JPH09253458A - Method for packing ion exchange material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of spaces which can make a short cut from the inlet to the outlet of a container and to enable high packing density of an ion exchange material by mechanically restricting the dimensional variation associated with the volume expansion of a filler in service environment by a container wall. SOLUTION: A dried filler 13 is placed in a rectangular parallelpiped metal container 11, a metal plate 12 is put on the container 11, and the position of a load cell 14 is set up so that the tip of the load cell 14 contacts the metal plate 12 when the filler 13 expands to have a thickness of 8mm. In other words, when the filler 13 is dried, the sum of the gap (a) between the tip of the load cell 14 and the metal plate 12 and the thickness (b) of the filler 13 is 8mm. Next, water is injected from water inlet 5, and when the shrinkage of water come to equilibrium, the pressure between the filler 13 and the metal plate 12 is obtained from the load on the load cell 14. Next, a volume ratio of a service state to a free state is obtained. From the results, an appropriate pressure in the container is selected.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for filling an ion exchanger. In particular, the present invention relates to a method for arranging an ion exchanger in a desalting chamber of an electrodialysis tank to continuously perform deionization, or a method for filling the ion exchange column with the ion exchanger.

[0002]

2. Description of the Related Art Conventionally, as an apparatus for producing ultrapure water, an electrodialysis tank characterized by having an ion exchanger in a diluting chamber has been disclosed in Japanese Examined Patent Publication No. 4-72567 and US Pat.
No. 745 and the like. These filled ion exchangers are required to be uniformly filled in each room and to not create a space where the liquid flow short-passes. However, it is generally difficult to uniformly and uniformly fill the plurality of dilution chambers in the electrodialysis tank with the ion exchanger.

For example, an electrodialysis tank for producing ultrapure water (ED
As a method for filling the bead-shaped ion exchanger used in I) into each dilution chamber, a method of filling each pair before or during assembly of the battery case, and a common duct for supplying liquid after assembly or filling of the ion exchanger A method of filling from a dedicated nozzle or the like is generally known.

However, in the method of filling each pair, there are problems that the structure of the chamber frame is complicated due to unitization and that it takes time to assemble when the number of pairs of battery cases is large.
On the other hand, in the method of filling from a common duct or a dedicated nozzle for filling the ion exchanger, the supply time to each room is shortened, but not only the structure of the chamber frame becomes complicated, but also the ion exchanger to each room is filled. There is a problem that it is difficult to control the filling degree and the confirmation of the filling amount is difficult.

Furthermore, since the upper limit of the amount of ion exchanger that can be filled is no more than the usual close packing (porosity = 0.636) or less, a downward flow is selected in order to prevent a short path of liquid. I have to do it. For this reason, it is necessary to take measures to remove gas in the dilution chamber system and to take measures to retain the liquid when the system is stopped.

[0006]

DISCLOSURE OF THE INVENTION The present invention prevents the generation of a space that may cause a short path from the inlet to the outlet of a container, and reliably stores a uniform amount of ion exchangers in a plurality of hollow portions at the same time. The purpose of the present invention is to achieve high packing density of the ion exchanger.

[0007]

DISCLOSURE OF THE INVENTION According to the present invention, a packing material containing an ion exchanger is housed in a container in a state in which the apparent volume of the packing material is smaller than that in the usage state, and the packing material is expanded in volume in a usage environment. Provided is a method for filling an ion exchanger which increases the pressure generated between the filling material and the container wall by mechanically limiting the accompanying dimensional change by the container wall.

The filler is a material which is placed in a container and exhibits an ion exchange action with the liquid in the container. The filler is not limited to the ion exchanger alone, and may include materials other than the ion exchanger. The filler may be an aggregate of materials separated from each other or a molded body. The aggregate of materials separated from each other refers to, for example, an aggregate of particles of the ion exchange resin, and each material includes not only granular materials but also fibrous or relatively large block-shaped materials. The molded body refers to one formed of a continuous material.

In the present invention, the filling material changes its state and is filled in the container. Hereinafter, in this specification, the state of the filler will be described with the following terms. The "usage state" is a state when the filler is actually used in the container, and is a state in which it is in equilibrium with the environment at the time of use. The "shrinking state" is a state in which the apparent volume of the filler is shrunk by some method. "Free state" means a state in which the environment of use is in equilibrium, but there is no constraint by the container wall.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION When the filler is an aggregate, the shape of each material is not particularly limited, but a spherical shape, a pellet shape, a fiber shape, a plate shape, a sheet shape, or the like can be adopted. These shapes may be used alone or in combination of two or more. The size is also not particularly limited, and various sizes can be adopted.

