JP2000184900A - Method and device for purifying starch sugar solution - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for purifying a starch sugar solution, capable of stably giving the pure sugar solution having a high purity and a good quality and scarcely containing resins. SOLUTION: This device for purifying a starch sugar solution comprises a cation tower 1 in which a strongly acidic cation exchange resin layer 101 is charged in a packed bed type and an anion tower 4 wherein a weakly basic anion exchange resin 402 is charged in a packed bed type in the lower chamber among the upper and lower chambers formed by dividing the anion tower 4 with a dividing plate 401 inhibiting the passage of resin granules and a strongly acidic anion exchange resin 403 is charged in the upper chamber in a packed bed type. Therein, the sugar solution to be purified is passed through the cation tower 1 as an downward flow in the cation tower 1, and the sugar solution is passed through the anion tower 4 as an upward flow to purify the sugar solution. The regeneration of the ion exchange resins is carried out by countercurrently flowing each regenerating agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method and an apparatus for purifying a starch sugar solution using an ion exchange resin.

[0002]

2. Description of the Related Art Starch sugar includes glucose, isomerized sugar, starch syrup, maltose, and the like. Also, sorbitol produced by reducing these is considered to be included in the concept of starch sugar because the raw material is starch. Generally, ion exchange resins have been used for a long time to purify these sugar solutions.

The UD type starch sugar refining apparatus shown in FIG. 2 is a typical example of such an apparatus, which is a K column (cation column) -A column (anion column) -MB column (mixed bed column). ) Has a three-column shape in which the sugar solution is passed through each column in a downward flow.
The column is filled with a standard gel-type strongly acidic cation exchange resin 6 of about 8% DVB (divinylbenzene) to perform a descending flow liquid, and an upflow regeneration method is employed. Note that the MB column in FIG. 2 shows a state in which a strongly acidic cation exchange resin and a strongly basic anion exchange resin are backwashed and allowed to stand for specific gravity separation for regeneration treatment. Being mixed floor.

[0004] The reason for adopting the upflow regeneration method in the K tower, which is a feature of the UD system, is as follows. That is, since the sugar molecule has a property of easily decomposing in the alkaline region, the tower A is used after being filled with the weakly basic anion exchange resin 7, but the ion exchange reaction by the weakly basic anion exchange resin 7 is medium. Since it is a sum reaction, the efficiency of deanion depends on the ion exchange efficiency in the preceding K tower. Therefore, the countercurrent contact system in which the regeneration of the K tower is performed by an upward flow improves the ion exchange efficiency, minimizes the leakage of cationic impurities from the K tower, and improves the purity of the treatment liquid in the A tower. I did it.

According to the UD method, the purity of the treatment liquid in the tower A is improved by about 10 times in average resistivity as compared with the starch purification apparatus in which the tower K is used in a downflow regeneration method. This has the advantage that the load on the subsequent MB column is significantly reduced, and the amount of ion exchange resin in the MB column can be reduced. The MB column is installed because, in the weakly basic anion exchange resin used in the anion column, a slight amount of weak acid or color leaks due to its inherent properties, and with this leak, the pH of the processing solution gradually increases.
Is inevitable to change. That is, the pressure is high at the start of the liquid passage and decreases with an increase in the liquid passage amount. Therefore, as a final finishing step, a mixed bed tower (MB tower) using a strongly basic anion exchange resin 8 and a strongly acidic cation exchange resin 9 is installed as a polisher to remove the weak acid and color and to send the sugar liquid to the concentration step. Is adjusted to a constant pH.
The sugar liquid purified by the ion exchange resin is concentrated to produce a product, but is heated in the concentration step,
The pH of the processing solution from the final MB tower is generally made slightly more acidic than neutral so as to prevent heat coloring.

[0006]

The present inventors have found that the above-mentioned starch sugar refining apparatus of the UD system which has the above-mentioned advantages still has a problem to be further improved. .

That is, in the above-described apparatus, since the K column is an upflow regeneration, it is necessary to pass the medicine at a low flow rate so that the packed bed does not flow during the passage of the regeneration medicine in order to perform good regeneration. There is a problem that it takes a long time to regenerate, and if the collector that collects the reclaimed effluent is exposed from the filled resin layer, the ion-exchange resin flows and the regeneration becomes insufficient. However, there is a problem that management becomes important in operation management. Monitoring and management of the position of the resin layer surface is necessary in the above-mentioned equipment.
This is because a part of the ion exchange resin flows out of the column at the time of back washing by repeating refining and regeneration, and the amount of the resin usually decreases. Therefore, when the amount of resin decreases, it is necessary to replenish the ion-exchange resin and adjust the resin layer surface. Generally, an operation of replenishing the resin at regular intervals is performed. It can be said that it is desired to eliminate the problem of complicated management and time-consuming reproduction.

