阅读说明：本技术 一种维生素c生产母液的处理工艺 (Treatment process of vitamin C production mother liquor ) 是由 徐翔 徐建涛 于 2019-09-25 设计创作，主要内容包括：本发明涉及一种母液的处理工艺,具体涉及一种维生素C生产母液的处理工艺。包括以下步骤：(1)将维生素C生产母液用稀硫酸调溶液pH值至1.5-2.5,然后浓缩至膏状；(2)检测浓膏状浓缩液的含水量、古龙酸及维生素C的含量；(3)加入无水硫酸钠,搅拌均匀；加入无水甲醇萃取；(4)冷冻,静置；(5)抽滤,加入活性炭脱色；(6)加入浓硫酸；(7)甲酯化反应,加入碳酸钠或碳酸氢钠,内酯化反应,冷却,过滤,得维生素C钠盐粗品。本发明工艺,处理成本低,能够接收前道三种母液以及自身母液,易于实现自动化,有效成分(古龙酸和维生素C)的回收率高、纯度高,提高了经济效益。(The invention relates to a treatment process of mother liquor, in particular to a treatment process of mother liquor for producing vitamin C. The method comprises the following steps: (1) adjusting the pH value of the vitamin C production mother liquor to 1.5-2.5 by using dilute sulfuric acid, and then concentrating the solution into paste; (2) detecting the water content of the concentrated pasty liquid and the content of gulonic acid and vitamin C; (3) adding anhydrous sodium sulfate, and stirring; adding anhydrous methanol for extraction; (4) freezing and standing; (5) performing suction filtration, and adding active carbon for decoloring; (6) adding concentrated sulfuric acid; (7) methyl esterification, adding sodium carbonate or sodium bicarbonate, lactonization, cooling, and filtering to obtain vitamin C sodium salt crude product. The process has low treatment cost, can receive the three former mother liquors and the mother liquor, is easy to realize automation, has high recovery rate and high purity of the effective components (gulonic acid and vitamin C), and improves economic benefit.)

1. A treatment process of vitamin C production mother liquor is characterized in that: the method comprises the following steps:

(1) regulating the pH value of the vitamin C production mother liquor to 1.5-2.5 by using dilute sulfuric acid, and then carrying out reduced pressure evaporation and concentration to obtain a concentrated paste;

(2) detecting the water content of the concentrated pasty liquid and the contents of gulonic acid and vitamin C, and calculating the weight of the gulonic acid and the vitamin C;

(3) adding anhydrous sodium sulfate, and stirring; then adding anhydrous methanol and stirring evenly to form suspension, extracting the gulonic acid and the vitamin C in the concentrated solution by using the methanol for 0.5 to 3 hours;

(4) cooling the suspension liquid after extraction to-10-25 deg.C under stirring, maintaining at-10-25 deg.C for 0.5-10 hr, stopping stirring, and standing for 1-10 hr to obtain standing solution;

(5) filtering the standing solution to obtain filtrate, adding active carbon, stirring, heating to 30-55 deg.C, and decolorizing for 0.5-2 hr;

(6) filtering to obtain decolorized filtrate, and adding concentrated sulfuric acid;

(7) performing methyl esterification on the decolored filtrate added with concentrated sulfuric acid at 65-75 ℃ for 1.5-5 hours, then adding sodium carbonate or sodium bicarbonate, performing esterification at 65-75 ℃ for 3 hours, cooling to-5-35 ℃, filtering to obtain a solid substance, namely a crude product of the vitamin C sodium salt.

2. The process for treating vitamin C production mother liquor according to claim 1, wherein: in the step (1), the dilute sulfuric acid is 10-60% of dilute sulfuric acid.

3. The process for treating vitamin C production mother liquor according to claim 1, wherein: in the step (1), the temperature of the reduced pressure evaporation is 30-80 ℃.

4. The process for treating vitamin C production mother liquor according to claim 1, wherein: in the step (3), the dosage of the anhydrous sodium sulfate is 0.2-1 time of the dosage of the substance of water.

5. The process for treating vitamin C production mother liquor according to claim 1, wherein: in the step (3), the amount of the absolute methanol is 3-10 times of the weight of the gulonic acid and the vitamin C.

6. The process for treating vitamin C production mother liquor according to claim 1, wherein: in the step (5), the dosage of the active carbon is 0.01-1% of the mass of the filtrate.

