JPH0626348Y2 - Ion exchange tower - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an ion exchange tower using ion exchange fibers,
More specifically, it relates to a novel ion exchange column capable of performing extremely excellent filtration treatment simultaneously with ion exchange treatment.

<Prior art> Conventionally, an ion exchange filled with a granular ion exchange resin for the purpose of removing impurity ions in the stock solution or concentrating and purifying a trace amount of valuables ions in the stock solution. The tower is widely used. In the ion exchange tower, of course, the ion exchange treatment is performed, but at the same time, the suspension (S
It is also possible to remove S). However, the particle size of ion exchange resins is generally as small as 0.2 to 0.6 mm, so SS
When the undiluted solution containing is directly passed through the ion exchange resin layer, the ion exchange resin layer is frequently clogged. Therefore, it is necessary to introduce washing water and washing air into the tower from the lower part of the ion-exchange tower to carry out backwashing and washing of the ion-exchange resin layer, and to continue the passage unless the clogging is eliminated. .

However, if the ion exchange resin layer is backwashed during the passage, the quality of the treatment liquid obtained when the passage is restarted after the backwash causes a problem that the quality becomes significantly worse than that before the backwash. . This is because, if the passage to the ion exchange column is stopped halfway, the target ions in the stock solution to be removed, such as impurity ions, have already been adsorbed in the column and the ion exchange capacity has already been lost. A layer of ion exchange resin that does not have and has not yet adsorbed impurity ions,
In other words, there is a layer of ion-exchange resin having activity, a layer of ion-exchange resin having no activity on the inflow side of the stock solution of the ion-exchange tower, and an ion-exchange resin having activity on the outflow side of the treatment solution of the ion-exchange tower. Although the resin layer is located, backwashing the ion-exchange resin layer completely mixes the inactive ion-exchange resin with the inactive ion-exchange resin and activates the ion-exchange tower on the treated solution outlet side. When there is an ion exchange resin that does not have such impurities, the impurity ions adsorbed on the ion exchange resin that does not have the activity are desorbed and leaked into the treatment liquid when the passage is restarted after backwashing. The quality of the liquid deteriorates.

Further, since the specific gravity of the ion exchange resin is extremely low, there is a problem that the ion exchange resin will flow out from the inside of the tower during the washing if the flow rate of the washing water is too high. Therefore, there is a drawback that the cleaning becomes insufficient.

As described above, the ion exchange resin layer has a relatively small filtration capacity, and it is generally not preferable to carry out backwashing during the ion exchange treatment. A method is generally employed in which various filtration devices are installed in front of the exchange tower, SS in the stock solution is removed in advance by the filtration device, and then treated in the ion exchange tower.

<Problems to be solved by the device> However, even if sufficient filtration can be performed in the ion exchange column and backwashing is performed during the passage of the liquid, the liquid can be re-passed without any problem thereafter. If it is possible, it is not necessary to install a filtration device in the preceding stage of the ion exchange column, and therefore the equipment is extremely inexpensive and
The processing system becomes simple.

The present invention was made under such a background,
It is an object of the present invention to provide an ion exchange column having both an ion exchange function and a filtration function and capable of performing extremely excellent filtration treatment.

<Means for Solving Problems> The ion exchange tower of the present invention made to achieve the above object has a support attached inside the tower, and a long fiber which is an ion exchange fiber above the support. While fixing the lower end of the column, a large number of ion-exchange long fibers are erected all over the tower with the upper end being a free end, and the stock solution is passed in a descending flow from the upper end to the lower end of the ion-exchange long fibers. It is characterized by being configured.

Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic cross-sectional view showing an example of an embodiment of the present invention, in which a support 2 made of a perforated plate is horizontally provided in the lower part of a tower 1, and the support 2 is a long ion exchange fiber. The lower end of the fiber 3 is fixed, and the upper end of the ion-exchange long fiber 3 is set as a free end, and a large number of ion-exchange long fibers 3 are erected in the entire tower 1. Further, the stock solution inflow pipe 4 is connected to the upper part of the tower 1, and the backwash water outflow pipe 5 is branched and connected to the stock solution inflow pipe 4.

