JP3147600B2 - Manufacturing method of hollow fiber membrane - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a hollow fiber membrane.
In particular, the present invention relates to a method for cleaning a hollow fiber membrane suitable for removing a solvent remaining inside the hollow fiber membrane.

[0002]

2. Description of the Related Art Conventionally, the following method has been known as a cleaning method for removing a solvent remaining inside a hollow fiber membrane. In this method, a hollow fiber membrane is stored in a washing basket, and the washing basket is immersed in an immersion tank containing washing water. Then, the hollow fiber membrane is washed by heating and maintaining the washing water, replacing the washing water in the immersion tank, and repeatedly dehydrating the hollow fiber membrane several times.

[0003]

However, the above-described cleaning method has the following problems. That is, since the conventional cleaning method involves immersing the hollow fiber membrane in a hot water bath, the time required for the cleaning water to pass through the inside of the hollow fiber membrane and allow the solvent to flow out, and the time required for immersion in the immersion water tank. The processing time required for cleaning the hollow fiber membrane is long (for example, about 12 hours), such as the time required to replace the washing water several times. In addition, since the cleaning water hardly convects inside the immersion water tank, cleaning unevenness may occur. In addition, since it is difficult for the washing water to flow into the inside of the hollow fiber membrane and for the solvent to hardly flow out, it is necessary to increase the ratio of the washing water to the hollow fiber membrane. Therefore, a large immersion water tank must be used. Further, since the washing water is replaced several times by a large immersion water tank, a large amount of washing water is consumed, and there is a problem that the cost for washing is increased.

The present invention has been made in view of such circumstances, and a method for manufacturing a highly reliable hollow fiber membrane that can reduce the washing time, reduce the consumption of washing water, and have no unevenness in washing. It is intended to provide.

[0005]

The present invention has the following configuration in order to achieve the above object. That is, the invention according to claim 1 includes the steps of:
Store it in a bundle in a washing basket through which washing water can pass, and
While rotating the cleaning basket, wash water from the surroundings
Of hollow fiber membranes, which are sprayed and washed
Is the way .

[0006] The invention described in claim 2 is the invention according to claim 1.
The method of manufacture according to the hollow fiber membrane is one that is polysulfone.

[0007] The invention according to claim 3 provides the invention according to claim 1.
Alternatively, in the production method according to claim 2, the hollow fiber membrane has an outer diameter of 100 to 800 µm and a thickness of 5 to 150 µm.
m and the average pore diameter are 0.001 to 5 μm.

[0008]

The operation of the present invention is as follows. According to the present invention, by storing the hollow fiber membranes in a bundle in a washing basket through which the washing water can pass, and by spraying the washing water from the surroundings to the washing basket while rotating the washing basket, the inside of the washing basket is Wash water is forcibly supplied to the hollow fiber membrane, and centrifugal force is generated by the rotation of the washing basket, so that the solvent inside the hollow fiber membrane is forcibly discharged together with the wash water.

[0009]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a horizontal sectional view of a cleaning apparatus using the method for producing a hollow fiber membrane according to the present embodiment, and FIG. 2 is a sectional view taken along line GG in FIG. As shown in the figure, the washing apparatus includes a main body 10 forming a washing work chamber, a washing water tank 20 for heating and storing washing water, a turntable 30 for transporting the hollow fiber membrane to each work chamber, and Six turntables 40 provided on the turntable 30, three jetting means 50 for jetting heated cleaning water to the hollow fiber membrane, a cooling means 60 for cooling the hollow fiber membrane, and a hollow fiber membrane The washing basket 70 is stored and held and placed on each rotary table 40.

Hereinafter, the configuration of each unit will be described in detail. FIG.
As shown in FIG. 1, the main body 10 is configured in a box shape with a base plate 11 installed on a floor surface of a factory or the like, a top plate 12, and four side walls 13, and a turntable as a working unit. Covers 30. Also, each side wall 13 has an upper panel 13a.
, An intermediate panel 13b, and a lower panel 13c. The intermediate panel 13b, which is a portion forming each of the working chambers described later, is double-structured and filled with a heat insulating material. In addition, each intermediate panel 13b is provided with a viewing window 15 with a cover, so that the state of each work room can be observed from outside.

The turntable 30 is formed in a disk shape, and has a shaft 31 protrudingly fixed at a rotation center position thereof. The lower end of the shaft 31 is rotatably supported by a support 16 provided on the base plate 11 via a bearing 17, and the upper end of a support plate 18 provided on the top plate 12.
Are supported by bearings 19 via bearings 19. This shaft 31
Is connected to a motor 39 equipped with an indexing mechanism (not shown), whereby the turntable 30 is driven to rotate. Then, the rotary table 40 is transported to each of the working chambers described below.

