JPH059077B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for purifying sucrose solutions such as cane sugar and beet sugar. Conventionally, in order to purify a sucrose solution such as cane sugar, it is common to go through the steps shown below. That is, the raw sugar is first washed to remove impurities attached to the surface, then the washed sugar is dissolved in water and/or sweet water to make a raw sugar solution, and lime and carbon dioxide are added to the raw sugar solution. In addition, the resulting calcium carbonate is subjected to a chemical treatment such as so-called carbonation, in which impurities such as suspended solids and pigment components are adsorbed and removed, and then treated with activated carbon or bone char to remove remaining impurities, especially pigment components. The purified sucrose solution is then removed and further passed through a granular ion exchange resin layer for decolorization or decolorization and desalting. In this way, in conventional purification processes, adsorption treatment using activated carbon or bone char and adsorption treatment using a granular ion exchange resin layer are performed to remove pigment components contained in sucrose solutions having high color values. It is being done. By the way, when performing adsorption treatment using activated carbon or bone char as described above, running costs are enormous because the adsorption capacity of these activated carbon and bone char is low and it is necessary to replenish a considerable amount. At the same time, extra steps such as a deashing step and a filtration step are required, which makes the process complicated and reduces productivity. On the other hand, in the refining process using the above-mentioned granular ion exchange resin, the through-flow capacity decreases due to factors such as a decrease in exchange capacity and a decrease in intra-particle diffusion rate due to organic contamination where organic substances are irreversibly adsorbed on the particle surface. Due to a decrease in the purity of the liquid, the granular ion exchange resin is replaced with a new one at some point, and the used resin is discarded as industrial waste. Therefore, since the granular ion exchange resin is expensive, not only does the running cost increase, but the disposal of the used resin, which is industrial waste, has become a problem from the standpoint of pollution. As described above, in the conventional method for purifying a sucrose solution, there is a lot of waste when viewed as an industrial scale system, and as a result, this is reflected in the cost of the product. Therefore, the inventors of the present invention have conducted various studies to simplify the sucrose solution purification system and effectively utilize industrial waste, and have found that the dye adsorption ability of powdered anion exchange resin is the same as that of powdered activated carbon. and is recyclable; therefore, a sucrose solution after carbonation can be effectively purified by carrying out two-stage adsorption of a powdered anion exchange resin and a granular ion exchange resin; It is possible to crush the granular anion exchange resin whose capacity has decreased and reuse it as a powdered anion exchange resin, and the recycled waste liquid of the granular ion exchange resin can be used as a regenerating agent for the powdered anion exchange resin. I came to know that. The present invention has been made based on the above-mentioned findings, and the first invention includes a decoloring step in which adsorbed substances, mainly dyes, are removed by contacting a sucrose solution with a powdered anion exchange resin, and a strong base The powdered anion exchange resin used in the decolorization step is brought into contact with a solution containing acid and/or metal ions to remove the adsorbed substance. The invention is characterized in that it can be regenerated and used repeatedly by desorbing it, and the second invention involves contacting a sucrose solution with a powdered anion exchange resin to remove adsorbed substances, mainly pigments. A bleaching process,
