JP2920543B2 - Method for manufacturing hollow fiber membrane module - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing a hollow fiber membrane module reinforced by fixing its outermost end to two layers with different materials.

(Prior art) A hollow fiber membrane module, which is one of the typical types of membrane separation modules, has a large membrane area per unit volume and a simple sealing mechanism for separating a permeate from a stock solution to be treated. It has various advantages such as Conventionally, such a hollow fiber membrane module is prepared by bundling a plurality of hollow fiber membranes, then loading the hollow fiber membrane into a case, injecting and filling a sealant, fixing the hollow fiber membranes to each other, and fixing the ends of the case. Although manufactured by hermetic sealing, a sealing agent for bonding and fixing the hollow fiber membrane is required to have a high degree of pressure resistance and durability, and is usually of relatively high hardness.

However, when the module manufactured in this manner is used by passing the stock solution through the inside of the hollow fiber membrane under a combination of relatively high temperature and pressure conditions, stress concentration occurs at the interface between the sealant and the hollow fiber membrane and the hollow fiber There was a problem that the film was damaged.

In other words, when internal pressure is applied to the module at high temperature, a force acts to expand the hollow fiber membrane in the circumferential direction, but the part fixed with the relatively hard sealant does not deform at all. Since the hollow fiber membrane part is freely deformed according to the magnitude of the stress, a sharp difference in the amount of deformation occurs at the interface, and from this part the hollow fiber membrane breaks along its length or breaks along the interface. There was a drawback that the strength originally possessed by the hollow fiber membrane could not be effectively utilized due to breakage of the yarn or the like.

Several methods are known as methods for reinforcing the bonding end. For example, Japanese Patent Application Laid-Open No. 59-4403 discloses a method in which a resin is applied to and impregnated on the surface of a hollow fiber near an adhesive fixed end to prevent breakage of a film due to accumulation of SS components on the outer surface. Although this method can prevent the membrane from deteriorating due to the bending moment of the outer periphery of the bundle and the heat generated when the ends are fixed, it improves the pressure resistance of the module against the pressure from the inside of the hollow fiber membrane. It is difficult to make it happen. Japanese Utility Model Application Laid-Open No. 61-132002 discloses a method of reinforcing a module by forming an elastic layer in contact with a layer to which a hollow fiber membrane bundle is fixed. Although this method is an effective method to reinforce the interface between the sealant and the hollow fiber membrane,
There is a problem that it is difficult to form an elastic layer having a uniform thickness at a portion where the hollow fiber membranes are in close contact with each other, especially at the central portion of the hollow fiber membrane bundle, and the membrane is likely to be damaged at this portion. This is due to the fact that when filling the end of the module with the liquid elastic rest before curing, the liquid is difficult to distribute to the portions where the hollow fiber membranes are in close contact with each other. In addition, the fact that the thickness of the elastic layer is not uniform is not preferable from the viewpoint of a so-called “dead space”. The treatment liquid is likely to stagnate in areas where the thickness of the elastic layer is uneven and holes or cavities are formed, which may cause spoilage or propagation of bacteria.This problem is serious in the pharmaceutical and food fields. Become.

(Problems to be Solved by the Invention) The present invention does not provide a hollow fiber membrane module having a sufficient pressure resistance against pressure from the inside of the hollow fiber membrane and having a structure in which dead space does not occur, and a method for manufacturing the same. It is assumed that.

(Means for Solving the Problems) As a result of intensive studies to overcome the above problems, the present inventors have completed the present invention. That is, the first feature of the present invention is that an elastic layer having a uniform thickness is formed at the end of the hollow fiber membrane bundle of the hollow fiber membrane module adjacent to the sealing portion, and thereby the inside of the hollow fiber membrane is formed. It has been found that it has a sufficient pressure resistance against pressure from the outside and can solve the problem of dead space. Further, in the present invention, in order to form the elastic layer having a uniform thickness, a plurality of fillers are interposed at the ends of the hollow fiber membrane bundle and fixed with a sealant, and the ends of the hollow fiber membrane bundle are divided and arranged. The second feature is that the fixing is performed as it is.

The elastic layer, which is one of the features of the present invention, is provided in contact with the sealing portion and has a uniform thickness over the entire bundle. In this case, the thickness of the elastic layer is 5 to 50 mm, preferably 5 to 50 mm in order to reduce stress concentration at the interface between the sealant and the hollow fiber membrane.
10mm is appropriate. The term “uniform thickness” as used herein means that no holes or depressions serving as dead spaces are generated. From a empirical viewpoint, it is preferable that the difference between the maximum value and the minimum value of the thickness of the entire elastic layer be kept within 3 mm as a range in which these holes and depressions do not substantially cause a problem. Examples of the material of the elastic body include silicone, urethane, and other rubber-like substances.