Further, a treatment liquid outflow pipe 6 is connected to the lower part of the tower 1, and a backwash water inflow pipe 7, an air inflow pipe 8 and a regenerant inflow pipe 9 are branched and connected to the treatment liquid outflow pipe 6. In addition, 10, 11,
Reference numerals 12, 13, 14, and 15 denote valves, respectively.

Explaining the ion-exchange long fibers 3 used in the present invention, for example, there are known ion-exchange fibers obtained by introducing ion-exchange groups into synthetic fiber materials such as polyacrylic, polyamide, polystyrene, and polyvinyl alcohol.
For example, a single fiber having a length of 1,000 mm to 5,000 mm or a bundle of the single fiber is used. The types of ion exchange fibers include cation exchange fibers having cation exchange groups such as sulfonic acid groups and carboxyl groups, anion exchange fibers having anion exchange groups such as primary to tertiary amino groups and quaternary ammonium groups. And chelate fibers having a chelate group such as an amidoxime group, an imidodioxime group, and a dithiocarbamic acid group.

The thickness of the ion exchange fiber is, for example, 10
Known materials having a thickness of up to 60 μm can be used.

It should be noted that the filling amount of the ion-exchange long fibers 3 is such that even if the undiluted solution having a relatively high flow rate is passed through in a downward flow, the long fibers 3 are slightly bent and the height thereof is slightly contracted. It is desirable that the filling amount is such that the liquid stream does not bend horizontally and the column 1 is entirely upright. With such a filling amount, it is possible to form a filling layer having an extremely large porosity and suitable for filtration.

<Operation> When the undiluted solution containing SS is treated in the ion exchange tower of the present invention, the following operation is performed after the ion exchange long fibers 3 standing in the tower 1 are regenerated into a predetermined ion form in advance. .

That is, the valves 10 and 14 are opened, and the stock solution inflow pipe 4 is opened.
A stock solution containing SS flows in in a downward flow.

As described above, the ion-exchange long fibers 3 are produced by the flow of the stock solution.
Although the fiber is bent slightly and the height thereof is slightly contracted, the continuous fiber 3 is entirely upright in the tower 1, so that the undiluted solution descends from the upper end to the lower end of the ion exchange continuous fiber 3 which is upright. In the meantime, the target ions to be removed in the stock solution are adsorbed to the ion-exchange long fibers 3 by the ion exchange reaction, and at the same time, the SS in the stock solution are captured in the voids of the long fibers 3 and the target ions and SS The processing liquid from which the and are removed flows out from the processing liquid outflow pipe 6.

Further, since the ion-exchange long fibers 3 are slightly bent due to the downward flow, the ion-exchange long fibers 3 are packed more closely than the non-bent vertical long fibers, and as a result, the stock solution does not short-pass through the long fiber layer, and therefore SS Can be effectively captured by the packed layer of the long fibers 3.

By continuing the liquid passing, SS in the voids of the ion-exchange long fibers 3
Is captured, and the pressure loss gradually increases. In addition, as the pressure increases, the degree of bending of the ion-exchange long fibers 3 increases, and the height of the long fibers 3 standing upright gradually decreases.

By continuing such a passage, the pressure loss reaches a specified value or the filtration ability is lost even though the ion exchange ability of the ion exchange long fibers 3 is still sufficient, and the ion exchange long fibers 3 enter the treatment fluid. If there is a large amount of SS leaked out, stop the passage of the liquid and perform the following backwash.

That is, the valves 10 and 14 are closed, the valves 11 and 13 are opened, and the compressed air flows in from the air inflow pipe 8.

By the inflow of the compressed air, the liquid in the tower 1 is stirred and the ion exchange long fibers 3 vibrate, the voids formed between the fibers are destroyed, and the SS aggregates or SS aggregates are destroyed, Further, the SS and the agglomerates attached to the ion exchange long fibers 3 are peeled off.

Then, while continuing the inflow of the compressed air or closing the valve 13 to stop the inflow of the compressed air, the valve 11 is opened and the valve 12 is opened to allow the backwash water to flow from the backwash water inflow pipe 7.

At this time, since the lower end of the ion-exchange long fiber 3 is fixed to the support 2 and the upper end thereof is a free end,
As a result of the upward flow of the backwash water that has flowed in, the ion-exchange long fibers 3 expand like a windsock with the support 2 as a fixed portion as shown in FIG. 2, and each fiber vibrates.
Therefore, the SS cannot stay in the ion-exchange long fibers 3, the SS is separated from the long fibers 3, and the backwash drainage containing a large amount of the SS flows out from the backwash water outflow pipe 5.