It consists of a purification process in which the powdered anion exchange resin used in the decolorization process is brought into contact with a granular ion exchange resin mainly composed of a strongly basic anion exchange resin, and the granular ion exchange resin used in the refining process is crushed. It is a powdered anion exchange resin produced by the method, and is characterized in that it can be regenerated and used repeatedly by contacting the powdered anion exchange resin with an acid and/or metal ion-containing solution to desorb the adsorbed substance. Furthermore, the third invention includes a decoloring step in which a sucrose solution is brought into contact with a powdered anion exchange resin to remove adsorbed substances, mainly dyes, and a strongly basic anion exchange resin. The powdered anion exchange resin used in the decolorization step is a powdered anion exchange resin produced by pulverizing the particulate ion exchange resin used in the purification step, and Moreover, this powdered anion exchange resin is brought into contact with the regenerated waste liquid of the granular ion exchange resin used in the above purification step to desorb the adsorbed substance, thereby being regenerated and used repeatedly. An example of an embodiment of the present invention will be described below with reference to the flowchart shown in FIG. In this example, first, raw sugar is washed in a conventional manner in a sugar washing step 1 to wash off impurities attached to the surface of the raw sugar, and then in a dissolution step 2, the sugar is dissolved in a conventional manner. Generate a solution. As described below, the present invention includes a decoloring step that strongly adsorbs pigment components using a powdered anion exchange resin, so in some cases, the sugar washing step 1 may be omitted entirely or the washing water may be used. The amount can be significantly reduced. Next, a chemical treatment step 3 is performed in which a chemical that produces a precipitate is added to the crude sugar solution obtained in the dissolution step 2, and impurities such as suspension and pigment components are adsorbed and precipitated and removed from the precipitate. do. The chemical treatment step 3 involves adding lime and carbon dioxide gas to the raw sugar solution and reacting the two to adsorb and remove the impurities to the calcium carbonate produced, so-called carbonation, or adding lime and phosphoric acid to the raw sugar solution. In addition, there is so-called phosphoric acid clarification, in which the impurities are adsorbed and removed by the calcium phosphate produced by reacting the two, or lime and carbon dioxide are added to the raw sugar solution first, and the impurities are adsorbed by the calcium carbonate produced by reacting the two. Lime and phosphoric acid are then further added (if lime is left in the reaction, only phosphoric acid is added), and the resulting calcium phosphate is carbonated to further adsorb the impurities.
There are various methods such as phosphoric acid clarification complex treatment, but the key is to add a chemical that produces a precipitate or add an adsorbent such as magnesium oxide or diatomaceous earth to adsorb impurities in the raw sugar solution to the precipitate. Any treatment may be used as long as it causes coprecipitation, and the most suitable treatment may be selected depending on the situation. Next, the precipitate generated in the chemical treatment step 3 is filtered, and the filtrate is sent to a decolorization step 4 using a powdered anion exchange resin, and passed through an adsorption tower filled with the powdered anion exchange resin. Liquid to adsorb residual pigment components. In addition, in this decolorization step 4, if the pH of the sugar solution has increased due to the addition of magnesium oxide, etc. in the previous chemical treatment step 3, H
It is also effective to use a powdered cation exchange resin. According to experiments conducted by the present inventors, it is sufficient to pulverize used granular cation exchange resin as the powdered cation exchange resin, and it can also be regenerated at the same time as the powdered anion exchange resin is regenerated as described below. It has been found. The powdered anion exchange resin used in the decolorization step 4 may be a matrix such as a copolymer of sterene and divinylbenzene or a copolymer of acrylic and divinylbenzene, etc., and a quaternary ammonium group, an alkanol group, or a tertiary amine. strongly basic anion exchange resins having ion exchange groups such as strong basic groups, medium basic groups, weak basic groups, etc., secondary amine groups, primary amine groups, polyamine groups, medium basic groups Examples include anion exchange resins and weakly basic anion exchange resins, and their ionic forms include OH, Cl, etc.
Although various salt forms such as SO 4 form and SO ₄ form can be mentioned, Cl form strongly basic anion exchange resin is particularly effective. The particle size of the above powdered anion exchange resin is as follows:
It is preferably 250 μm or less, more preferably 100 μm or less. If the particle size is 250 μm or more, it becomes difficult to remove adsorbed substances, mainly dye components, and it becomes difficult to regenerate.