When the filling material is a molded body, it can contribute not only to the prevention of short path formation in the liquid flow direction of the liquid but also to the simplification of the apparatus assembling means, which is preferable. It is preferable that the molded body be formed by binding and molding the ion-exchanger particles into a porous state using a binder. As the ion exchanger particles, the same ones as when the filler is an aggregate can be used, and the spherical or pelletized ion exchanger is particularly preferable.

The amount of the binder used is 0.
It is desirable that the amount is 1 to 20% by weight, and particularly 1 to 5% by weight, for the reason of improving processability and handleability. As the binder, various organic polymer compounds can be preferably used. In particular, it is preferable to use a polyolefin type, preferably a polyethylene type or a polypropylene type, because the temperature at the time of kneading with the ion exchanger can be set to 150 ° C. or lower and the mechanical strength is improved.

As the ion exchanger, various organic ion exchangers or inorganic ion exchangers can be used alone or in admixture of two or more. Examples of the organic ion exchanger include ion exchange resins obtained by introducing an ion exchange group into an organic polymer such as a styrene-divinylbenzene copolymer and an acrylate polymer. Zeolite is mentioned as an inorganic ion exchanger.

The method of bringing the filler into the "shrinking state" must be selected according to the characteristics of the filler. When a normal ion exchange resin is used as the ion exchanger, the ion exchange resin has a large water content. Since the volume increases accordingly, it is preferable to bring the "contracted state" by reducing the water content. It is preferable to reduce the volume by shrinking the water content of the filler by 1% by weight or more, particularly 10% by weight or more. This includes not only the case of dehydration from the "use state" or "free state" in advance to the "shrink state", but also the case of obtaining a water content lower than that of the "use state" during the production. If the volume changes, the physical properties other than the water content, such as temperature, can be controlled to bring the material into a "contracted state".

As a means for reducing the water content, that is, for drying, heat drying is preferable. When an ion exchange resin is used as the ion exchanger, a temperature of 120 ° C. or lower, particularly 95 ° C. or lower, and further 30 to 6 to prevent deterioration.
It is preferable to heat-dry in the range of 0 ° C. For the reason that the time is further shortened or the change in water content is increased, a method of drying under reduced pressure under atmospheric pressure can be used. Also,
Similarly, as a method of reducing the water content of the ion exchanger,
A method of changing the concentration, composition, and type of the liquid around the packing material and a method of changing the counter ion of the ion exchanger can also be used.

After the filling material is stored in the container, it is gradually expanded when it is immersed in a liquid, for example, to be in a "used state".
In the present invention, since the expansion of the filler is limited by the container wall, the volume of the “use state” is smaller than that of the “free state”. This creates pressure between the filler and the container wall.

The pressure generated between the filler and the container wall is
It is preferably 0.1 kgw / cm ² or more. Pressure is 0.1k
When it is less than gw / cm ² , the effect of the present invention is not sufficiently exhibited, a short path is formed in the gap between the filler and the container wall, and the fluid to be treated flows therethrough, and the ion exchange capacity of the filler is reduced. It is not preferable because it may not be effectively expressed.
It is particularly preferable when the pressure is 0.5 kgw / cm ² or more. The greater the pressure, the greater the effect of suppressing the short pass, but in practice due to the strength of the container and the strength of the filler itself, it is 20 kgw / cm ² or less, especially 10 kgw /
cm ² or less is preferred. When the container wall has a relatively low strength such as an ion exchange membrane, it is preferably about 0.1 to 3 kgw / cm ^{2 in} order to prevent damage to the ion exchange membrane.

The pressure generated between the filler and the container wall is
It is determined by the difference in the size of the filler in the “free state” and the “used state” and the elastic property of the filler. When an ion exchange resin is used as the ion exchanger, the volume in the “used state” is preferably 30 to 97% based on the volume in the “free state”. A particularly preferred range is 50 to 95%.

When the volume of the filler in the "contracted state" is 30 to 99% based on the volume in the "used state", the pressure in the container generated when the volume is expanded is controlled with a certain degree of accuracy. It is desirable because it can be done. A more preferable range is 50 to 95%.