A cover 32 having substantially the same diameter is fixedly provided on the shaft 31 above the turntable 30, and a hexagonal chamber partition plate 33 is attached at the center of the turntable 30 so as to cover the shaft 31. ing. And
A partition plate 34 is connected and fixed between the turntable 30 and the cover 32 so as to form each work chamber in a fan shape with the room partition plate 33 as a center side in a horizontal view. Rotate. The internal space of the main body 10 is partitioned into six working chambers by these partitioning plates 34, and the loading / unloading chambers A,
A first cleaning room B, a first dehydration room C, a second cleaning room D, a third cleaning room E, and a second dehydration room F are provided, respectively. In addition,
When the turntable 30 is in a predetermined phase, a non-rotating partition wall 35 having a sealing member is fixedly provided inside the main body 10 at a position facing the outer peripheral end of each partition plate 34, and the cleaning water in each work chamber is provided. Prevents water leakage.

A rotary table 40 provided on the turntable 30 is formed in a disk shape, and a rotary shaft 41 is protruded and fixed at a rotation center position. The shaft 41 is
The lower end is rotatably supported on the turntable 30 via a bearing 36, and the upper end is rotatably supported on the cover 32 via a bearing 37, and is connected to a motor 38 provided on the upper part of the cover 32 for rotation. Driven.

FIG. 3 is a plan view of the rotary table, and FIG.
Is an HH sectional view thereof. The rotary table 40 includes a cylindrical side plate 42, a support plate 43 having a shaft hole in the center thereof, and a plurality of round bars 44 each having a predetermined gap as shown in FIG. , Washing water is easy to fall down.

Next, each of the working rooms will be described. The loading / unloading chamber A has an opening formed in the intermediate panel 13b of the front side wall 13, and a shutter 14 is attached to the opening so as to be freely opened and closed. With the shutter 14 in the open state, the washing basket 70 containing the hollow fiber membrane is loaded or the washed basket 70 after washing is taken out.

The first cleaning chamber B is provided with a fixed injection means 50.
And the first washing of the hollow fiber membrane is performed. The injection means 50 will be described with reference to FIGS. Injection means 50
Are U-shaped vertical pipes 51 fixedly provided so as to be close to the outer peripheral edge of the turntable 30 and having a bent portion at the upper part, and two rows of horizontal pipes 52 in a horizontal posture connected to the bent portions.
And The vertical pipe 51 is connected through a pipe 22 laid under the turntable 30 to a first washing water tank 21 provided at the rear of the main body. And
The heated cleaning water is supplied from the first cleaning water tank 21 to the injection unit 50 by a circulation pump (not shown). Vertical piping 5
In 1, a plurality of flat nozzles 53 are provided so that the injection ports face the rotation center of the rotary table 40. A plurality of wide-angle flat nozzles 55 are provided in the upper horizontal pipe 52 via a free joint 54 so as to adjust the spray angle, so that the washing water is sprayed evenly to the washing basket 70. In addition, by making the injection angle of the wide-angle flat nozzle 55 adjustable, it is possible to cope with cleaning baskets 70 having different sizes.

In the second cleaning chamber D and the third cleaning chamber E, the same jetting means 50 as the first cleaning chamber B is fixedly provided, and the second cleaning water tank 23 and the third cleaning water tank 25 are respectively provided. Are connected through a pipe 24 and a pipe 26.

In the second dehydrating chamber F, a cooling means 60 is fixedly provided, and the hollow fiber membrane is cooled by injecting cooling water to the hollow fiber membrane before dewatering the hollow fiber membrane. The cooling means 60 is fixedly provided so as to be close to the outer peripheral edge of the turntable 30 similarly to the injection means 50, and is connected to a cooling water tank (not shown) via a pipe 61.

The water used for washing and cooling is as follows:
Water collecting tray 27 provided at the lower part of turntable 30
The water is discharged to a purified water tank (not shown) disposed outside and rearward of the main body 10 through a drain pipe 28 provided at a lower portion of the water. Therefore, the cleaning water after cleaning is purified, and is again guided to the cleaning water tank 20 and stored therein. Further, fresh water is supplied to the washing water tank 20 as needed.