In addition, if the particle size of the powdered ion exchange resin is 5 μm or less, especially 1.5 μm or less, which has a high risk of leakage, it will be difficult to filter and separate, and there is a risk that the resin will be mixed into the processing solution. be. The method for producing the above powdered anion exchange resin is as follows:
Examples include a method of pulverizing a granular anion exchange resin and a method of industrial synthesis, but pulverization is generally used. In addition, as a method of crushing,
Examples include a pneumatic pulverization method, a freeze pulverization method, a mechanical pulverization method, etc., and it is particularly preferable to use a pneumatic pulverization method or a freeze pulverization method. The above-mentioned pneumatic pulverization method is a method in which the particulate anion exchange resin, which is the raw material, is self-pulverized into fine particles by vibration caused by high-frequency pressure fluctuations caused by high-speed vortex flow of air, and the time required to powder it to 50 μm or less is used. It has the characteristic that it is extremely short (about several seconds). According to this pulverization method, the temperature rise during pulverization is 40℃ or less, so there is no deterioration of the resin due to heat.Another characteristic is that the powder has excellent desorption properties for pigment components and has a large regeneration effect. An anion exchange resin having a similar shape can be obtained. In addition, the above-mentioned freeze-pulverization method involves directly contacting granular anion exchange resin with, for example, liquid nitrogen.
The anion exchange resin is cooled to below .degree. C., and then the cooled anion exchange resin is immediately pulverized using a hammer mill or the like. In addition to the above-mentioned liquid nitrogen, refrigerants that can be used for the above-mentioned cooling include various low-boiling point liquefied gases such as liquid carbon dioxide, liquid oxygen, and liquefied propane. Preferably, liquid nitrogen is used on the surface. In this case as well, a powdered anion exchange resin having a fine particle size and a relatively uniform particle size can be obtained without thermal deterioration. On the other hand, with mechanical pulverization using a ball mill or hammer mill, it is difficult to make the particle size of the pulverized material uniform, and when using the obtained powdered anion exchange resin, it is necessary to use a sieve etc. It is preferable to select and use those with a diameter of ~5 μm. moreover,
In the above-mentioned mechanical pulverization method, the time required for pulverization is long and the temperature rise is large, so there is a risk that the decolorizing performance of the powdered anion exchange resin will be reduced. The heat resistance of anion exchange resins is relatively low. For example, the maximum operating temperature of OH type strongly basic anion exchange resins with quaternary ammonium groups as ion exchange groups is said to be 60℃, and if this temperature is exceeded, Thermal decomposition of the ion exchange groups occurs rapidly. Although the details of the adsorption mechanism of dye components by anion exchange resin are unknown, it is thought that the polarity of the anion exchange resin particle surface is largely involved.
It is undesirable that heat is applied during the grinding. The above-mentioned powdered anion exchange resin has better performance than bone char or granular activated carbon in terms of decolorizing action, and the purpose can be sufficiently achieved by using it in an amount of 0.5% based on the solution. Furthermore, this amount can be significantly reduced by adopting a multi-stage contact method or a powder resin layer method. For example, as shown in FIG. 2, a plurality of powder resin tower columns 11 filled with powdered anion exchange resin, four series in this example, are created, three of which are a three-stage decolorization system, and one column is a three-stage decolorization system. Efficient processing is possible by employing a so-called merry-go-round system in which a regeneration tower is used and regeneration operations are performed sequentially. In this case, the amount of solution purified per unit amount of resin increases significantly, and in particular, in the powder resin layer method, the amount reaches about 10 times that of the conventional method using granular anion exchange resin. In addition,
When creating the powdered resin layer, a powdered anion exchange resin, diatomaceous earth, a fibrous filter aid, etc. may be mixed and used. In addition, when using a powdered anion exchange resin, the liquid to be treated is color index AI (Attenuation
