JPS6314959B2 - - Google Patents

Description

[Detailed description of the invention]

This invention relates to a method for softening and decolorizing sugar solutions such as sucrose solution and sugar beet solution. Sugar solutions such as sucrose solution and beet sugar solution contain large amounts of impurities such as salts, organic substances, and pigments.
Efficient removal of these impurities is important from the viewpoint of increasing product yield and improving quality. In recent years, treatment methods using ion exchange resins have been used to remove these impurities, and various methods have been studied to date. The present invention particularly relates to a method of softening and decolorizing a sugar solution using an ion exchange resin after pretreatment such as a carbonation saturation method or an activated carbon treatment method. Conventionally, as a softening and decolorizing method for sugar solution, after subjecting the sugar solution to pretreatment such as carbonation filling method and activated carbon treatment method, Cl
The liquid is passed through a resin tower filled with a strongly basic anion exchange resin (hereinafter referred to as Cl type anion exchange resin), and subjected to a decoloring process that mainly removes the pigment components in the sugar solution. Next, this decolorized sugar solution was treated with Na type strongly acidic cation exchange resin (hereinafter referred to as Na
A method is known that consists of a step of passing the liquid through a resin tower filled with a type of cation exchange resin (abbreviated as cation exchange resin) and performing a softening treatment to mainly remove hard components from the sugar liquid. That is, the conventional method for softening and decolorizing sugar liquid is a two-column system, which has the drawbacks of a large number of resin columns, complicated piping, and complicated operation management. The present inventors have worked diligently to eliminate the above-mentioned difficulties, simplify the operational management of ion exchange equipment, and provide a method for simultaneously performing softening and decolorization in the same resin tower so that it can be operated with cheaper equipment. After repeated consideration,
As a result, at the moving speed of the adsorption zone that moves as a result of the adsorption of impurities by the positive and negative ion exchange resin,
The movement speed for softening by the Na-type cation exchange resin is made slower than the movement speed for decolorization by the Cl-type anion exchange resin. That is, it was discovered that the decoloring efficiency is better when decoloring is performed after softening, and the present invention has been achieved. That is, the gist of the present invention is that in a method for softening and decolorizing sugar solution using an ion exchange resin, the total ion exchange equivalent of the Na type strongly acidic cation exchange resin is equal to that of the Cl type strongly basic anion exchange resin. Soften and decolorize by passing the sugar solution through a mixed bed consisting of a Na-type strongly acidic cation exchange resin and a Cl-type strongly basic anion-exchange resin whose packed resin has been adjusted to be larger than the total ion exchange equivalent. The method is characterized in that when the ion exchange function of the ion exchange resin deteriorates, a salt-containing solution is passed through the mixed bed to simultaneously regenerate both resins. The present invention will be explained in detail below. As mentioned above, the method of decolorizing and softening a sugar solution has conventionally been carried out in two steps, a decolorization step and a softening step, in this order and divided into at least two steps.
When combining these two steps in one step, in order to simply perform them simultaneously in the same resin tower, the hardness component and pigment component in the liquid to be treated must be If an anionic and anionic ion exchange resin is used, the movement speed of the impurities adsorbed by each anionic and anionic ion exchange resin is about the same, so the Na type cation exchange resin and the Cl type anion exchange resin are each This means that treatment can be achieved by using a mixed bed packed in the same resin column in proportion to its capacity. However, it has been found that in order to increase the decolorizing effect, it is better to carry out the softening process and the decolorizing process in this order. This was clarified by the following experiment. 100% each of treated liquids A and B in Table 1 below
ml, into separate Erlenmeyer flasks, and add Cl type strong basic anion exchange resin Diaion SA11A to each flask.
(a product of Mitsubishi Chemical Industries, Ltd., Diaion is a registered trademark of the same company, the same applies to the following examples) was added thereto, and the mixture was allowed to react for 2 hours with occasional stirring, and the change in chromaticity after the reaction was measured. The results are shown in Table 1.

