JPH0799999A - Regeneration of mixed bed-type sucrose liquor purifier - Google Patents

Abstract

PURPOSE:To provide the subject regeneration method so designed that malregeneration due to incomplete separation can be obviated by added regeneration operation upon the strongly anion exchange resin, thereby preventing color component from its a accumulation and obtaining purified sucrose of stable purity for a long period of time. CONSTITUTION:In regenerating a mixed bed-type sucrose liquor purifier made up of a strongly basic anion exchange resin and a weakly acidic cation exchange resin, the latter resin is first regenerated and then both the resins are separated in layers using a saline solution followed by regenerating the former resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to the regeneration of a mixed bed type sucrose solution purifying apparatus using a strongly basic anion exchange resin and a weakly acidic cation exchange resin used in the desalting and decolorizing purification steps of sucrose solution. It is about law.

[0002]

2. Description of the Related Art In order to purify sucrose solution, it is known to use an ion exchange resin for decolorization and desalting.
As a conventional purification method, a so-called reverse method, which is a two-bed treatment method in which sucrose solution is passed through two beds of a strongly basic anion exchange resin bed and then a weakly acidic cation exchange resin bed for purification, has been adopted. It was However, this treatment method has a drawback that the desalination purity (electrical conductivity) of the treated sucrose solution is not improved so much. Therefore, in recent years, a mixed bed treatment method in which a purified sucrose solution having a high desalination purity is passed through a mixed bed of a strongly basic anion exchange resin and a weakly acidic cation exchange resin for purification is being widely used. .

However, in the mixed bed type, the volume change of the weakly acidic cation exchange resin before and after the passage of the sucrose liquid is extremely large, and the strong basic anion exchange resin in the liquid passing state and the liquid passing state are the same. Since the specific gravity is relatively close to that of the weakly acidic cation exchange resin in Fig. 3, separation regeneration of both ion exchange resins is incomplete during regeneration of the mixed bed, and regeneration failure is likely to occur. In order to prevent the adsorption and accumulation of dye components in the exchange resin, regeneration operation with acid, oxidant, etc. is indispensable, but in the mixed bed type, this regeneration operation requires an extremely complicated procedure, so avoid regeneration operation as much as possible. Therefore, there is a problem that the adsorption ability of the dye component gradually decreases.

[0004]

DISCLOSURE OF THE INVENTION The present invention eliminates a regeneration failure due to incomplete separation of a strongly basic anion exchange resin and a weakly acidic cation exchange resin in a mixed bed type sucrose liquid purifying apparatus, and a strong base. It is an object of the present invention to provide a regeneration method which prevents accumulation of a dye component in a cationic anion exchange resin and can always obtain a treated sucrose solution having a stable liquid quality.

The present invention achieves the above object, and the gist of the invention is to provide a mixed-bed sucrose solution filled with a strongly basic anion exchange resin and a weakly acidic cation exchange resin. In regenerating the purification device, the first step of contacting the hydrochloric acid solution with the mixed bed of the strongly basic anion exchange resin and the weakly acidic cation exchange resin, injecting saline from the bottom of this mixed bed to make it strongly basic. The second step of stratifying and separating the anion exchange resin layer and the weakly acidic cation exchange resin layer, the third step of bringing the caustic soda solution into contact with the strong basic anion exchange resin layer, and the strong basic anion exchange The present invention resides in a method for regenerating a mixed-bed sucrose solution purifying apparatus, which comprises sequentially performing a fourth step of mixing a resin layer and a weakly acidic cation exchange resin layer.

The method of the present invention will be described with reference to the attached FIG. FIG. 1 is a schematic vertical sectional view of an example of a mixed bed type sucrose solution purifying apparatus used for carrying out the present invention. In the figure, 1 is a resin tower, 2 is a strongly basic anion exchange resin and a weak one. Mixed bed composed of acidic cation exchange resin, 3 is a dispersion tube, 4 is a lower collecting tube, 5 is an intermediate collector, 6, 7, 8 and 9 are pipes, and 10 is a mixed bed subjected to stratification treatment. The location of the boundary surface between the two resin layers is shown.