A solution with a high color value (Index) of 100 or higher can decolorize most effectively. Furthermore, the above-mentioned powdered anion exchange resin not only has a higher adsorption amount than the granular anion exchange resin, but also has specificity for polymeric dyes that have absorbance characteristics in the visible high wavelength region of 560 to 720 nm. It was found that the amount of adsorption was large. On the other hand, if the decolorizing ability of the powdered anion exchange resin decreases, in the regeneration step 5, an acid and/or metal ion-containing solution is used as a regenerant,
The solution is brought into contact with this regenerant under stirring, for example in batches, to remove adsorbed substances such as pigment components, regenerated, and used again to decolorize the solution. In some cases, it may be effective to use ultrasonic stirring during the regeneration to improve the separation of colloidal components adhering to the surface of the powdered anion exchange resin. As the acid and/or metal ion-containing solution used as the regenerating agent, acid-containing organic solvents or metal ion-containing organic solvents are effective, and acid-containing acetone, acid-containing methanol, and alkali metal ion-containing methanol are particularly effective. be. In addition, when an organic solvent such as ethanol, ether, chloroform, or hexane is used as the organic solvent, there is also an effect of desorbing the dye component. Further, examples of the acid include hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, formic acid, acetic acid, etc., but it is more effective to use a mineral acid such as hydrochloric acid. Furthermore, although it is effective to use saline, sodium hydroxide-containing saline, hydrochloric acid-containing saline, etc. as the metal ion-containing solution, the regeneration effect thereof is inferior to the acid-containing acetone and the like. Most preferably, it is first brought into contact with an aqueous solution containing an acid and/or a metal ion, and then brought into contact with an organic solvent containing an acid and/or a metal ion. By the way, as for the acid concentration in the acid-containing organic solvent, the desorption rate increases as the concentration increases, but even when the acid concentration increases to 5% or more, the amount of desorption does not increase significantly. Furthermore, when acid-containing acetone was used, no difference was observed in the desorption performance up to a water content of around 50%. When the above powdered anion exchange resin is regenerated using a regenerating agent containing a highly permeable organic solvent such as acetone, the desorption rate is extremely fast, and the adsorption can be performed with just a short period of contact. It is possible to almost completely remove the pigment components, etc. Also,
When an aqueous solution is used as the regenerating agent, it is necessary to use a large amount of the regenerating agent, and the usage conditions must also be high temperature. The amount used can be significantly reduced, and usually 10 to 20 times the amount of powdered anion exchange resin to be regenerated is sufficient.
When using a regenerating agent mainly composed of the above-mentioned organic solvent, the organic solvent used for regeneration can be easily recovered and reused by distillation, etc., and the amount of waste liquid can be reduced. , the benefits are great. Furthermore, when recovering the organic solvent, there is also the effect of facilitating the recovery of valuable substances in the waste liquid. The sucrose solution from which most of the pigment components have been removed in the decolorization step 4 described above is further sent to a purification step 6 using a granular ion exchange resin to remove remaining pigment components, salts, and the like. The granular ion exchange resin used in the above purification step 6 generally has a particle size of 0.3 to 0.6 mm, and its types include strong basic anion exchange resin, weak basic anion exchange resin, and strong acid Examples include acidic cation exchange resins, weakly acidic cation exchange resins, and the like. For example, a reverse method in which the liquid is sequentially passed through a strong basic anion exchange resin column 12, a weak acidic cation exchange resin column 13, and a weak basic anion exchange resin column 14 (usually omitted) as shown in FIG. 4, a mixed tower 15 of a strong basic anion exchange resin and a strong acid cation exchange resin, a strong basic anion exchange resin tower 16, and a weak acid cation exchange resin tower 1 as shown in FIG.