FIG. 5 is a perspective view showing the cleaning basket. Hereinafter, the structure of the cleaning basket will be described with reference to the drawings. As shown in the figure, the cleaning basket 70 is formed in a box shape, the upper plate 72 is attached to the main body 71 via the hinge 74a, and the door plate 73 is attached to the upper plate 72 via the hinge 74b.
It can be opened and closed from one side to the top. A handle 75 is attached to the center of the upper plate 72 so that it can be easily put into and taken out of the cleaning device. A pair of snap locks 76 are attached to both lower side surfaces of the door plate 73, and are locked by metal fittings 77 attached to the main body 71.

A large number of small holes 78 are formed on the entire surface of the cleaning basket 70, and a wire net 79 is adhered to each surface of the cleaning basket 70. This prevents the sprayed washing water from directly hitting the hollow fiber membrane through the small holes 78 and damaging the hollow fiber membrane.

The cleaning operation in each working room of the cleaning apparatus configured as described above will be described. FIG. 6 is a diagram showing the process until the hollow fiber membrane is set in the washing basket 70.
Hereinafter, the setting state of the hollow fiber membrane will be described with reference to the drawings. As shown in an enlarged view in FIG. 6 (a), the hollow fiber membrane t immediately after being spun in the spinning process has a solvent of an injection liquid or a stock solution permeating into the inside. The material of the hollow fiber membrane t is, for example, polysulfone, polyethylene, polypropylene, or the like,
These outer diameters are 100 to 800 μm and the wall thickness is 5 to 15
It has a pore size of 0 μm and has an average number of pores of 0.001 to 5 μm, and the solvent has penetrated into the pores.

As shown in FIG. 6 (b), the hollow fiber membranes t are wrapped in a gauze G in a bundle state to form a cylindrical hollow fiber bundle T. The gauze G prevents surface damage of the hollow fiber membrane t at the time of washing or transportation, and holds the hollow fiber membrane t so as not to shift. Next, the hollow fiber bundles T are stacked inside the cleaning basket 70 without any gap as shown in FIG.
Is set on the device.

Next, the cleaning process will be described with reference to FIG. (1) First, the washing basket 70 is set on the turntable 40 in the loading / unloading chamber A on the front of the apparatus. The washing basket 70 is attached to the rotating table 40 so that centrifugal force is easily applied.
The two washing baskets 70 are placed on the outer side of the center of rotation, and are placed so as to face each other with the center of rotation therebetween in consideration of the rotation balance.

(2) Then, by turning on a switch (not shown), the turntable 30 is rotated in the counterclockwise direction, and the rotary table 40 on which the cleaning basket 70 is placed is transported to the first cleaning chamber B. Is done. Then, the cleaning water heated from each nozzle of the injection means 50 is supplied to the rotary table 4.
At the same time, the fuel is injected toward zero, and the turntable 40 starts rotating to perform cleaning. Here, the solvent remaining in the hollow fiber membrane t is removed by the injection of the washing water and the centrifugal force of the rotary table 40. Here, the number of rotations of the rotary table 40 is preferably rotated at 5 to 50 rpm during cleaning in order to increase the cleaning effect of the hollow fiber membrane t, and the temperature of the cleaning water is preferably 30 to 95 ° C. , 80-95
° C is more preferred. In addition, it is preferable that the injection amount of the cleaning water from the wide-angle flat nozzle 55 is injected at an injection speed of 50 liters / minute or more per room. The same applies to a second cleaning chamber D and a third cleaning chamber E to be described later. In addition,
During the first cleaning, the next cleaning basket 70 is set on the turntable 40 in the loading / unloading chamber A.

(3) After a lapse of at least 5 minutes, the first cleaning is completed, and the cleaning basket 70 is transported to the first dehydrating chamber C by the rotation of the turntable 30. At that time, the next washing basket 70 is carried into the first washing room B from the loading / unloading room A. Thereafter, the operation is sequentially repeated. The cleaning basket 70 conveyed to the first dehydrating chamber C is rotated at a speed of 50 rpm or more to enhance the cleaning effect, and is dehydrated by its centrifugal force. The same applies to the second dehydrating chamber F.

(4) After the dehydration in the first dehydration chamber C is completed, the turntable 30 is further rotated, and the cleaning basket 70 is sequentially transported to the second cleaning chamber D and the third cleaning chamber E. In the same manner as in B, the solvent contained in the hollow fiber membrane t is removed.

(5) The hollow fiber membrane t from which the solvent has been completely removed in the third washing chamber E is transported to the second dehydration chamber F, where the hollow fiber membrane t is cooled by the cooling means 60 before dehydration is started. And then completely dehydrated.

(6) Finally, the washing basket 70 that has been transported to the loading / unloading chamber A and washed out is taken out.
A new washing basket 70 is inserted, and the above-described series of operations is continuously repeated. According to the apparatus of the above embodiment, the cleaning of the hollow fiber membrane t can be completed in about 1.25 to 1.7 hours.