7. The process for treating vitamin C production mother liquor according to claim 1, wherein: in the step (6), the concentrated sulfuric acid is 98% concentrated sulfuric acid, and the dosage of the concentrated sulfuric acid is 1-3% of the weight of the gulonic acid and the vitamin C.

8. The process for treating vitamin C production mother liquor according to claim 1, wherein: in the step (7), the amount of the sodium carbonate is 0.5 time of the amount of the substances of the gulonic acid and the vitamin C.

9. The process for treating vitamin C production mother liquor according to claim 1, wherein: in the step (7), the dosage of the sodium bicarbonate is 0.95 to 1.1 times of the dosage of the substances of the gulonic acid and the vitamin C.

Technical Field

The invention relates to a treatment process of mother liquor, in particular to a treatment process of mother liquor for producing vitamin C.

Background

Three colloidal mother solutions are generated in the production process of the vitamin C, namely, the gulonic acid is extracted for a plurality of times, the vitamin C is converted for a plurality of times, and the refined vitamin C is refined for a plurality of times. The three mother liquors are enriched with a large amount of colloidal impurities after being subjected to multiple evaporation processes, and active ingredients (mainly gulonic acid and vitamin C) in the three mother liquors can not be extracted, so that the three mother liquors are taken as wastes in the industry and discharged after being subjected to environment-friendly biochemical treatment, but the three mother liquors contain a large amount of active ingredients and cause great economic loss after being discarded. How to extract the effective components in the mother liquor has become an important research topic in the field.

CN101041649A discloses a production method for recovering vitamin C and gulonic acid from vitamin C mother liquor. The method comprises the following steps: (1) diluting the vitamin C mother liquor to be recovered and separated with water; (2) pumping the diluted vitamin C mother liquor into an adsorption column filled with anion exchange resin, adding water to wash the adsorption column after adsorption is finished, and collecting effluent liquid; (3) evaporating, concentrating and crystallizing the vitamin C mother liquor which is subjected to adsorption separation and decoloration by a film to obtain vitamin C crystals; (4) eluting the anion exchange resin after adsorption by dilute sulfuric acid, and recovering gulonic acid in the desorption solution to be used as a raw material for producing vitamin C; (5) and desorbing with dilute sulfuric acid, washing with an anion exchange resin column until the pH value is 4-5, leaching with an aqueous solution of sodium hydroxide, finally washing with water until the pH value is 8-9, and recycling after the anion exchange resin is regenerated. The method has good separation effect, but has the problems of long process flow, large energy consumption, high cost and the like.

CN102267962A discloses a novel method for recovering vitamin C from vitamin C secondary mother liquor, which comprises the following steps: a. concentrating the second mother liquor to be viscous; b. adding 99.5% methanol, and stirring; c. adding concentrated sulfuric acid with 3-8 per mill of the total volume of methanol into the mixture to perform esterification reaction at 60-65 ℃; d. dehydrating the water-bearing methanol steam generated in the esterification reaction process through a rectifying tower, and returning the dehydrated methanol to the esterification reaction tank for reuse; e. adding sodium bicarbonate into the transesterification reaction tank, and carrying out a conversion reaction for 5-7 hours; f. after the conversion reaction is finished, cooling to room temperature, and performing centrifugal separation to obtain a Vc-Na crude product. The method has high recovery rate, low cost and simple process. However, there are the following problems:

(1) the application range of the method is limited by two mother solutions of vitamin C. Because the sodium salt of gulonic acid can not be methyl esterified, the process can not realize the combination treatment of the gulonic acid extracted multiple mother liquor, the vitamin C multiple mother liquor in the conversion process and the vitamin C refined process which are formed in the vitamin C production process. In addition, the mother liquor generated by the method cannot be directly returned to a recovery production line designed according to the method to continuously recover the vitamin C. In other words, the improvement of vitamin yield in this method is still limited by the degree of single esterification, and the innovation point is that one additional esterification is performed. Multiple recovery of the mother liquor is limited by the investment economy in the project and eventually cannot be continued when the economics of equipment and energy input are negative.