A modified reverse method (MAK system) in which the solution is sequentially passed through 7 is effective for purifying the sucrose solution to a high degree of purity. When the capacity of the granular ion exchange resin decreases, it is regenerated by passing a regenerating agent such as an alkaline solution such as a sodium hydroxide solution, an acid such as hydrochloric acid, or a salt solution such as a sodium chloride solution in the regeneration step 7. However, since the liquid to be treated that is supplied to the purification step 6 has had its pigment components strongly removed by the powdered anion exchange resin in the decolorization step 4, it is possible to reuse it by granular ion exchange. Contamination of the resin can be effectively prevented and the service life can be considerably extended. The sucrose solution can be purified to high purity by going through the above-mentioned decolorization step 4 and purification step 6,
Fine liquor is obtained. According to the method described above, it is possible to simplify the equipment, reduce the running cost of auxiliary materials such as washing water, and simplify operation management, and the liquid flow rate is also 10 times more than that of a conventional system. The economic effect is great because it can be done. By the way, the capacity of the granular ion exchange resin used in the purification step 6 gradually decreases with long-term use, and eventually it becomes impossible to restore sufficient performance even through regeneration. In this case, the used particulate ion exchange resin is generally disposed of as industrial waste, but in the present invention it is possible to reuse it. That is, as shown in FIG. 5, the granular ion exchange resin that has become unusable in the purification step 6 is pulverized in the pulverization step 8, and is further regenerated by being brought into contact with a regeneration agent in the regeneration step 9. It can be used as a powdered ion exchange resin of No. 4. Examples of the method for pulverizing the granular ion exchange resin include the air flow pulverization method and freeze pulverization method as described above, and the regeneration agent used in the regeneration step 9 includes the regeneration of the powdered anion exchange resin described above. An acid and/or metal ion-containing solution may be used in the same manner as the regenerating agent that is sometimes used. Through the above-mentioned pulverization process 8 and regeneration process 9, the adsorbed substances accumulated in the resin pores of the used granular ion exchange resin, especially colloidal components containing polymeric dyes and heavy metals, are easily removed, leaving the powder as good as new. An ion exchange resin with a shape of In this way, in the present invention, the used particulate ion exchange resin, which should originally be discarded, can be reused as if it were new in the decolorization process 4, which is a pretreatment process, and these decolorization process 4 and purification process 6 When considered as a series of systems, the economic benefits are extremely large. Furthermore, in the present invention, it is even possible to reuse the regeneration waste liquid used for regenerating the granular ion exchange resin in the purification step 6. That is, as shown in FIG. 6, the recycled waste liquid used for regenerating the granular ion-exchange resin in the purification step 6 is hardly contaminated even after the granular ion-exchange resin is treated with the sucrose solution.
It is sufficiently durable to be used as a regenerating agent for powdered anion exchange resins, and can be reused. Therefore, it is advantageous not only economically, but also in terms of water treatment, etc., since the amount of waste liquid is reduced. Next, specific examples will be described in order to make the present invention more clear, but it goes without saying that the present invention is not limited to these examples. Example 1 1 g of powdered anion exchange resin (moisture 51.5%) made from granular anion exchange resin used in a sugar refinery by air pulverization to 50 μm or less (average particle size 18.5 μm) and 2 to 2 g of glass wool.
A powdered resin column was prepared by mixing the mixture with 05 g of a super-aid agent cut into 5 mm lengths and filling the mixture into a column with a diameter of 2 cm and a height of 10 cm. Four series of the above powdered resin columns were created, and the three towers constituted a three-stage decolorization system using a merry-go-round system, and the effluent from the carbonation process was produced at 40 ml per hour.
On the other hand, the remaining column is used as a regeneration column and is supplied with 20 ml of 80% acetone water containing 5% HCl per hour for every 500 ml of throughput of the above powder resin column.
Pour water at a rate of 40ml and add 40ml of water per hour.
Regeneration operation was carried out by washing by passing liquid at a rate of 80 ml. The time required for reproduction was approximately 1 hour. Next, the sucrose solution treated with the three-stage decolorization system was transferred to an M column, which was mixed and filled with 20 ml of a hydroxyl group-type strongly basic anion exchange resin and 10 ml of a Na-type strongly acidic cation exchange resin. A tower filled with 10ml of ion exchange resin, weakly acidic cation exchange resin
The improved reverse purification process consists of a K column packed with 20 ml of 40 ml per hour at a temperature of 50°C.
It passed at a rate of . Table 1 shows the quality of the sucrose solution in each step.