[0008] As another problem, the K tower and the A tower are usually provided so that an upper space called a free board exists in the resin tower in order to create a space for backwashing. However, if a low pH sugar solution is retained on the free board of the tower A for a long time, sugar molecules are decomposed. Therefore, it is desired that the liquid level in the free board be operated as low as possible. According to the method, the droplets generated when the sugar liquid supplied from the upper part of the resin tower falls to the liquid surface adhere to and decay on the inner wall of the tower, and as a result, the quality of the sugar liquid deteriorates due to the microorganism-derived slime generated as a result. This leads to another problem. Therefore, it is important to solve this problem in order to improve product quality.

Further, as described above, the MB tower (mixed bed tower)
The purpose is to stabilize the pH of the processing solution by adsorbing and removing weak acid components that could not be completely removed in the tower A, so that the ion exchange in the first tower K and the tower A is sufficiently complete. This is an element that is originally unnecessary if it is performed. However, such a complete treatment is difficult in an actual apparatus, so that a sugar solution is brought into contact with a strongly basic anion exchange resin for finishing treatment, but alkali decomposition of sugar molecules is minimized. In order to reduce the apparent alkalinity, a mixed-bed column containing a strongly acidic cation exchange resin was used to select the appropriate type of ion exchange resin suitable for suppressing the decomposition of sugar molecules. Some ideas such as setting (low temperature) are also made. By adopting the UD method as described above, the amount of resin in the MB tower can be reduced as compared with the conventional apparatus in which the K tower is regenerated by a downward flow, and the flow rate can be increased. Was. However, it goes without saying that a further reduction in the amount of resin is desired.

[0010] Further, as one of the more important problems, there is a problem that it is desired to suppress as much as possible the sugar loss generated in proportion to the amount of the filled resin. That is, since a large amount of the sugar component permeates into the resin particles of the ion exchange resin that comes into contact with the sugar solution during the passage, generally before a certain purification treatment operation is completed and regeneration is performed, Then, an operation (sweetening off) of extruding and collecting the sugar component permeated into the resin particles is performed. However, a large amount of hot water (or water) is required to completely extrude and recover the sugar components,
Since the concentration of the recovered sugar solution is reduced and the cost of the subsequent concentration step is increased, the extrusion and recovery of the sugar component in the resin particles by warm water is usually terminated at an appropriate concentration. For this reason, the unrecovered sugar components remaining in the resin particles gradually exude during the regeneration treatment, and this becomes a loss of the sugar components, and the amount thereof is approximately proportional to the amount of the charged resin in the entire apparatus. In addition, the exuded sugar component not only causes a loss of the sugar component but also increases the BOD of the reclaimed wastewater, thereby increasing the burden of wastewater treatment.

As described above, the starch-sugar-purifying apparatus of the UD system is currently widely used due to its excellent advantages.
The above-mentioned problems to be further solved were also found, and the present inventor has made research based on such findings and completed the present invention.

[0012]

Means for Solving the Problems In order to solve the above problems, the present inventor has made the inventions described in the respective claims.

[0013] The invention of the method for purifying a starch sugar solution according to claim 1 of the present invention comprises a cation column packed with a strongly acidic cation exchange resin, a lower chamber packed with a weakly basic anion exchange resin in a packed bed type, In addition, the sugar solution purification is performed by passing the anion column partitioned into an upper chamber packed with a strongly basic anion exchange resin in a packed bed type in a downward flow and flowing the anion column in an upward flow. The regeneration operation is performed in this order, and the regeneration operation is performed by passing the regenerant through the cation tower in an ascending flow and passing the regenerant through the anion tower in a descending flow.