In the ion exchange tower of the present invention, the ion exchange long fibers 3
Since the lower end of is fixed to the support 2, the long fiber 3 does not flow out of the tower 1 even if the backwash water at a high flow rate flows in. Therefore, compared with the conventional ion exchange column filled with ion exchange resin, it is possible to flow backwash water at a higher flow rate than that of the conventional ion exchange tower, and to remove SS efficiently in a shorter time than in the past. You can

When such backwashing is completed, the stock solution is caused to flow into the tower 1 through the stock solution inflow pipe 4, and the stock solution is treated again. At this time, in the apparatus of the present invention, a treatment liquid of the same quality as that before the backwash can be obtained. This is because, since the lower end of the ion-exchange long fiber 3 is fixed as described above, even if the above backwashing is performed, the activity is already lost due to the passage of liquid before the backwashing as in the case of the conventional ion-exchange resin. This is because the broken product and the active product are not mixed, and the packed bed having the same ion distribution as that before the backwash is maintained after the backwash.

When the ion exchange ability of the ion-exchange long fibers 3 is lost and the quality of the resulting treatment liquid deteriorates while continuing the above-mentioned liquid passage through backwashing, the ion-exchange long fibers 3 Are backwashed as described above to remove the trapped SS, and then regenerated by a conventional method. The regeneration may be carried out by so-called downflow regeneration in which a regenerant such as acid or alkali is introduced from the upper part of the tower 1 in the same manner as the stock solution and the ion exchange long fibers 3 are regenerated in a downflow, or the regenerant is used. Contrary to the undiluted solution, it may be carried out by so-called upflow regeneration in which it is introduced from the lower part of the tower 1 and is regenerated in an upflow, but either the regeneration efficiency is good or the quality of the treatment liquid obtained during the passage of liquid after regeneration Therefore, it is desirable to use the upflow regeneration.

FIG. 1 shows an example in which the ion exchange tower of the present invention is an upflow regeneration type, and regeneration in the ion exchange tower is performed as follows.

That is, after performing the above-mentioned backwash, the valves 12 and 13 are closed, the valve 15 is opened, and the regenerant having a predetermined concentration is flown into the column 1 through the regenerant inflow pipe 9 in an upward flow. While the regenerant that has flowed in rises in the packed bed of the ion-exchange long fibers 3, the target ions adsorbed on the ion-exchange long fibers 3 are desorbed by the regenerant, and the ion-exchange long fibers 3
Is played. After the completion of the regenerant passing step, so-called "extrusion step" and "washing step" are carried out to end the regeneration operation. These steps are the upward flow in the conventional ion exchange tower filled with ion exchange resin. Since it is similar to the case of reproduction, detailed description will be omitted.

Incidentally, in the case of a conventional upflow regeneration ion exchange column filled with an ion exchange resin, various means for preventing the ion exchange resin layer in the column from being pushed up and flowing by the upflow of the regenerant. However, in the case of the present invention, since the lower end of the ion-exchange long fiber 3 is fixed, the upflow regeneration can be performed without any problem without taking any special means.

FIG. 3 is a schematic cross-sectional view showing another embodiment of the present invention, showing the structure in the case where the cross-sectional area of the tower 1 is relatively large.

That is, when the cross-sectional area of the tower 1 becomes large, it becomes difficult to erect the ion-exchange long fibers 3 as a whole during the passage as shown in FIG. 1, and the ion-exchange long fibers 3 become horizontal during the passage. It tends to bend into a shape. If the ion-exchange long fibers 3 are bent horizontally during the passage of the liquid, the long fibers 3 will be densely packed and the pressure loss will be correspondingly large, which is not preferable.

Therefore, as shown in FIG.
6 may be erected and the inside of the tower 1 may be divided vertically by the dividing plate 16.

The partition plate 16 acts as a barrier plate that prevents the ion-exchange long fibers 3 from bending horizontally, and even if the ion-exchange tower has a large cross-sectional area, the ion-exchange long fibers 3 do not bend horizontally. Absent.

The operation of passing, backwashing, or regeneration is the same as in the ion exchange column shown in FIGS. 1 and 2.