[Table] In this example, the throughput of the sucrose solution of the powdered anion exchange resin reached 500 times the resin volume, and the liquid passing rate was extremely high at SV (space velocity) 40, compared to that of the normal system. Comparison revealed that both values were more than 10 times higher. Example 2 Raw sugar (produced in the Philippines, ash content 0.45%, color value rb
6500, invert sugar RS 0.7%) was dissolved in water, a carbonation saturation method was performed, and a clear liquid was obtained by filtration. This clear liquid is designated as BL. Add 10g of powdered anion exchange resin (water 51.5%) and powdered weakly acidic cation exchange resin (H type, moisture) to the clarified liquid BL1 to remove alkaline components.
Add 10g of 47%) and stir the reaction at 70℃ for 30 minutes, then separate using paper (No. 2) and remove the liquid CL.
-1 was obtained. Next, this liquid CL-1 was passed at SV40 through a powdered resin column in which 2 g of powdered anion exchange resin (water content 51.5%) was mixed with glass wool and packed into a column with a diameter of 2 cm and a height of 10 cm. Processed sugar solution CL-2
I got it. In addition, OH type strong basic anion exchange resin,
The above-mentioned treated sugar solution CL-2 is passed through the improved reverse method purification process using a Na-type strongly acidic cation exchange resin and an H-type weakly acidic cation exchange resin.
Purification was carried out by passing through the solution to determine the point at which the value was 10 μΩ/cm. This treated sugar solution was named CL-3. In addition, the powdered anion exchange resin added to the clarified liquid BL was able to desorb most of the adsorbed dye by contact treatment with the regenerated waste liquid (BaCl-containing HCl and NaCl-containing NaOH solution) of the improved reverse purification process. , an additional 5% to make the playback operation more complete.
Contact treatment was performed using 50 ml of an acetone solution containing HCl.
In addition, through this regeneration operation, the powdery weakly acidic cation exchange resin was also ion-exchanged into the H form, making it possible to reuse it. Table 2 shows the quality of each sugar solution when used repeatedly for 5 cycles.

【table】 [Brief explanation of the drawing]

FIG. 1 is a flowchart showing an example of an embodiment of the present invention, FIG. 2 is a schematic diagram showing an example of a specific configuration of the decolorization process, and FIG. 3 is a schematic diagram showing an example of a specific configuration of the purification process. , FIG. 4 is a schematic diagram showing another example of the purification process. FIG. 5 is a flowchart showing another example of the embodiment of the present invention, and FIG. 6 is a flowchart showing still another example.

Claims (1)

[Scope of Claims] 1. A decoloring step in which a sucrose solution is brought into contact with a powdered anion exchange resin to remove adsorbed substances, mainly dyes, and a granular ion exchange resin mainly composed of a strongly basic anion exchange resin. The powdered anion exchange resin used in the decolorization step is regenerated by contacting with an acid and/or metal ion-containing solution to desorb the adsorbed substance, and can be used repeatedly. Characteristic method for purifying sucrose solution. 2. A decolorization step in which the sucrose solution is brought into contact with a powdered anion exchange resin to remove adsorbed substances, mainly dyes, and a purification step in which the sucrose solution is brought into contact with a granular ion exchange resin mainly composed of a strongly basic anion exchange resin. The powdered anion exchange resin used in the decolorization process is a powdered anion exchange resin manufactured by crushing the granular ion exchange resin used in the purification process, and this powdered anion exchange resin is and/or a method for purifying a sucrose solution, characterized in that it is regenerated and used repeatedly by bringing it into contact with a metal ion-containing solution to desorb an adsorbed substance. 3. A decolorization step in which the sucrose solution is brought into contact with a powdered anion exchange resin to remove adsorbed substances, mainly dyes, and a purification step in which the sucrose solution is brought into contact with a granular ion exchange resin mainly composed of a strongly basic anion exchange resin. The powdered anion exchange resin used in the decolorization process is a powdered anion exchange resin manufactured by crushing the granular ion exchange resin used in the purification process, and the powdered anion exchange resin is A method for purifying a sucrose solution, characterized in that it is regenerated and used repeatedly by bringing it into contact with a regenerated waste liquid of a granular ion exchange resin used in a refining process to desorb adsorbed substances.