In the above configuration, the packed bed type means, in principle, that the ion exchange resin is “full in the most swollen state” in the entire space filled with the ion exchange resin.
It means that it is in a state of being filled. That is, as is well known, the ion exchange resin contracts in the state of an exchange group (Na type and H type for a strongly acidic cation exchange resin, and OH type and Cl type which are free base forms for a weakly basic anion exchange resin).・ Because it expands and contracts and expands in water, under acid or alkali solution, or under sugar solution due to the osmotic pressure of the solution, a space less than resin may be generated in the filling space depending on the conditions. However, the term "packed bed-type filling" as used in the present invention means that the ion exchange resin is fully swollen and full under the use environment of the present invention. Generally, the degree of shrinkage / expansion of a strongly acidic cation exchange resin is 3 to 6
%, And a weakly basic anion exchange resin that shrinks / expands at most about 30% is known. And according to the configuration of the present invention in which the direction of each ion exchange resin and the passage of the sugar liquid to the resin and the direction of the passage of the regenerating agent are specified, as described later, there is no "packed bed type filling" in the prior art. Excellent effects are achieved.

In this "packed bed type filling" mode, the backwashing operation to be performed when the suspended matter accompanying the stock solution flows into the resin tower and the pressure loss in the flowing state increases. Since it is not possible, in the case of an apparatus that requires backwashing, it is possible to adopt a method of installing a separate backwashing tower and, if necessary, transferring a part of the ion exchange resin to the backwashing tower for backwashing. .

In the cation tower filled with the cation exchange resin used in the present invention, it is desirable to use a packed bed type packed with the above resin to fill the regenerant at a high flow rate. In view of the properties of the exchange resin and the direction of liquid passage and chemical transfer, an appropriate space (a space remaining even when the resin swells maximum) is provided above the cation tower without being limited to such packed bed type filling mode. It may be in a state filled so as to have. That is, the strongly acidic cation exchange resin (for example, Amberlite (registered trademark) IR124) generally used in the present invention is an ion exchange resin having a high degree of cross-linking, and therefore has a high true density and a small shrinkage rate when a regenerant is passed. This is because the flow during the upflow regeneration is unlikely to occur, so that stable regeneration can be performed even if a space of an appropriate size is left as described above. Further, since the sugar solution flow is a downward flow, the upper space does not cause any trouble. The size of the space that can be set to remain even during such maximum swelling is not determined in principle,
It can be appropriately determined in consideration of the tower height of the implementation facility, the handleability of the filled resin, and the like.

The anion tower filled with an anion exchange resin is used in the above-mentioned "packed bed type packing" mode in which the resin is filled in a space. This filling mode employed in the present invention has an extremely excellent effect in combination with the properties of the anion exchange resin and the directions of liquid passage and drug passage. That is, since the flow of the regenerating agent is a downward flow, the regenerating operation can be performed without any problem even if there is a space above. On the other hand, in the operation of flowing a sugar solution in an ascending flow, the anion exchange resin is generally porous and thus has a low true density and floats in a starch sugar solution having a sugar concentration of 30 to 40% to start flowing. At the same time, since a substantially packed bed state is exhibited on the upper side of the filling space, even if there is a space associated with resin shrinkage in the lower part of the filling space, there is no hindrance to the passage of the sugar solution. As described above, the “packed bed-type filling” of the resin in the anion tower provides a good effect in any case even if the resin contracts and expands due to the passage of the sugar solution and the passage of the regenerant. be able to.

According to the present invention, the anion tower is divided into the upper and lower chambers as described above, and the weakly basic anion exchange resin and the strongly basic anion exchange resin are filled in packed beds, respectively, and By passing the liquid in ascending flow, the three-tower type device in the conventional UD type device can be used.
There is an advantage that the apparatus can be a two-tower type apparatus that does not require an MB tower.

The present invention also requires that the operation of passing the sugar liquid through the cation tower in a descending flow and passing the sugar liquid through the anion tower in an ascending flow be performed in this order. -Weakly basic anion exchange resin-Strongly basic anion exchange resin is passed in this order for efficient purification of the sugar solution, and the direction of sugar solution flow in the anion tower is an ascending flow. The problem of the generation of slime due to the sticking of the sugar solution, which has been a problem in the anion tower of the UD system, is solved.

Further, since it is essential to carry out the regeneration operation for the cation column by passing the regenerant through an upward flow, and for the anion column to pass the regenerant through a downward flow, it is essential to carry out the cation exchange resin. In addition, both the anion exchange resin and the anion exchange resin are countercurrently regenerated, improving the degree of purification and improving the quality stability of the obtained sugar solution.