(2) The degree of esterification reaction mentioned in the point (1) depends on the water removal from the system. And the more the mother liquor is recovered, the poorer the concentratability of the mother liquor is, namely, the viscous mother liquor which is recovered for many times is dehydrated reliably and efficiently in short of means in engineering. The esterification process needs to consume energy to separate the moisture which is not removed from the mother liquor from the reaction system, the reaction is pushed to the direction of generating vitamin C, the concentrated moisture which is not removed is far more than the moisture generated by the esterification reaction, and the steam used for rectification is mainly used for removing the concentrated residual moisture. The distillation consumes much steam, so that the method is relatively energy-saving.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the processing technology for the mother liquor produced by the vitamin C can receive the three former mother liquors and the mother liquor, is easy to realize automation, low in processing cost, high in recovery rate and purity of effective components (gulonic acid and the vitamin C), and improves economic benefits.

The treatment process of the vitamin C production mother liquor comprises the following steps:

(1) regulating the pH value of the vitamin C production mother liquor to 1.5-2.5 by using dilute sulfuric acid, and then carrying out reduced pressure evaporation and concentration to obtain a concentrated paste;

(2) detecting the water content of the concentrated pasty liquid and the contents of gulonic acid and vitamin C, and calculating the weight of the gulonic acid and the vitamin C;

(3) adding anhydrous sodium sulfate, and stirring; then adding anhydrous methanol and stirring evenly to form suspension, extracting the gulonic acid and the vitamin C in the concentrated solution by using the methanol for 0.5 to 3 hours;

(4) cooling the suspension liquid after extraction to-10-25 deg.C under stirring, maintaining at-10-25 deg.C for 0.5-10 hr, stopping stirring, and standing for 1-10 hr to obtain standing solution;

(5) filtering the standing solution to obtain filtrate, adding active carbon, stirring, heating to 30-55 deg.C, and decolorizing for 0.5-2 hr;

(6) filtering to obtain decolorized filtrate, and adding concentrated sulfuric acid;

(7) performing methyl esterification on the decolored filtrate added with concentrated sulfuric acid at 65-75 ℃ for 1.5-5 hours, then adding sodium carbonate or sodium bicarbonate, performing esterification at 65-75 ℃ for 3 hours, cooling to-5-35 ℃, filtering to obtain a solid substance, namely a crude product of the vitamin C sodium salt.

Wherein:

in the step (1), the vitamin C production mother liquor is a mixed liquor of a mother liquor obtained by extracting gulonic acid for multiple times, a mother liquor obtained by converting vitamin C for multiple times and a mother liquor obtained by refining vitamin C for multiple times.

In the step (1), the dilute sulfuric acid is 10-60% of dilute sulfuric acid.

In the step (1), the temperature of the reduced pressure evaporation is 30-80 ℃.

In the step (3), the dosage of the anhydrous sodium sulfate is 0.2-1 time of the dosage of the substance of water.

In the step (3), the amount of the absolute methanol is 3-10 times of the weight of the gulonic acid and the vitamin C.

In the step (5), the dosage of the active carbon is 0.01-1% of the mass of the filtrate.

In the step (6), the concentrated sulfuric acid is 98% concentrated sulfuric acid, and the dosage of the concentrated sulfuric acid is 1-3% of the weight of the gulonic acid and the vitamin C.

In the step (7), when sodium carbonate is adopted, the amount of the sodium carbonate is 0.5 time of the amount of substances of the gulonic acid and the vitamin C; when sodium bicarbonate is used, the amount of sodium bicarbonate is 0.95-1.1 times of the amount of gulonic acid and vitamin C.

And (7) cooling to-5-35 ℃, filtering to obtain filtrate, feeding the filtrate into a methanol recovery system, and recycling the methanol.

The sodium salt crude product of vitamin C recovered by the invention can be used for the subsequent production of vitamin C.

The invention has the following beneficial effects:

1. the treatment process can receive the former three mother solutions and the mother solution per se, is easy to realize automation, has low treatment cost, high recovery rate (more than 90 percent of single feeding and discharging) and high purity (more than 90 percent) of the effective components (gulonic acid and vitamin C), and improves the economic benefit.

2. The treatment process disclosed by the invention is good in environmental protection. Mirabilite can be reused after being prepared into anhydrous sodium sulfate, and a part of by-products are formed. The whole process has no gulonic acid loss, and reduces the cost of environmental protection treatment.

Drawings

FIG. 1 is a process flow diagram of the process of the present invention.

Detailed Description

The present invention is further illustrated by, but is not limited to, the following examples.