In the above-described embodiment, the cleaning basket 70 is transported by the turntable 30 and is a multi-stage cleaning type having six chambers. However, the present invention is not limited to this. For example, it may be a linear continuous conveyance, or a single-stage cleaning type in which cleaning and dehydration are performed by one fixedly arranged rotary table 40.

In the above embodiment, the used water is received by one water collecting tray 27, and the water purified by the purified water tank is stored in the washing water tank 20. The structure is as follows. May be. The water collecting tray 27 is separately arranged in each work room, and first, water used in the second dehydrating room F is sent to the third washing water tank 25, and then water used in the third washing room E is sent to the third washing room E. The water is sent to the second washing tank 23, and then the water used in the second washing chamber D is sent to the first washing tank 21. In addition, the first dehydration room C
By circulating the dewatered water to the first cleaning water tank 21, the cleaning water can be used more efficiently.

In the above-described embodiment, heated cleaning water is used to enhance the cleaning effect, but the cleaning water may be at room temperature. In this case, it is needless to say that the cooling means 60 need not be provided.

In the above-described embodiment, the hollow fiber bundle T is formed by bundling a large number of hollow fiber membranes t with both ends opened, but the present invention is not limited to this. For example, the hollow fiber membrane t may be wrapped in gauze in a wound state to form a hollow fiber bundle T.

Further, in the above-described embodiment, the hollow fiber bundle T is stored directly in the washing basket 70;
An intermediate pad may be interposed every several stages. As a result, the hollow fiber bundle T is stored more stably, and the hollow fiber membrane t
Damage can be further reduced.

The direction in which the hollow fiber bundle T is stored in the washing basket 70 may be any of the three directions shown in FIGS. 6C, 7A and 7B.

Next, in order to confirm the effect of the present invention, cleaning was performed under the following conditions. (Example 1) The outer diameter obtained in the spinning process was 460 μm, and the wall thickness was 80 μm.
6 and 195 mm long hollow fiber membranes t
As shown in (b), it was wound into a bundle by winding with gauze G, and the hollow fiber bundles T were filled into a washing basket 70 shown in FIG. The two washing baskets 70 were set on the rotary table 40 so as to face each other in order to balance the rotation.

Washing conditions were such that hot water at 90 ° C. was sprayed at an injection speed of 250 liters / minute for each washing, and washing was performed for 20 minutes while rotating the rotary table 40 at 20 rpm. Fresh water replenishment was performed at 15 liters / minute. The first spin-drying condition is as follows.
Drained for minutes. In the second dehydration, the rotary table 40 is rotated at 200 rpm, and the cooling water is injected for 5 minutes.
The liquid was drained for 5 minutes.

The residual solvent content of the hollow fiber membrane t thus obtained was 0.5 ppm or less, which is the gas chromatography detection limit. The solvent after heating 1.5 g of the hollow fiber membrane t in 150 cc of hot water at 70 ° C. for 1 hour has a wavelength of 22 μm.
UV absorption at 0 to 350 nm was 0.1 or less. The washing time by the above washing operation is 1 hour 4 in total.
It was 0 minutes, and the solvent in the hollow fiber membrane t could be removed in a short time.

Example 2 As in Example 1, the outer diameter was 460 μm and the inner diameter was 300 μm.
FIG. 6 shows a hollow fiber membrane t4600 having a length of 290 mm and a length of 290 mm.
The bundle was protected by the gauze G of (b), and the washing basket 70 was filled with 50 bundles in 5 rows and 10 stages. And Example 1
Similarly, two cleaning baskets 70 are set on the rotary table 40.

Washing conditions were such that hot water at 75 ° C. was sprayed at 250 liters / minute for each washing,
Washed for 15 minutes while rotating at rpm. 1 fresh water supply
Performed at 5 liters / minute. As for the dehydration conditions, the first dehydration was performed by draining the rotary table 40 at 250 rpm for 15 minutes. In the second dehydration, the rotary table 40 was rotated at 250 rpm, and after cooling water was injected for 3 minutes, the liquid was drained for 12 minutes.

The amount of the residual solvent in the hollow fiber membrane t obtained as described above was determined in the same manner as in Example 1 to a gas chromatography detection limit of 0.1.
It was 5 ppm or less. The UV absorption was 0.1 or less. The washing time by the above washing operation was 1 hour and 15 minutes in total, and the solvent could be removed in a short time as in Example 1.