Furthermore, according to the present invention, a weakly basic anion exchange resin and a strongly basic anion exchange resin are packed in two layers in one column to form a strongly basic anion exchange resin which constitutes a conventional polisher. MB column consisting of a mixed bed of a strong acid and a cation exchange resin can be omitted, reducing the construction cost of the equipment, reducing the installation area, reducing the amount of resin, and reducing the purification and regeneration costs through these.
Three types of ion exchange resins are used.
The strongly acidic cation exchange resin (usually different from the same cation exchange resin in the cation tower) packed in the column can be unnecessary.

Furthermore, when each of the cation column and the anion column is used in the packed state of the packed bed described above, both columns can be made smaller than the conventional UD type apparatus. Further, by using a packed bed type cation tower, there is also obtained an advantage that a drug can be passed at a high flow rate during regeneration.

In the sweetening-off operation in which the sugar remaining in the resin tower is extruded with hot water after the completion of the flow of the purification treatment, the hot water and the sugar solution may be extruded and replaced as little as possible. It is important to consider the density difference (specific gravity difference) between the sugar solution and the hot water. In the cation tower, the ideal sweetening off is performed because the hot water descends and the hot sugar solution is extruded with the high density sugar solution downward. Is achieved. On the other hand, in the anion tower, the pushing operation by the rising flow of warm water is performed, but in the warm water pushed out from the cation tower and transferred to the anion tower, a certain dilution of the sugar solution occurs, so that the There is no problem because mixing due to the density difference does not substantially occur. Therefore, it is advantageous in reducing the loss due to good extrusion of the sugar content at the time of sweetening off, and in reducing the wastewater treatment load due to the increase in BOD due to the leakage of the sugar content into the regeneration wastewater.

According to a third aspect of the present invention, there is provided a starch sugar sugar liquid refining apparatus comprising a cation column filled with a strongly acidic cation exchange resin, and a partition for allowing the liquid to flow in the column but preventing the resin particles from flowing. An anion column in which the lower chamber is packed with a weakly basic anion exchange resin in a packed bed and the upper chamber is packed with a strongly basic anion exchange resin in a packed bed, and a sugar to be purified. After passing the liquid from the upper part to the lower part of the cation tower, a sugar liquid distribution pipe connected so as to flow from the lower part to the upper part of the anion tower, and a regenerant from the lower part to the upper part with respect to the cation tower. A cation exchange resin regenerant flow pipe connected to pass the medicine, and an anion exchange resin regenerant flow pipe connected to pass the regenerant from the upper part to the lower part with respect to the anion tower. It is characterized in.

In the above configuration, a general partition such as a slit screen or a strainer can be used as a partition for dividing the upper and lower chambers of the anion tower. The partition position is determined by the volume ratio of the weakly basic anion exchange resin (for example, Amberlite XE583) to be filled in the lower chamber and the strong anion exchange resin (for example, Amberlite IRA411S) to be filled in the upper chamber. The appropriate volume ratio is not always the same depending on the type of sugar solution to be determined and treated, but generally, the position is 10 to 30% from the upper part of the packed space in the tower that stands upright with the same horizontal section, preferably 15%. It is preferable that the ratio is given by partitioning vertically at the position.

The supply of the regenerant and the discharge of the drainage are appropriately performed according to the filling state of the ion-exchange resin into the resin filling space (a state in which a space is taken into account in consideration of shrinkage and swelling of the resin). A distributor, a collector, and the like can be used as needed.

According to the present invention, the above-described method of claim 1 can be carried out. Therefore, the anion tower is packed in a packed bed, and the cation tower is preferably packed in a packed bed. , Conventional UD
It can be a small tower compared to the system of the system. In addition, since the sugar liquid is passed through the cation tower in a descending flow, and then passed through the anion tower in an ascending flow, the sugar adhering, which has been a problem in the anion tower of the conventional UD system, is performed. This eliminates the problem of slime generation. Furthermore, since the regeneration operation is carried out by passing the regenerant through the ascending flow for the cation column and passing the regenerant through the downward flow for the anion column, the countercurrent regeneration system is used, so that the purification degree can be improved and obtained. The quality stability of the sugar solution is improved.

Further, the anion tower has a weakly basic anion exchange resin and a strongly basic anion exchange resin in two layers, and the conventional polisher (MB tower) can be omitted.
It is possible to reduce the construction cost of the apparatus, reduce the installation area, reduce the amount of resin, and reduce the purification and regeneration costs through these.