First, the purification process of the sucrose solution prior to the regeneration will be described.
After being introduced into the resin tower 1 through the mixed bed 2 in a downward flow and impurities are removed therein, a refined sucrose solution is obtained as a processing solution through the lower liquid collecting pipe 4 and the pipe 9. . The sucrose solution is allowed to flow until the purity of the treated sucrose solution tends to deteriorate, or until a predetermined amount is processed. After the passage of the liquid, the sucrose solution remaining in the resin tower 1 is recovered, and then the mixed bed 2 is regenerated.

The regeneration treatment of this mixed bed 2 is characteristic of the present invention, but in order to clarify the difference from the conventional regeneration method, the conventional regeneration method will be described first. In the conventional method, backwash water such as demineralized water is introduced from the pipe 9 and the lower liquid collection pipe 4, and the upper layer is stratified and separated into the strongly basic anion exchange resin layer and the lower layer into the weakly acidic cation exchange resin layer. Next, a regenerant liquid such as hydrochloric acid is passed through the pipe 6 and the dispersion pipe 3, and the waste regenerated liquid is discharged from the lower liquid collection pipe 4 and the pipe 9 to regenerate the lower weakly acidic cation exchange resin layer.

Next, a regenerant such as caustic soda is passed through the pipe 6 and the dispersion pipe 3 in a downward flow, and the regenerated waste liquid is a boundary between the strongly basic anion exchange resin layer and the weakly acidic cation exchange resin layer. By discharging from the intermediate collector-5 installed in the vicinity of the surface contacting portion 10, the upper strong basic anion exchange resin layer is regenerated. When the passage of the regenerant is completed, washing water such as demineralized water is injected from the dispersion pipe 3 and the lower liquid collecting pipe 4 as necessary,
By discharging from the intermediate collector-5, both resins are mixed to form a mixed bed and used for the next purification of the sucrose solution.

In such a conventional method, since the specific gravities of the strongly basic anion exchange resin and the weakly acidic cation exchange resin are close to each other, it is difficult to perform good stratification, and therefore, the strong basic anion exchange resin is difficult to separate. When the resin is regenerated, the weakly acidic cation exchange resin is contaminated with caustic soda, and the desalination purity of the sucrose solution is not improved. Furthermore, unless a regeneration operation for desorbing the dye component adsorbed on the strongly basic anion exchange resin is added, the dye component may be accumulated and the dye component adsorbing ability may be gradually reduced.

On the other hand, in the method of the present invention, first, the hydrochloric acid solution is passed through the pipe 6 and the dispersion pipe 3 to bring the hydrochloric acid solution into contact with the mixed bed 2, and the waste waste liquid is discharged from the lower liquid collecting pipe 4 and the pipe 9. The first step of regenerating the weakly acidic cation exchange resin is performed. At that time, the hydrochloric acid solution was passed under the following conditions: concentration 3 to 8% by weight, space velocity (SV) 2 to 5 / hour, regeneration level 60 to 100 g (HCl) / 1000.
Using ml (cation exchange resin) as a guide, adjust and change according to the load condition of the weakly acidic cation exchange resin. Then, saline is injected from the pipe 9 and the lower liquid collecting pipe 4 in an upward flow, and the waste liquid is discharged from the dispersion pipe 3 and the pipe 7, whereby the mixed bed 2 is made to have a strong basic anion exchange resin layer and a weak acidity. A second step of stratifying and separating the cation exchange resin layer is performed.

The salt solution used in the second step is selected from the range of 10 to 20% by weight in which a regenerating operation is carried out as a large frame. Among them, one having a specific gravity satisfying the following conditions is used. That is, the specific gravity of each form of both ion exchange resins at the time of passing through the first step (specific gravity of the loaded form of the strongly basic anion exchange resin and that of the regenerated form of the weakly acidic cation exchange resin). The specific gravity between those) is adjusted to the specific gravity between them, and this is used to achieve complete stratification of both resins.