In the ion exchange tower of the present invention, the higher the packing density of the ion exchange long fibers packed in the tower, the finer the SS.
Can be removed and a clearer processing solution can be obtained, but on the contrary, the pressure loss becomes large.

Further, as the packing density decreases, S in the processing liquid
Although the leakage amount of S is large and the processing liquid is deteriorated, the pressure loss is small on the contrary.

Therefore, the packing density should be the most suitable depending on the quality or quantity of SS in the stock solution, but usually unit volume (1 m ³ )
The packing density should be 10 to 100 kg (dry weight) per unit.

The ion exchange tower of the present invention can produce pure water, condensate treatment in thermal power plants and nuclear power plants, desalination or decolorization treatment of sugar solution, by variously selecting the type of ion exchange long fibers to be filled. It can be applied to all fields in which ordinary granular ion exchange resins are used, such as removal of harmful metals or separation and purification of useful metals.

For example, in the case of pure water production, which is the most general method for ion exchange treatment, a cation tower filled with cation exchange long fibers having sulfonic acid groups and an anion exchange long fibers having quaternary ammonium groups are filled. Pure water can be produced by combining with an anion exchange tower
Alternatively, an ion exchange tower may be used in which both ion-exchange long fibers are regenerated in advance and then mixed and erected in the same tower. When both ion-exchange long fibers are mixed in the same column, it is difficult to regenerate in the column even if the capacity of the ion-exchange long fibers is lost. To be disposable.

<Effect> As described above, the ion-exchange tower of the present invention uses the ion-exchange long fibers as the ion-exchanger to be filled inside, and a large number of the ion-exchange long fibers can be totally dispersed in the tower even during the passage of liquid. Since the stock solution is flowed in a downward flow from the upper end to the lower end of the standing long fibers, the pressure loss during liquid flow is small,
Therefore, the liquid can be passed at a high flow rate, and the suspension is effectively removed when the undiluted liquid passes through a large number of fibers, and a clear treatment liquid can be obtained.

In addition, since the ion-exchange long fibers have an extremely high reaction rate as compared with ordinary granular ion-exchange resins, it is possible to perform sufficient ion-exchange treatment even if the stock solution is passed at a high flow rate, and therefore, compared to conventional methods. The cross-sectional area of the ion exchange tower can be reduced, and the installation cost and installation area can be greatly reduced.

Further, in the ion exchange tower of the present invention, since the lower end of the ion exchange long fiber is fixed by the support, the ion exchange long fiber may be separated from the tower even if high-speed backwash water is passed through. Therefore, the backwashing step can be performed in a short time with the backwashing water having a high flow rate, and the suspension can be reliably discharged to the outside of the column by the backwashing step. Moreover, in the re-passage after the backwash, unlike the conventional ion exchange column using the ion exchange resin, there is no problem that the quality of the treatment liquid becomes worse than that before the backwash, which is the same as before the backwash. It is possible to obtain a high quality processing liquid.

Thus, using the ion exchange tower of the present invention, the ion exchange treatment and sufficient filtration treatment can be performed in one tower, and a filtration device is not required, further reducing installation cost and equipment area. The processing system can be simplified and the practical value is extremely large.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an ion exchange tower which is an example of an embodiment of the present invention, and FIG. 2 is a schematic sectional view showing a state of backwashing of the ion exchange tower shown in FIG. FIG. 3 is a schematic cross-sectional view of an ion exchange tower which is another embodiment of the present invention. 1 ... Tower, 2 ... Support 3 ... Ion-exchange long fibers, 4 ... Stock solution inlet pipe 5 ... Backwash water outlet pipe, 6 ... Treatment liquid outlet pipe 7 ... Backwash water inlet pipe, 8 ... … Air inflow pipe 9 …… Regenerant inflow pipe 10, 11, 12, 13, 14, 15 …… Valve 16 …… Dividing plate

Claims (1)

[Scope of utility model registration request] 1. A support is attached to the inside of a tower, the lower end of a long fiber which is an ion exchange fiber is fixed to the upper part of the support, and the upper end is a free end, and a large number of ion exchanges are carried out throughout the tower. An ion exchange tower, characterized in that long fibers are erected upright, and the stock solution is passed in a downward flow from the upper end to the lower end of the ion exchange long fibers.