[0029]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an outline of a starch sugar liquid refining apparatus according to a first embodiment of the present invention, in which a packed bed 1 is filled with a strongly acidic cation exchange resin so as to fill a filling space. A cation tower packed in a mold, and a stock solution, which is a sugar solution before purification, is supplied from the top of the tower, flows through the strongly acidic cation exchange resin layer 101 in a downward flow, and is discharged from the bottom of the sugar solution. Distribution pipes 201 and 202 are connected. Reference numeral 102 denotes a strainer provided on the upper portion of the cation exchange resin packed bed, which is adopted for packed bed type packing and realizes high flow rate of the regenerating agent which suppresses the flow of the resin during the regeneration process. . 103 is a water collecting mechanism provided below the cation exchange resin packed layer.

For the regeneration treatment, hydrochloric acid (HCl), which is a regenerant for the cation exchange resin, is supplied from the bottom of the column, flows through the strongly acidic cation exchange resin layer 101 in ascending flow, and regenerates wastewater from the top of the column. Is connected to the regenerant distribution pipe 3 so as to be discharged.

Reference numeral 4 denotes an anion column in which a weakly basic anion exchange resin and a strongly basic anion exchange resin are packed in two layers, and a partition plate provided in the column 3 at a position of about 20 to 30% from the top. The lower chamber is filled with a weakly basic anion exchange resin in a packed bed so as to fill the lower chamber with a weakly basic anion exchange resin layer 402 to form a weakly basic anion exchange resin layer 402. The chamber is filled with a strongly basic anion exchange resin in a packed bed so as to be filled with the strongly basic anion exchange resin layer 40.
3 are provided. The sugar liquid passed through the cation tower 1 is supplied to the anion tower 4 via a pipe 2.
02 from the bottom of the column, the weakly basic anion exchange resin layer 402 and then the strongly basic anion exchange resin layer 40
3 through the ascending flow, and the purified liquid is discharged from the top of the column through the sugar liquid distribution pipe 203. 404
405 is a strainer provided above the strongly basic anion exchange resin packed layer 403, and 405 is a water collecting mechanism provided below the weakly basic anion exchange resin packed layer 402.

For the regeneration treatment, sodium hydroxide (NaOH), which is a regenerating agent for the anion exchange resin, is supplied from the top of the tower to form a strongly basic anion exchange resin layer 403 and then a weakly basic anion exchange resin layer 402. The regenerating agent flow pipe 5 is connected so that the regenerated effluent is discharged from the bottom of the tower through the chemical flow in the downward flow.

In order to regenerate each ion exchange resin in the cation tower 1 and the anion tower 4, or to carry out backwashing treatment when the pressure loss increases due to the inflow of suspended substances, some or all of these resins are removed. A backwash tower (not shown) for transfer may be provided for each resin.

In the starch sugar liquid refining apparatus constructed as described above, at the time of purification, the undiluted liquid (sugar liquid) is passed through to convert the sugar liquid into the strongly acidic cation exchange resin layer 101-weakly basic anion exchange liquid. The resin solution is efficiently purified while being passed through the resin layer 402 and the strongly basic anion exchange resin layer 403 in this order. In the anion tower 4, the sugar solution is passed through the anion tower 4 in ascending flow. There is no problem of slime generated due to the adhesion and decay of the droplets on the inner wall of the tower.

In addition, by passing the regenerating agent in the cation tower 1 in ascending flow and in the anion tower 4 in descending flow, all can be countercurrently regenerated, and as a result, good regeneration can be obtained. It is possible to regenerate the ion exchange efficiency. Therefore, the purification degree is improved, and the quality stability of the obtained sugar solution is improved.

The apparatus of the present embodiment for performing the above-mentioned sugar solution refining treatment and countercurrent regeneration has a smaller amount of resin than a conventional UD type apparatus and does not have a mixed bed of an MB column. The number of types of exchange resin may be less than one. From these facts, it is possible to reduce the size of the apparatus and reduce the amount of sugar components that penetrate into the resin particles and result in loss.

[0037]

EXAMPLES Example 1 The apparatus shown in FIG. 1 was constructed as follows to purify a sugar solution.