The volume of the filler in the "contracted state" is preferably 20 to 95% based on the volume in the "free state". A more preferable range is 40 to 90%. When expanding from "contracted state" to "free state" isotropically, the size of the filler in "contracted state" is "free state"
50 to 98% is preferable based on the dimension of. A more preferable range is 70 to 97%.

The filling material must be water permeable when stored in the container. Water permeability is preferably 100 kg
It is preferably at least cm · kgw ⁻¹ · h ⁻¹ . 1
If it is smaller than 00 kg · cm · kgw ⁻¹ · h ⁻¹ , the flow passage resistance when the filler is placed in the flow passage becomes large and the treatment amount decreases, or a high pressure is required for operation. Therefore, it is not preferable. Water permeability is 500 kg / cm
-It is particularly preferable if it is not less than kgw ^-1 · h ^-1 .

For the water permeability, a sample of a columnar body (for example, a prism or a cylinder) having two bottom surfaces parallel to each other is prepared, and water is prevented from leaking from the side surface, and P (kgw / cm ^{2) is applied} from one bottom surface. Water is introduced at a pressure of), and the mass of water flowing out from the other bottom surface is measured and obtained. At this time, the area of the bottom surface is A (cm ² ), the height of the columnar body, that is, the distance between the bottom surfaces is L (cm), and the amount of permeated water per hour is W
(Kg / h), the water permeability is WL / PA (kg
-Cm * kgw- ¹ * h- ¹ ). A, L, and P can be set arbitrarily, but A is about 1 to 1000 cm ² and L is 1
˜100 cm, and P is preferably 0.1 to 1 kgw / cm ² .

The porosity of the "used" filler is 1-40.
Volume% is preferable, and in order to avoid a short path in the liquid flow direction in the container for efficient ion exchange and to reduce the pressure loss in the container, 5 to 30% by volume is preferable.

When an ion exchange resin is used as the ion exchanger, if the packing density in the container is 0.2 to 2.0 g dry resin / cm ³ , short paths in the liquid flow direction in the container are avoided. Therefore, it is possible to efficiently perform ion exchange and to reduce the pressure loss in the container, which is preferable. It is further preferable that the packing density of the ion exchange resin is 0.5 to 1.5 g dry resin / cm ³ .

When the filler is a molded product, various shapes such as a tower type, a tube type, a disc type, a flat plate type, a box type and a spherical type can be used depending on the shape of the container. When the shape of the filler is similar to or close to the shape of the container, the pressure generated between the filler and each part of the container wall can be made uniform. For example, in a rectangular parallelepiped-shaped container, the ion exchanger is also a rectangular parallelepiped, and the length of each side is the same as the ratio of the length of each side of the rectangular parallelepiped-shaped container. They are equal, and the deformation of the filler is also isotropic. If the shape is significantly different from that of the container, there is a disadvantage that the strain inside the ion exchanger becomes large and the pressure generated at each part is not uniform. However, the strength of the container
It is also possible to intentionally use variants to control the pressure generated at the container wall. The same applies when the expansion of the ion exchanger itself is anisotropic.

When the filler is a molded product, it is preferable to dispose one continuous filler in the container in order to prevent short pass, but it may be appropriately divided and disposed. Also, it is not necessary for the filler to be uniform throughout, for example,
A portion containing only an anion exchanger as an ion exchanger,
The portion containing only the cation exchanger as the ion exchanger,
It may be arranged in a mosaic pattern. A porous body containing only anion exchange groups and a filler containing only cation exchange groups may be appropriately divided and arranged.

The shape of the container is, for example, a tower, a tube, a disk,
Various things such as boxes and balls can be adopted. These containers are
It may be a single type, or a part of which may be shared by a communicating pipe or a common duct. The container wall may be a selective diaphragm such as an ion exchange membrane.

The container used in the present invention is preferably a device that allows a liquid to flow therethrough and desorbs ions therein, that is, a desalting device. A diluting chamber of an electrodialysis device using an ion exchange membrane can be adopted as the container. Specifically, as an electrodialysis device, an electrodialysis tank configured by alternately arranging a plurality of cation exchange membranes and anion exchange membranes between an anode chamber having an anode and a cathode chamber having a cathode. Inside, there is a dilution chamber in which the anode side is partitioned by an anion exchange membrane, the cathode side is partitioned by a cation exchange membrane, and a concentration chamber in which the cathode side is partitioned by an anion exchange membrane and the anode side is partitioned by a cation exchange membrane. The form formed alternately can be illustrated.