Next, the manufacturing method will be described. The production method of the present invention is as follows.

A method for manufacturing a hollow fiber membrane module in which both ends of a hollow fiber membrane bundle inserted into a case are fixed to the case by a sealant, and an elastic layer is provided adjacent to the sealing portion in the case. First, the hollow fiber membrane bundle is filled with a plurality of fillers at the end thereof, and fixed with a sealant in a state where the membrane bundle end is divided into a plurality of parts, and thereafter, the hollow fiber membrane which has become a seal portion in the case A method for manufacturing a hollow fiber membrane module, comprising forming an elastic layer at an end of a bundle. This method is an effective method for producing a hollow fiber membrane module having the above-described features, and is characterized in that a filler is fixed to a hollow fiber membrane bundle while being sandwiched. As a result, the film bundle is fixed in a divided state, and the liquid elastic body before curing is uniformly distributed and cured throughout the bundle through the gap,
As a result, an elastic layer having a uniform thickness is formed adjacent to the seal portion. The form of the divisional arrangement is not particularly limited as long as it promotes this, but the form shown in FIG. 1 is appropriate from the viewpoint of minimizing the contact points between the hollow fibers. . At this time, the size of the gap depends on the viscosity of the liquid elastic material to be filled,
It is preferable to take 1 mm or more. It is preferable that the size of each of the divided hollow fiber membrane bundles is as small as possible, but it depends on the number of hollow fiber membranes, the size of the case, or the workability during manufacturing. However, if this is made too large, the thickness of the elastic layer in each bundle becomes non-uniform. For example, in FIG. Suitably it comprises a membrane, preferably two to three rows of hollow fiber membranes.

As described above, in order to fix the hollow fiber membrane (4) in a divided state, the filler (1) is fixed between the bundles with a sealant so as to obtain a desired divided state. As the agent (2), a thermosetting resin such as an epoxy resin, an unsaturated epoxy resin, an unsaturated polyester resin, and a phenol resin is suitable. In addition, the size, shape and material of the filler sandwiched between the bundles are determined by how the hollow fiber membrane bundle is divided, but the material is the same as the sealant (for example, It is preferable to use epoxy resin), polyethylene, polypropylene, or the like, and the shape may be a net shape or a plate shape to improve the adhesion to the sealant. For example, as shown in FIG. 1, if the hollow fiber membrane is fixed with epoxy resin while being divided and arranged, a width of 10
An epoxy resin plate (1) having a thickness of about 1 mm and a thickness of about 1 mm is formed into a bundle such that each row of the hollow fiber membrane bundle is composed of 5 to 6 rows, preferably 2 to 3 rows of hollow fiber membranes (4). Scissors.

FIG. 2 is a front view showing a state where the filler (1) is inserted into the hollow fiber membrane bundle (4), and FIG. 3 is a side view thereof.

Next, the portion of the filler protruding from the outer periphery of the bundle is cut so that the hollow fiber membrane bundle can be inserted into the case, and inserted into the case. At this time, the position of each filler (1) is adjusted so that these fillers are hidden in the sealant after the sealant is injected, and a gap is left between the hollow fiber membrane bundles even after the sealant is cured. And then insert it into the case. Thereafter, a liquid sealant before curing is injected and cured. A known method such as a centrifugal bonding method can be employed for this.

When the filler is of the same material as the sealant, or when it is completely embedded in the sealant, it cannot be clearly seen as shown.

After the curing of the sealant is completed, an elastic layer (3) is formed at a position adjacent to the sealant layer (2) (first).
Figure). As the elastic body, a rubber-like substance such as silicone or urethane can be used as described above.
These are usually fixed in a desired form by curing a liquid material before curing by heating or the like. At this time, in order to further facilitate the distribution in the hollow fiber membrane bundle, a predetermined diluent may be added to lower the viscosity of the liquid elastic body. There are various methods to inject this liquid elastic body into the module,
A simple method is to attach a vinyl tube or the like to the flux port provided at the end of the case and pour it in by the head difference.