Cation tower 1 Strongly acidic cation exchange resin: Amberlite IR124 Amount of resin completely filled in filling space: 500 ml Anion tower 4 Weakly basic anion exchange resin: Amberlite XE583 Amount of resin fully filled in lower chamber 402: 500 ml strong Basic anion exchange resin: Amberlite IRA41
1S Amount of resin fully filled in the upper chamber 403: 100 ml Regeneration treatment Cation column regenerant: 35% HCl 250 g / l-R
Use 5% solution Anion tower regenerant: 100% NaOH 60 g / l-R
A 4% solution is used, however, the amount of the anion tower regenerant is based on the amount of resin completely filled in the lower chamber 402.

Comparative Example 1 Cation tower 1 Strongly acidic cation exchange resin: Amberlite IR120B Filled resin amount: 500 ml Anion tower 4 Weakly basic anion exchange resin: Amberlite XE583 Filled resin amount: 500 ml MB (mixed bed) tower Strong basicity Anion exchange resin: Amberlite IRA41
1S Filled resin amount: 300 ml Strongly acidic cation exchange resin: Amberlite 200C Filled resin amount: 150 ml Regeneration treatment Cation tower regenerant: 35% HCl 250 g / l-R
Use 5% solution Anion tower regenerant: 100% NaOH 60 g / l-R
Using 4% solution MB (mixed bed) tower: 35% HCl 150 g / l-R
Using 3.5% Solution Using 100% NaOH 80 g / l-R 4% Solution Under the above conditions, the regeneration treatment and the sugar solution purification treatment were repeated three times for each of Example 1 and Comparative Example 1. The results of the third test, which is considered to be in a stable state, will be illustrated and described.

The stock solution (sugar solution) used in the test had the following properties.

Isomerized sugar solution Brix 31 F% (fructose content) 48% pH 4.1 Color (-logT 420 nm, 50 mm) 0.073 Resistivity (25 ° C.) 4.400 Ω · cm All cationic impurities 330 mg CaCO ₃ / L Total anionic impurities 540 mg CaCO ₃ / l The flow conditions were as follows: the flow rate was 4 liters / h, and the processing liquid was 40 ° C.
The temperature was adjusted so that

FIG. 3 shows the test results. In Example 1, the outlet liquid of the anion tower 4 was measured, and in Comparative Example 1, the outlet liquid of the MB (mixed bed) tower was measured for resistivity and pH at 25 ° C.

After the passage of 40 liters, the inlet was switched to warm water at 40 ° C., and the state in which the sugar solution was pushed out of the resin tower (sweetening off) was measured by the change in sugar concentration. The result is shown in FIG.

In Comparative Example 1, in order to minimize the influence of the durable space in the resin tower, the liquid level remaining at the top of each resin tower was lowered to a position of 130 with respect to the packed bed height of 100, and then the hot water was removed. Switched to extrusion by
As shown in FIG. 4, complete extrusion was not possible even after 3 liters. On the other hand, in Example 1, the extrusion was completed at 2.3 liters.

Further, the amount of the regenerant required to treat 40 liters is as shown in Table 1 below, and it has been confirmed that the present invention achieves 15% reduction in hydrochloric acid and 45% reduction in sodium hydroxide. Was.

[0046]

[Table 1]

As can be seen from the comparison between Example 1 and Comparative Example 1, the total amount of resin used when performing the same amount of sugar solution treatment is smaller than that of the UD type apparatus of Comparative Example 1 in Example 1. It is clearly less used in equipment (about 20% in the above example)
From the results of FIG. 3, it can be seen that the purity of the sugar solution obtained by the purification is good.

[0048]

As described above, according to the first aspect of the present invention, since the anion column is used in the packed-bed-type packed state described above, each column is compared with the conventional UD type apparatus. In addition to being able to be a small column, it is necessary to perform the operation of passing the sugar solution through the cation column in a downward flow and passing the sugar solution through the anion column in an upward flow in this order.
The problem of the generation of slime due to the adhesion of the sugar solution, which has been a problem in the anion tower of the D-type apparatus, is solved.

Furthermore, in the regeneration operation, the regenerant is passed through the ascending flow in the cation tower and the regenerant is passed through the downflow in the anion tower, so that both the cation exchange resin and the anion exchange resin are countercurrently regenerated. As a result, the purification degree is improved and the quality stability of the obtained sugar solution is improved.

Further, by packing the weakly basic anion exchange resin and the strongly basic anion exchange resin in two layers in one column, the conventional polisher (MB column) can be omitted, and the construction cost of the apparatus can be reduced. Thus, it is possible to reduce the installation area, the amount of resin, and the cost of purification and regeneration through these. In addition, three types of ion exchange resins are used,
The need for the strongly acidic cation exchange resin packed in the conventional mixed-bed MB tower can be eliminated.