The container must not be easily deformed in order to suppress the expansion of the filler and generate a pressure. When the container wall is made of an ion exchange membrane, it is difficult to give sufficient rigidity and strength to itself. Therefore, for example, when the packing material is placed in the dilution chamber, sufficient pressure is generated from the concentration chamber side. Therefore, it is necessary to take measures such as filling the concentrating chamber with a water-permeable material that does not substantially deform.

[0030]

【Example】

[Manufacture of Filler] A spherical cation exchange resin having an average diameter of 500 μm (manufactured by Mitsubishi Chemical, trade name Diaion SK1B) and a spherical anion exchange resin having an average diameter of 500 μm (manufactured by Mitsubishi Chemical, trade name Diaion SA10A) are used in a volume ratio. Fifty
The mixture was mixed at / 50 and dried at 50 ° C. The weight was reduced to 55% by weight of the original weight by drying. Pelletized polyolefin resin (polyolefin plastomer) with a diameter of 2 to 6 mm and a length of 4 to 9 mm as a binder
To the total amount of the binder and the ion exchange resin so that the amount of the binder is the amount shown in Table 1 and 1 with a kneader.
Kneading was carried out at 40 ° C. for 40 minutes. This kneaded product has an opening surface of 25
Place in a 0 mm x 150 mm rectangular parallelepiped metal mold, and
A rectangular parallelepiped porous molded body was obtained by pressing at 0 ° C. × 25 kgw / cm ² .

At this time, by changing the amount filled in the mold, molded products having thicknesses of 6.7 mm, 7 mm and 7.5 mm, respectively, were obtained from the kneaded products of each mixing ratio, as shown in Table 1. The width and the length of the molded body are such that the ratio of length: width: thickness is 14
Cut according to the thickness so that it becomes 0: 100: 8,
Fillers 1-9 were obtained. When these fillers were immersed in pure water for 8 hours at room temperature, they expanded in the length, width, and thickness directions at almost the same rate, and reached equilibrium. The amount of increase in length with respect to the original length is shown in Table 1 as a coefficient of expansion.

[0032]

[Table 1]

[Measurement of Expansion Pressure] A rectangular parallelepiped metal container 11 (bottom width 100 mm, bottom length 140) as shown in FIG.
mm), and put the filler 13 in the dry state (this 13 is the symbol in FIG. 1), put the metal plate 12 on it, and let the filler 13 expand to a thickness of 8 mm. The position of the load cell is set so that the tip of the load cell 14 comes into contact with the metal plate 12 when it reaches the limit. That is, when the filler 13 is in a dry state, the sum of the gap a between the tip of the load cell 14 and the metal plate 12 and the thickness b of the filler 13 is set to 8 mm. Next, water was injected from the water injection port 5, and the pressure between the filler 13 and the metal plate 12 was obtained from the load applied to the load cell 14 when the water absorption was in equilibrium. Next, the volume ratio of the used state to the free state = (used state volume / free state volume) × 100% was obtained. Table 2 shows the results. Using this result, it is possible to select an appropriate in-container pressure by adjusting the size in the length, width, and thickness directions.

[0034]

[Table 2]

[Evaluation by electrodialysis] Fillers 1 to 9 were
It was put in the diluting chamber 27 of the electrodialysis tank having the configuration shown in FIG. 2 and tightened to a specified size. The shape of the diluting chamber 27 is a rectangular parallelepiped, the length in the water flow direction is 140 mm, the width is 100 mm, and the space between the anion and cation exchange membranes is 8 mm. Each of the two concentrating chambers 26 was filled with a polypropylene spacer net so that the spacing between the anion and cation exchange membranes did not substantially change even when the filler in the diluting chamber 27 expanded.
Therefore, even in this dilution chamber, the respective fillers generate the same pressure as shown in Table 2. In addition, as a filler 10 for comparison, the amount of the binder prepared in the same manner as the fillers 1 to 9 is 2% by weight, and 111 mm × 79.4 mm × 6.3 m.
The molded body of m was filled with water having a size the same as that of the dilution chamber 27 by sufficiently absorbing water.