Injection of saline solution is carried out at a flow rate of both ion exchange resins of 5 to 8 m / hour for about 10 minutes until the layer separation of both resins is completed. Desorption of the dye component adsorbed on the ion-exchange resin, that is, regeneration operation is also performed at the same time, so the injection time may be appropriately extended depending on the contamination condition of the resin, or the temperature may be raised to about 50 to 80 ° C. You may inject it.

The strongly basic anion exchange resin is regenerated as a third step following the second step. The operation procedure is the same as that described in the conventional method, that is, caustic soot as a regenerant. -The Da solution is passed through the pipe 6 and the dispersion pipe 3 in a downward flow to regenerate the strongly basic anion exchange resin which is stratified and located in the upper layer, and then the waste liquid is discharged from the intermediate collector-5. .

The replenishing conditions of the caustic soda solution of the regenerant are concentration.
3-5% by weight, space velocity 2-6 / hour, playback level 80-100 g
The range is (NaOH) / 1000 ml (anion exchange resin). After the strong basic anion exchange resin is regenerated by passing through a caustic soda solution, demineralized water is introduced by an operation procedure similar to the above-mentioned conventional method to wash both resin layers with water, if necessary. Following this, a fourth step of bringing the anion and cation ion exchange resin layers which have been stratified and separated into a mixed bed state according to a conventional method is carried out, and when this is completed, the next step of purifying the sucrose solution is carried out.

[0016]

EXAMPLES Next, examples of the method of the present invention will be described, but the present invention is not limited by the following examples unless it exceeds the gist. Example 1 Diaion PA312 [manufactured by Mitsubishi Kasei Co., Ltd., Diaion is a registered trademark of Mitsubishi Kasei Co., Ltd.] 2000 ml which is a strongly basic anion exchange resin and Diaion WK11 [Mitsubishi Kasei Co., Ltd.] which is a weakly acidic cation exchange resin. 1000 ml is packed into a jacketed glass column with an inner diameter of 10 cm and a length of 100 cm to form a mixed bed.

To this mixed bed, 1200 ml of a 5 wt% hydrochloric acid aqueous solution was passed from the upper end of the column in a downward flow of space velocity 2.5 / hour (first
Process), and then 17% by weight (specific gravity 1.13) saline solution was injected from the bottom of the column at an upward flow rate of 7.5 m / h for 15 minutes to form a strong basic anion exchange resin layer and a weakly acidic cation exchange resin layer. The layer is separated into layers (second step). During injection of saline solution in this second step, strong basic anion exchange resin (Diaion PA3
12) is a load type (Cl type), and the specific gravity at that time is 1.08, while a weakly acidic cation exchange resin (Diaion WK11)
Is a regenerated type (H type), the specific gravity at that time is 1.16, and the specific gravity of the saline solution used is in the middle of the specific gravity of both resins as described above.

Following the second step, 3800 ml of a caustic soda aqueous solution having a concentration of 4% by weight was passed downward at a space velocity of 5 / hour from the upper end of the column, and the position was 13 cm above the bottom of the column. The strongly basic anion exchange resin layer is regenerated by discharging it from the intermediate collector (third step). Then, a total volume of 40 l of demineralized water was injected at a space velocity of 5 / hour, 20 l from the top and bottom of the column, respectively, and both resins were washed with water by discharging from the intermediate collector, and then pressurized from the bottom of the column. Introduce air to mix each resin layer and form a mixed bed
(4th step). After the regeneration operation was completed as described above, a sucrose solution (50 l for 1 batch) having the physical properties shown below was added at a solution temperature of 50.
The mixture was passed through a column mixed bed at a space velocity of 2 / hour at a temperature of ℃, and the electrical conductivity and the stamper color value (SCV) of the obtained treatment liquid were measured.