Furthermore, by packing the cation tower in a packed bed type, it is possible to carry out the ascending circulation of the regenerant at a high flow rate.

In addition, in the operation at the time of sweetening off after the completion of the purification flow, ideal extrusion of sugar by the descending flowing liquid of the hot water in the cation column is realized, and the rising flow of the warm water in the anion column is realized. Extrusion does not substantially cause mixing problems due to density differences as described above,
The effects of reducing the loss due to good extrusion of the sugar content at the time of sweetening off and reducing the burden of wastewater treatment due to an increase in BOD leaking during the regeneration wastewater are exhibited.

According to the third aspect of the present invention, the above-described methods of the first and second aspects can be carried out. Therefore, the packed bed type anion column is smaller in size than the conventional UD type apparatus. Tower. In addition, since the sugar liquid is passed through the anion tower in ascending flow, the problem of slime generation due to the adhesion of the sugar liquid, which has been a problem in the anion tower of the conventional UD system, is eliminated. For the cation tower, the regenerant is passed through the ascending flow, and for the anion tower, the regenerant is passed through the downflow. Quality stability is improved. When the cation tower is packed as a packed bed, the effect of increasing the flow rate of the regenerating agent at a high flow rate can be obtained.

Further, since the anion tower has a weakly basic anion exchange resin and a strongly basic anion exchange resin in two layers, the conventional polisher (MB tower) can be omitted, and the construction cost of the apparatus can be reduced and installation is possible. It is possible to reduce the area, reduce the amount of resin, and reduce the cost of refining and regeneration through these.

[0055]

[Brief description of the drawings]

FIG. 1 is a diagram showing an outline of the configuration of an apparatus used for refining a starch sugar solution according to a first embodiment of the present invention.

FIG. 2 is a diagram showing an outline of the configuration of an apparatus used for purification of a conventional UD starch sugar solution.

FIG. 3 is a view showing a test result obtained by performing a sugar solution passing process using the apparatus shown in FIGS. 1 and 2;

FIG. 4 is a view showing a result of measuring a state (sweetening off) in which a sugar solution is extruded by warm water after a liquid passing process by a change in sugar solution concentration.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Cation tower 101 ... Strongly acidic cation exchange resin layer 102 ... Strainer 103 ... Water collecting mechanism 201, 202, 203 ... Sugar liquid distribution piping 3, 5 ... Regenerant distribution piping 4 ... anion tower 401 ... strainer (partition plate) 402 ... weakly basic anion exchange resin layer 403 ... strongly basic anion exchange resin layer. 404: strainer 405: water collecting mechanism

Claims (4)

[Claims] 1. A cation tower filled with a strongly acidic cation exchange resin, a lower chamber packed with a weakly basic anion exchange resin in a packed bed, and a packed bed with a strongly basic anion exchange resin. With respect to the anion tower partitioned into the upper chamber, in the sugar solution purification, the operation of passing the liquid through the cation tower in a downward flow and the flow through the anion tower in the upward flow are performed in this order, and the regeneration operation is performed in the cation tower. A method for purifying a starch sugar solution, comprising passing a regenerating agent in an ascending flow and passing a regenerating agent in a descending flow through an anion tower. 2. The method for purifying a starch sugar solution according to claim 1, wherein the cation tower is packed with a strongly acidic cation exchange resin in a packed bed. 3. A cation column filled with a strongly acidic cation exchange resin, and a partition which allows the flow of liquid in the column but blocks the flow of resin particles, and is partitioned into upper and lower sections. An anion exchange resin was packed in a packed bed type, and an anion column filled with a strongly basic anion exchange resin in a packed bed type in the upper chamber, and a sugar solution to be purified was passed from the upper part to the lower part of the cation tower. And a saccharide exchange pipe connected so that the liquid flows from the lower part to the upper part of the anion tower, and a cation exchange resin regenerant connected so that the regenerant flows from the lower part to the upper part with respect to the cation tower. And a flow pipe for an anion exchange resin regenerant connected from the upper part to the lower part of the anion tower so that the regenerant passes therethrough. . 4. The apparatus for purifying a starch sugar solution according to claim 3, wherein the cation column is packed with a strongly acidic cation exchange resin in a packed bed type.