(Comparative Example 1) The hollow fiber membrane t was filled in a washing basket 70 in the same manner as in Example 1,
It was immersed in an immersion tank. The wash water was heated to 95 ° C. and the wash water was replaced eight times. In addition, centrifugal dehydration was performed in order to enhance the washing effect, thereby increasing the effect of replacing the liquid. Fresh water replenishment was performed at 5 liters / minute.

As in Example 1, the amount of residual solvent in the obtained hollow fiber membrane t was 0.5 ppm or less for gas chromatography and the UV absorption was 0.1 or less, but the total processing time was 12 hours. Spent as long as hours.

Example 3 As in Example 1, the outer diameter was 280 μm and the inner diameter was 200 μm.
m, 1300 hollow fiber membranes having a length of 250 mm were protected by gauze G in FIG.
The washing basket 70 was filled with 40 bundles of the steps. As in the first embodiment, two cleaning baskets 70 are set on the turntable 40.

Washing conditions were such that hot water at 85 ° C. was sprayed at 250 liters / minute for each washing,
Washed for 15 minutes while rotating at rpm. 1 fresh water supply
Performed at 0 liter / min. As for the dehydration conditions, the first dehydration was performed by draining the rotary table 40 at 180 rpm for 15 minutes. In the second dehydration, the rotary table 40 was rotated at 180 rpm, and after cooling water was injected for 3 minutes, the liquid was drained for 12 minutes.

The amount of the residual solvent in the hollow fiber membrane t thus obtained was the same as the gas chromatography detection limit of 0.5 in Example 1.
ppm or less.

Comparative Example 2 For comparison, when the amount of the residual solvent was measured without washing the hollow fiber membrane t of Example 3, it was 150 ppm, and it was found that the desired washing effect of the present invention could not be obtained. Was.

[0048]

As is clear from the above description, according to the present invention, the washing basket in which the hollow fiber membrane is housed is rotated, and the washing water is sprayed from the surroundings to the washing basket, whereby the inside of the washing basket is removed. Cleaning water is forcibly supplied to the hollow fiber membrane of the above, and further, centrifugal force due to the rotation of the cleaning basket acts,
The solvent inside the hollow fiber membrane is forcibly discharged together with the washing water. As described above, the supply and discharge of the cleaning water are performed instantaneously and continuously, so that the processing time required for cleaning is reduced, and the cleaning water injected to the rotation center is centrifugally applied to the inside of the cleaning basket. Since water is passed through the entire surface, the washing water can be uniformly washed without stagnating inside the hollow fiber membrane.

Further, since the washing water is intensively injected into the hollow fiber membrane, the washing water can be efficiently used in a small space, and the cost required for washing can be reduced.

Further, when the supply of the washing water to the rotating washing basket is stopped, the hollow fiber membrane in the basket is dehydrated, so that the work of transferring the hollow fiber membrane from the washing step to the dehydrating step is performed. The process can be omitted, the number of personnel can be reduced, and cleaning with high working efficiency can be performed.

[Brief description of the drawings]

FIG. 1 is a horizontal sectional view of an embodiment of a hollow fiber membrane cleaning apparatus according to the present invention.

FIG. 2 is a sectional view taken along line GG in FIG.

FIG. 3 is a plan view of the turntable.

FIG. 4 is a sectional view taken along the line HH in FIG. 3;

FIG. 5 is a perspective view showing a cleaning basket.

FIG. 6 is a view showing a setting state of a hollow fiber membrane in a cleaning basket.

FIG. 7 is a view showing a setting state of a hollow fiber membrane in a washing basket.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Body 20 ... Cleaning water tank 30 ... Turntable 40 ... Rotary table 50 ... Injecting means 60 ... Cooling means 70 ... Cleaning basket t ... Hollow fiber membrane T ... Hollow fiber bundle G ... Gauze

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-4-241112 (JP, A) JP-A-5-156512 (JP, A) JP-A-52-121520 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) D01D 5/24 D01F 6/76 B01D 39/16 B01D 71/00-71/82

Claims (3)

(57) [Claims] 1. A washing water can pass through a spun hollow fiber membrane.
Stored in a bundle in a functional washing basket, and
Injecting washing water from the surroundings into the washing basket while washing
A method for producing a hollow fiber membrane, comprising purifying the hollow fiber membrane. 2. A process according to claim 1, wherein the hollow fiber membrane production method of the hollow fiber membrane, which is a polysulfone. 3. A manufacturing how <br/> method according to claim 1 or claim 2, wherein the hollow fiber membrane had an outer diameter of 100~800μ
m, wall thickness 5 to 150 μm and average pore size 0.001
A method for producing a hollow fiber membrane, characterized in that the thickness is from 5 to 5 μm.