(Physical properties of sucrose solution) Electric conductivity 310 μS / cm Brix 50 pH 7.3 Stamper color value 0.3

When the sucrose solution has been decolorized and desalted, the mixed bed is regenerated by the above regeneration method.
The purification process of sucrose solution and the regeneration process of anion and cation exchange resin are repeated. The electrical conductivity [μS / cm · 25 ° C] measured for the treated solution discharged during the 30th purification of 50 l sucrose solution in this repetition is shown in Fig. 2 and the stamma color value is shown in Fig. 3. Show.

Comparative Example 1 A comparative test was conducted by using the same column as in Example 1 above and using a sucrose solution purifying apparatus in which a mixed bed was formed with an equal amount of resins of the same brand. Regeneration of the resin in this comparative example was performed as follows. First, flow demineralized water from the bottom of the column.
It was injected at an upward flow of 7.5 m / hour for 15 minutes, and stratified into a strongly basic anion exchange resin layer and a weakly acidic cation exchange resin layer. Next, pass an aqueous hydrochloric acid solution downward from the top of the column,
Drain the regeneration waste liquid from the bottom of the column. Following this, an aqueous solution of caustic soda was passed through from the upper end of the column, and the waste liquid for regeneration was discharged from an intermediate collector to regenerate both resin layers.

The concentrations of the respective regenerant liquids and the conditions for passing the chemicals were the same as in Example 1. Then, after regenerating both resin layers, washing with water is carried out by the same procedure as in Example 1, after which a mixed bed is formed, the next sucrose solution is purified, and the regeneration is further repeated. The purification treatment of the sucrose solution and the regeneration treatment of the ion exchange resin are repeated. Then, as in Example 1, the electrical conductivity and the stamper color value of the sucrose solution treated for the 30th time are measured. In order to compare the result with that of Example 1, the change in electrical conductivity is shown in FIG.
Fig. 3 shows the change in the color number of the stamper.

[0023]

EFFECTS OF THE INVENTION During regeneration of a mixed bed using a saline solution, the strong basic anion exchange resin layer and the weakly acidic cation exchange resin layer are separated very well, so that the regeneration is defective due to imperfect separation. Is eliminated, and at the same time, a regenerative operation is added to the strongly basic anion exchange resin, and the accumulation of dye components is prevented, so that a purified sucrose solution with stable purity can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic vertical cross-sectional view of a mixed bed type sucrose solution purifying apparatus used for carrying out the method of the present invention.

FIG. 2 is a comparative diagram showing changes in electric conductivity of treated sucrose solutions in Examples and Comparative Examples.

FIG. 3 is a comparative diagram of changes in the stamma-color value of treated sucrose solutions in Examples and Comparative Examples.

[Explanation of symbols]

 1 Resin Tower 2 Mixed Bed 3 Dispersion Tube 4 Lower Liquid Collection Tube 5 Intermediate Collector-

Claims (2)

[Claims] 1. A strong basic anion exchange resin and a weakly acidic cation exchange resin are used for regenerating a mixed bed type sucrose solution purifying apparatus filled with a strongly basic anion exchange resin and a weakly acidic cation exchange resin. First contacting hydrochloric acid solution to the mixed bed with resin
Step, a second step of injecting saline from the bottom of this mixed bed to stratify the strongly basic anion exchange resin layer and the weakly acidic cation exchange resin layer, and the strong basic anion exchange resin layer to the caustic soda layer. A mixed-bed sucrose solution, characterized in that a third step of contacting the Da solution and a fourth step of mixing the strongly basic anion exchange resin layer and the weakly acidic cation exchange resin layer are sequentially performed. Regeneration method of refining equipment. 2. The specific gravity of the saline solution used in the second step is the same as the specific gravity of the strongly basic anion exchange resin constituting the mixed bed in the loaded form, and the weak acidic cation which also constitutes the mixed bed. The method for regenerating a mixed-bed sucrose solution purifying apparatus according to claim 1, wherein the ion-exchange resin is adjusted to a specific gravity in a regenerated form.