 20 mPa · s, ultraviolet / moisture curable type, manufactured by Henkel) was used as the repair resin 50. It was injected into (13b). After injecting the repair resin 50, the hollow fiber membrane was impregnated with the repair resin 50 by allowing it to stand for 10 minutes in a humidity-existing environment (temperature: 20 ° C., humidity 50%). Then, the repair resin 50 was injected again, the hollow portion 13a (13b) was closed, and the resin 50 was cured in the same manner as in Example 1. Here, the resin injection nozzle 40 was inserted until the tip of the resin injection nozzle 40 reached at least the repair resin 50.
When the hollow fiber membrane module 10A repaired in this way was inspected for damage in the same manner as in Example 1, no air leakage was confirmed from the ends 11a and 11b, and the hollow fiber membranes 13a and 13b of the hollow fiber membrane 11 were found. It was confirmed that it was definitely blocked.

[Examples 3 and 4, Comparative Examples 1 to 3]
As shown in Table 1, the repair resin 50 was changed, and the method for repairing the hollow fiber membrane module of the present invention was carried out. In Table 1, Examples / Comparative Examples in which the number of injections (times) is “1” are the same as in Example 1 except that the repair resin 50 is changed, and the number of injections is “2”. -The comparative example was carried out in the same manner as in Example 2 except that the repair resin 50 was changed.
The hollow fiber membrane module 10A repaired in Example 4 was aerated (air scrubbing) on activated sludge under the condition of a linear velocity of 100 m / hr for one year, and then air was blown under the condition of an internal pressure of 100 kPa. It was supplied and inspected for damage. No air leakage was confirmed from the end portions 11a and 11b and the hollow fiber membranes adjacent to them, and no new damaged portion was detected.
When air leakage was confirmed by the damage inspection, it was indicated by "○" in Table 1, and when air leakage was detected, it was indicated by "x" in Table 1.

[Comparative Example 4]
After excising the damaged portion of the hollow fiber membrane 11, the resin is melted by heating using Scotch-Weld Hot Melt Adhesive 3748-Q (manufactured by 3M Ltd.) as the repair resin 50, and the cut surface of the hollow fiber membrane is melted. It was applied so as to cover the surface and repaired. After the repair, a damage inspection was conducted under the same conditions as in Example 1, and no air leakage from the repaired portion was confirmed. Next, the repaired hollow fiber membrane module was aerated (air scrubbing) on activated sludge at a linear velocity of 100 m / hr for one year, and then a damage inspection was performed from the inside of the hollow fiber membrane with 100 kPa of compressed air. Air leakage was confirmed from the hollow fiber membrane around the repaired part and the hollow fiber membrane on the potting resin side of the repaired part.

As shown in Table 1, the hollow fiber membrane modules of Examples 1 to 4 repaired using a repair resin having a viscosity of 10 mPa · s or more and 6,000 mPa · s or less are appropriately repaired by this method and are sufficient. It had pressure resistance.
The hollow fiber membrane modules of Example 2 and Example 3 in which the hollow fiber membrane was impregnated with the repair resin after the first injection of the repair resin and then the repair resin was injected again and cured were also appropriately repaired. , Had sufficient pressure resistance.
Since the hollow fiber membrane module of Example 4 had sufficient pressure resistance even after being aerated by activated sludge for one year, the repaired hollow fiber membrane was bent at the portion fixed to the water collecting portion. Or, the hollow fiber membrane rubbed against the surrounding hollow fiber membrane, so that no new damaged portion was generated.
It is probable that the hollow fiber membrane module of Comparative Example 1 using the repair resin having a viscosity higher than 6,000 mPa · s had insufficient pressure resistance because the inner layer of the hollow fiber membrane was not impregnated with the repair resin. ..
In the hollow fiber membrane module of Comparative Example 2 using a repair resin having a viscosity of less than 10 mPa · s, the inner layer of the hollow fiber membrane was excessively impregnated with the repair resin, and the hollow portion communicated with the potting resin.
In the hollow fiber membrane module of Comparative Example 3 using a repair resin having a viscosity of less than 10 mPa · s, the inner layer of the hollow fiber membrane was excessively impregnated with the repair resin, and after the first injection of the repair resin, the hollow fiber membrane module was repaired again. Even when the resin was injected and cured, the hollow portion communicated with the potting resin.
In the hollow fiber membrane module of Comparative Example 4 in which the molten resin was directly applied to the cut surface, the repair resin and the surface of the hollow fiber membrane rubbed against each other during air scrubbing, and the hollow fiber membrane was formed starting from the potting resin side of the repaired portion. It is probable that it was bent.

11 Hollow fiber membranes 11a, 11b Ends of hollow fiber membranes caused by cutting 12 Broken parts 13a, 13b Hollow fiber membranes opened by cutting 20a, 20b Water collecting parts 21a, 21b Potting resin 22a, 22b Flow channel 23a , 23b Potting interface 24 Intake port 40 Resin injection nozzle 50 Repair resin 52 Hardened repair resin 60 Resin injector

Claims (3)

A method of repairing a hollow fiber membrane module including a plurality of hollow fiber membranes and a potting resin for fixing the hollow fiber membranes.
A part of the hollow fiber membrane in the length direction including the damaged portion generated in the hollow fiber membrane is cut off.
A resin injection nozzle is inserted from the end of the hollow fiber membrane opened by excision.
A repair resin having a viscosity before curing of 10 mPa · s or more and 6,000 mPa · s or less at room temperature is injected from the resin injection nozzle.
A method of curing the repair resin while the repair resin closes the hollow portion of the hollow fiber membrane.
A method for repairing a hollow fiber membrane module in which the resin injection nozzle is inserted until the tip of the resin injection nozzle reaches at least the potting resin. The repair resin having a viscosity before curing of 10 mPa · s or more and 50 mPa · s or less at room temperature is injected into the hollow portion of the hollow fiber membrane from the resin injection nozzle, and the repair resin is applied to the hollow fiber membrane. The method for repairing a hollow fiber membrane module according to claim 1, wherein the repair resin is injected again after impregnation. The hollow fiber membrane is provided with a plurality of hollow fiber membranes and a potting resin for fixing the hollow fiber membrane, and at least one part of the hollow fiber membrane in the length direction is excised and opened by excision. The part is a hollow fiber membrane module that is closed with repair resin.
Of the hollow portion, at least a part of the portion where the outer circumference of the hollow fiber membrane is in contact with the potting resin is closed with the repair resin.
A hollow fiber membrane module in which the length of a portion of the hollow portion in which the outer periphery of the hollow fiber membrane is not in contact with the potting resin and which is closed by the repair resin is 30 mm or less.

Images