[Table] As shown in Table 1, the decolorization rate of treated liquid A is 23%, the decolorization rate of treated liquid B is 72%, and Ca
The coexistence of ions, that is, hardness components, significantly reduces the decolorization rate. Considering the above, in order to carry out the reaction in the above order in a mixed bed of anode and anode ion exchange resins,
The moving speed of the adsorption zone of Na-type cation exchange resin is Cl
It may be adjusted to follow the moving speed of the adsorption zone of the type ion exchange resin. To achieve this, the amount of packed resin should be such that the total ion exchange capacity of the Na type cation exchange resin is greater than the total ion exchange capacity of the Cl type anion exchange resin, so that the treatment is carried out in a mixed bed of both resins. By doing so, the decolorization step and the softening step can be performed in the same resin column without reducing the decolorization effect. In the method of the present invention, the mixing ratio of Na type cation exchange resin and Cl type anion exchange resin is 1.2:1 to 1.5:1 (total ion exchange It is preferable to set it within the range of (capacity ratio). As described above, the sugar solution is softened and decolorized, and when the processing capacity of the ion exchange resin decreases, it is regenerated. According to the method of the present invention, unlike other mixed bed type cases, there is no need to separate and regenerate both the positive and negative ion exchange resins, and the regenerating agent can simply be passed through the resin. As the regenerating agent, a solution containing salt may be used in an amount corresponding to the ion exchange capacity of the Na-type cation exchange resin. This salt-containing solution may be an aqueous solution containing only common salt, or an aqueous solution containing sodium chloride and caustic soda. A saline solution is usually used at a concentration of about 10%, and when adding caustic soda, the concentration is 10%.
It is preferable to use a saline solution containing 20 to 5% of the solid content of caustic soda based on the solid content of common salt.
The amount of the saline solution to be used is preferably in the range of 100 to 200 g in terms of solid salt content per resin. The temperature during the regeneration treatment may be room temperature, but the regeneration efficiency will be improved if the temperature is heated to 40 to 85°C. As described above, according to the method of the present invention, softening and decolorization can be simultaneously and effectively achieved in a single mixed-bed type column, and there is no need for regeneration and separation of anionic and anionic ion exchange resins. The process is simplified and operation management is also simplified, which is extremely advantageous in terms of industrial implementation. Next, embodiments of the present invention will be described. Example 1 Na-type strong acid cation exchange resin Diamond
SK1B [manufactured by Mitsubishi Chemical Industries, Ltd.] 100ml (total ion exchange capacity 0.19 equivalent) and Cl type strong basic anion exchange resin Diaion PA312 [manufactured by Mitsubishi Chemical Industries, Ltd.] 100ml
(total ion exchange capacity: 0.12 equivalents) was packed into a jacketed glass column with an inner diameter of 20 mm, mixed, and then added to the beet sugar solution 4 shown in Table 2 below.
SV3hr ^-1 and the liquid was passed at a temperature of about 60°C.

[Table] Next, add 200ml of a 10% by weight saline solution to the mixed resins in the column as a regenerant.
After passing at SV2hr ^-1 , 1000 ml of demineralized water was passed at SV10hr ^-1 for regeneration. When the beet sugar solution 4 shown in Table 2 above was passed through this regenerated mixed layer at an SV of 3 hr ^-1 , the decolorization rate of the treated sugar solution gradually decreased from the initial 85%, and the decolorization rate at the time of 4 liquid passes. was 60%, and the leakage of calcium ions at this time was 2 ppm or less. Comparative Example A comparative experiment was conducted for the case in which the amount of Na type cation exchange resin in Example 1 was reduced. Na-type strong acid cation exchange resin Diamond ion
20 ml of SK1B (total ion exchange capacity 0.038 equivalent) and
Cl type strong basic anion exchange resin Diamond ion
Pack 100 ml of PA312 (total ion exchange capacity 0.12 equivalents) into a jacketed glass column with an inner diameter of 20 mm.
Both resins were mixed. The subsequent conditions for passing the sugar solution to be treated, the conditions for regenerating the mixed layer, and the conditions for passing the sugar solution to be treated after regeneration were the same as in Example 1. As a result, in the sugar solution treatment after regeneration treatment, the leakage of calcium ions from the treatment solution was less than 2 ppm up to a flow rate of 1.5, but rapidly increased to 63 ppm after a flow of 1.6. In addition, the decolorization rate of the treatment solution gradually decreased from 78% at the initial stage of liquid passage, and color leakage suddenly increased after 1.5 liquid passages, and the decolorization rate decreased to 50% or less. What has been explained above and shown in the examples is related to typical examples to help the understanding of the present invention, and the present invention is not limited to these examples, and other changes may be made within the gist of the invention. , variations can be taken.

Claims (1)

[Claims] 1 In the method of softening and decolorizing sugar solution using an ion exchange resin, the total ion exchange equivalent of the Na type strongly acidic cation exchange resin is made larger than the total ion exchange equivalent of the Cl type strongly basic anion exchange resin. A sugar solution is passed through a mixed bed consisting of a Na-type strongly acidic cation exchange resin and a Cl-type strongly basic anion exchange resin, in which the filled resin is adjusted to soften and decolorize the ion exchange function of the ion exchange resin. When the resin decreases, a solution containing salt is passed through the mixed bed to simultaneously regenerate both resins.