Then, the conductivity of the dilution chamber is about 10 μS / c.
m of pure water is 0.18 liter / h, water of which conductivity is about 1 mS / cm is 20 liter / h in the concentrating chamber, and water of which conductivity is about 200 μS / cm is 1 liter / h in the anode chamber and the cathode chamber.
A current of 1.0 A was applied under the same conditions while flowing each h for 1 hour. When it was operated continuously for 40 hours and became stable, the flow rate in the diluting chamber was set to 28.8 liter / h, and the pressure loss at the upper and lower ends of the diluting chamber of the electrodialysis tank,
The electric conductivity of the deionized water discharged from the dilution chamber and the specific resistance of the dilution chamber were measured. The results are shown in Table 3.

[0037]

[Table 3]

With the fillers 1 to 9, high-purity deionized water could be stably obtained, and the electric resistance was low. Further, as shown in FIG. 2, the higher the pressure of the filler, the better the characteristics tend to be. On the other hand, in the filler 10, the purity of the dilution water was not high. From the measurement of the pressure loss, it is considered that a gap was generated between the ion exchanger and the chamber frame or between the ion exchanger and the ion exchange membrane from the inlet to the outlet of the dilution chamber.

Since it is considered that the fillers 1 to 9 have substantially no short path, the water permeability of the filler is calculated from the above pressure loss as shown in Table 4. Similarly, when the water permeability of the filler 10 is calculated, the value is remarkably high, but this is not the value of the water permeability of the filler because a large amount of water is flowing through the short path.

[0040]

[Table 4]

[0041]

According to the filling method of the present invention, it is possible to prevent the generation of a space in which the water supplied from the inlet to the outlet of the container may short-pass, and to ensure a uniform amount of ion exchangers in a plurality of hollow portions at the same time. It can be stored, the packing density of the ion exchanger can be increased, and the ion exchanger can be packed in a short time.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a method for measuring a pressure between a filler and a container wall.

FIG. 2 is an explanatory diagram showing the configuration of the electrodialysis tank used in the examples.

[Explanation of symbols]

 11: Metal container 12: Metal plate 13: Filler 14: Load cell 15: Water inlet 21: Cathode 22: Anode 23: Cathode chamber 24: Anode chamber 25: Cation exchange membrane 26: Concentration chamber 27: Dilution chamber 28: Anion exchange membrane

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Ken Komatsu, 1150 Hazawa-machi, Kanagawa-ku, Yokohama, Kanagawa Prefecture Central Research Institute, Asahi Glass Co., Ltd. (72) Inventor Ichiro Terada, 1150, Hazawa-machi, Kanagawa-ku, Yokohama, Asahi Glass Co., Ltd Central Research Center

Claims (10)

[Claims] 1. A packing material containing an ion exchanger is housed in a container in a state in which the apparent volume of the packing material is contracted from that in the usage state, and a dimensional change caused by volume expansion of the packing material in a usage environment is mechanically controlled by a container wall. Method for filling an ion exchanger in which the pressure generated between the packing material and the container wall is increased by restricting it mechanically. 2. The method for packing an ion exchanger according to claim 1, wherein the packing material containing the ion exchanger is an aggregate of materials separated from each other. 3. The method for filling an ion exchanger according to claim 1, wherein the filler containing the ion exchanger is a molded body. 4. The method for filling an ion exchanger according to claim 3, wherein the molded body is obtained by molding the ion exchanger particles into a porous form with a resin binder. 5. The method for filling an ion exchanger according to claim 1, wherein the container is a desalting device. 6. A container is disposed between the anode and the cathode,
The method for filling an ion exchanger according to claim 5, wherein the container is defined by an anion exchange membrane on the anode side and a cation exchange membrane on the cathode side. 7. The method of volume contraction is drying.
6 Any one of the methods for filling an ion exchanger. 8. The pressure generated between the filler and the container wall is
It is 0.1-20 kgw / cm < ² >, The filling method of the ion exchanger of any one of Claims 1-7. 9. The method for filling an ion exchanger according to claim 1, wherein the volume of the filler at the time of use is 30 to 97% of the volume when the volume is freely expanded. 10. The porosity of the filler in a volume expanded state is 1 to 40% by volume.
The method for filling the ion exchanger of.