JPS6242659B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for regenerating a chlorine-type strongly basic anion exchange resin (hereinafter simply referred to as Cl-RIE) used for decolorizing and purifying a sugar solution. Conventionally, Cl-RIE has been used to decolorize and purify sucrose aqueous solutions, beet sugar aqueous solutions, glucose aqueous solutions, fructose aqueous solutions, mixed sugar solutions of these sugars (hereinafter simply referred to as sugar solutions), glycerin aqueous solutions, etc. The method for regenerating the Cl-RIE used for this decolorization and purification is to elute the adsorbed colored substances and organic acids by treating it with an aqueous sodium chloride solution, and at the same time to elute it with a strong basic anion exchange resin (hereinafter simply referred to as RIE). A chlorine type method is adopted. In this method, the colored substance adsorbed on RIE is not completely eluted, and the adsorption capacity gradually decreases. For RIE whose adsorption capacity has decreased in this way, methods of regenerating it with a mixed aqueous solution of sodium chloride and sodium hydroxide, a method of first treating it with an aqueous sodium hydroxide solution and then treating it with sodium chloride, etc. are adopted. However, the technology to completely elute the adsorbed colored substances has not yet been perfected. For RIE whose adsorption capacity cannot be recovered even with the treatment methods described above, a so-called regeneration method is adopted in which the adsorption capacity is restored by decomposing the colored substance through oxidation treatment using sodium hypochlorite, etc. This oxidation treatment with sodium hypochlorite oxidizes not only the colored substance but also the RIE itself, which has the disadvantage of shortening the life of the RIE. The present inventor is able to adsorb and elute colored substances in sugar solution over a long period of time without using oxidizing agents such as sodium hypochlorite as much as possible.
The present invention was completed after studying a method for regenerating Cl-RIE. That is, in the present invention, a sugar solution is passed through a chlorine-type strongly basic anion exchange resin, colored substances in the sugar solution are adsorbed, and the anion exchange resin, which has a reduced ability to adsorb colored substances, is chlorinated. The gist of this invention is a method for regenerating a strongly basic anion exchange resin, which is characterized by regenerating it by passing an aqueous calcium solution through it. The present invention will be explained in detail below. The concentration and amount of the calcium chloride aqueous solution used as a regenerating agent in the present invention vary depending on the nature and amount of the coloring substance, but the concentration of the calcium chloride aqueous solution is effective from a concentration as low as about 1% by weight.
Potency increases with increasing concentration. However, if sulfate ions are present in the sugar solution to be decolorized and purified, calcium sulfate will precipitate.
It can be regenerated with a calcium chloride aqueous solution of about 10% by weight. Furthermore, the higher the temperature during regeneration, the better the elution effect of the colored substance, but the effect is usually greater when the regenerant temperature is around 70° C., which is the heat-resistant temperature of RIE. In the method of the present invention, a sugar solution is passed through Cl-RIE, and a calcium chloride aqueous solution is passed through the RIE whose ability to adsorb colored substances has decreased to elute colored substances, and the RIE is chlorinated to Cl-RIE. - Although the invention is for regeneration as RIE, each time RIE that has adsorbed a colored substance is regenerated, regeneration with a calcium chloride aqueous solution may be performed, or normal regeneration is performed with a sodium chloride aqueous solution, and regeneration is performed with sodium chloride.
RIEs whose capacity has not been completely restored may be regenerated by the method of the present invention, that is, by using an aqueous calcium chloride solution. Also, when performing the regeneration of the present invention, regeneration may be performed using a mixed aqueous solution of calcium chloride and sodium hydroxide. Although it is not clear why an aqueous calcium chloride solution is effective in regenerating the ion exchange resin used for decolorizing and purifying sugar solutions, the method of the present invention enables the use of aqueous sodium chloride solutions or sodium chloride and water that have been used in the past. Compared to regeneration using a mixed solution of sodium oxide, impurities such as pigments and other organic substances adsorbed in the resin pores can be eluted more effectively, so treatment with sodium hypochlorite is not necessary. Therefore, operation management becomes very easy. Next, the present invention will be specifically explained using examples. Example 1 A glass column with a jacket of 20 mm inner diameter and 1000 mm height was coated with a strong basic anion exchange resin Diaion.
SA11A (manufactured and sold by Mitsubishi Chemical Industries, Ltd.)
It was filled with 150 ml and 200 ml of 7% calcium chloride solution was passed through it to convert the resin into Cl type. Aqueous sucrose solution (solid content, Brix 70) 7 after carbonation treatment was passed through this Cl-RIE tower while maintaining the temperature at 65°C, and after washing with 750ml of demineralized water, a 7% calcium chloride solution at 70°C was added as a regenerating agent. SV5hr ^-1 using 200ml
The RIE tower was regenerated. Next, 30 cycles of passing the sucrose solution and regenerating were performed.
The amount of dye released from the regenerated waste liquid at the 31st cycle was measured. Similar experiments were conducted under the same conditions as above when sodium chloride was used as the regenerant. The results are shown in Table 1.

[Table] In Table 1, the amount of dye released is compared with the amount of dye released in sodium chloride as 100. Example 2 Strongly basic anion exchange resin Diaion was placed in a jacketed glass column with an inner diameter of 20 mm and a height of 1000 mm.
SA11A (manufactured and sold by Mitsubishi Chemical Industries, Ltd.)
It was filled with 150 ml and 200 c.c. of 10% saline solution was passed through it to make the filled resin into Cl type. A sucrose aqueous solution (solid content, Brix 70) 7 after carbonation saturation treatment was passed through this Cl-RIE tower while maintaining it at 65°C, washed with water, and regenerated using 200 ml of a 10% sodium chloride aqueous solution at 70°C. Washed with water. This operation
After repeating 30 cycles, the 31st cycle was completed with the sugar solution in step 7 passed through and washed with water. Note that the sodium chloride aqueous solution and the sucrose solution were passed at a rate of SV=5 hr ^-1 . Next, this resin was taken out from the column, and after thoroughly mixing the resins in the upper and lower parts of the column, the resin was packed into six columns similar to the glass columns used above. To this resin, 20 ml of calcium chloride aqueous solution of various concentrations was added at SV = 5 hr ^-1 while maintaining each temperature listed in Table 2.
The amount of eluted dye in the effluent was measured. A similar test was conducted on 20 ml of sodium chloride aqueous solution at each temperature and concentration listed in Table 2, and a mixed solution of 10 ml of sodium chloride aqueous solution at each temperature and concentration listed in Table 2 and 10 ml of 10% sodium hydroxide aqueous solution. Ta.

[Table] In Table 2, the amount of eluted dye is based on the amount of eluted dye at 20°C in a 10% sodium chloride aqueous solution.
This was set as 100 and displayed for comparison. As is clear from these results, it is understood that when the calcium chloride of the present invention is used as a regenerating agent, the dye elution effect is extremely good. Furthermore, it is understood that the effect is further improved by increasing the temperature of the regenerant.

Claims (1)

[Scope of Claims] 1. A sugar solution is passed through a chlorine-type strongly basic anion exchange resin to adsorb colored substances in the sugar solution, and the anion exchange resin has a reduced ability to adsorb colored substances. A method for regenerating a strongly basic anion exchange resin, the method comprising regenerating a strongly basic anion exchange resin by passing an aqueous calcium chloride solution through the resin. 2. The method for regenerating a strongly basic anion exchange resin according to claim 1, wherein the calcium chloride aqueous solution is an aqueous solution containing 5 to 10% by weight of calcium chloride.