By holding the module case vertically and heating it after the liquid is completely injected to cure the elastic body,
An elastic layer having a uniform thickness is formed on the entire bundle. The amount of the liquid elastic material injected at this time is adjusted so that the thickness of the cured elastic material layer is 5 to 50 mm, preferably 5 to 10 mm. Also, when trying to inject the liquid elastic body more completely into the details of the hollow fiber membrane bundle or when the viscosity of the liquid elastic body is relatively high, the centrifugal force was used in the same manner as when the sealant was injected. An injection can also be performed.

Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to these examples.

(Example 1) Polyethylene hollow fiber type microfiltration membrane (outside diameter 3 mm, inside diameter 2
mm, length 1300mm, average pore diameter 0.2 micron)
It was inserted into a polysulfone case having a thickness of 0 mm, a thickness of 5 mm, and a length of 1100 mm. To both ends of this membrane bundle, thickness 1mm, length 100mm, width
Six 10 mm epoxy plates were inserted at equal intervals (FIG. 2), and the portion protruding from the membrane bundle was cut. Furthermore, this 6
After the sealant is injected into the sealant, adjust the position of these plates so that they can completely enter the sealant, place polyethylene cups on both ends of the module, and centrifuge the liquid. Epoxy resin was injected. After the injection of the resin was completed, the resin was cured at 90 ° C. for 4 hours. The polyethylene cup was removed, and both ends of the module were cut to obtain a sealed hollow fiber membrane module with the membrane bundle divided into seven sections.

Next, the module was set up vertically, and 75 cc of the liquid silicone resin before curing was injected from the flux opening at the lower end.
After leaving at room temperature for 1 hour, the resin was cured by treating at 90 ° C. for 4 hours. After further treatment at 50 ° C. for 10 hours to completely cure the silicone resin, the same treatment was applied to the other end of the module to form a silicone resin elastic layer having a thickness of about 1 cm.

3.5 kg / cm ² input pressure and 3.0 kg output pressure
After operating for 1 hour in pure water at 70 ° C./cm ² and 70 ° C., air pressure was applied from the drainage side of the module.
Further, after operating for 9 hours under the same operating conditions, the same inspection was performed. As a result, it was determined that there was no air leak from the end face and no breakage of the film. When the module after operation was disassembled and the state of the membrane was observed, no breakage of the membrane was observed. The thickness of the silicone elastic layer was 8 to 10 mm when measured at 10 locations, and a substantially uniform layer was formed with no dead space.

(Examples 2 to 3) A module was produced in the same manner as in Example 1 except that the number of epoxy plates sandwiched in the film bundle was changed to 8 (Example 2) and 10 (Example 3). After operating for 1 hour under the same conditions as in Example 1 and further operating for 9 hours and performing an air pressurization test, it was determined that there was no air leak from the module end face and that there was no damage to the film. Was. When the module after operation was disassembled, no breakage of the membrane was observed, and the thickness of the silicone elastic layer was 8 in Example 2.
1111 mm, and 9 to 11 mm in Example 3. In each case, a substantially uniform layer was formed and there was no dead space.

(Comparative Example) A module was manufactured in the same manner as in Example 1 except that the epoxy plate was not sandwiched between the membrane bundles. After operating for 1 hour under the same conditions as in Example 1, an air pressurization test was performed from the drainage side. As a result, many air leaks were observed from the end face. When the module was disassembled and examined, it was found that almost no silicone was spread at the center of the film bundle, and a dozen or so films were ruptured at the interface of the bonded portion. The silicone elastic layer is 0 mm at the center and 12 to
It had a thickness of 15 mm and had a structure in which the center was dead space.

(Effect of the Invention) According to the present invention, a hollow fiber membrane module having a sufficient pressure resistance against pressure from the inside of the hollow fiber membrane and having a structure in which dead space does not occur can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic view showing one end of a hollow fiber membrane module of the present invention. FIG. 2 is a front view showing a state in which the filler is inserted into the hollow fiber membrane bundle, and FIG. 3 is a side view thereof. 1 Filler 2 Sealant 3 Elastic layer 4 Hollow fiber membrane

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B01D 63/02 B01D 63/00 500

Claims (1)

(57) [Claims] 1. A hollow fiber membrane module wherein both ends of a hollow fiber membrane bundle inserted into a case are fixed to the case by a sealant, and an elastic layer is provided adjacent to the sealing portion in the case. The hollow fiber membrane bundle is first filled with a plurality of fillers at the end, and the membrane bundle end is divided into a plurality of parts and fixed with a sealant, and then becomes a seal part in the case. A method for producing a hollow fiber membrane module, comprising forming an elastic layer at the end of a conventional hollow fiber membrane bundle.