CN108191929B - Sucralose-6-ethyl ester wastewater treatment method - Google Patents

Abstract

The invention relates to a method for treating sucralose-6-ethyl ester wastewater, which comprises the following steps: a. washing water obtained after mother liquor washing is fed into an impurity extraction kettle, ethyl acetate is added for extraction and impurity removal, an impurity extraction water phase and an impurity removed ester phase are obtained, and the impurity removed ester phase is returned to a single-effect concentration working section for use; b. adding crude ester heavy-duty mother liquor into the extraction impurity water phase, mixing, separating to obtain a water phase, returning the water phase to a concentrated dry liquor neutralizing section for use, separating to obtain a sugar-extracted ester phase, continuously performing single-effect concentration and filter pressing, obtaining a sucralose-6-ethyl ester secondary crude product and a secondary crude product mother liquor after filter pressing, returning the sucralose-6-ethyl ester secondary crude product to the crude ester heavy-duty section for use, and returning the secondary crude product mother liquor to the mother liquor concentrated dry section for use continuously. The invention has the advantages that: the product yield can be improved by removing impurities as much as possible, the content of the sucralose-6-ethyl ester reaches more than 99 percent, the quality of the sucralose product is greatly improved, and the washing water can be recycled to reduce the discharge capacity.

Description

Sucralose-6-ethyl ester wastewater treatment method

Technical Field

The invention relates to the field of food additive production, relates to a sucralose production process, and particularly relates to a sucralose-6-ethyl ester wastewater treatment method.

Background

Sucralose is a white powdery product, is very soluble in water (the solubility is 28.2g and the temperature is 20 ℃), has the sweetness 600 times that of sucrose, and has pure sweetness. Sucralose belongs to a non-nutritive intense sweetener, is hardly absorbed in a human body, and has zero caloric value. Sucralose has stable properties, is widely applied to various products such as beverages, chewing gums, chocolates and the like instead of sucrose at present, and is one of the more ideal intense sweeteners in the market.

In sucralose production, after chlorination reaction, extraction and purification of sucralose-6-ethyl ester which is an intermediate produced in the reaction are required, a large amount of wastewater is produced in the purification process, and the wastewater contains a small amount of sucralose-6-ethyl ester, organic solvent and the like. In the current industrial production, the waste water generated after purification is directly sent to a sewage station, which causes environmental pollution and resource waste.

Disclosure of Invention

The invention aims to solve the defects in the prior art and provides a method for treating sucralose-6-ethyl ester wastewater, which is characterized in that the sucralose-6-ethyl ester mother liquor washing water is treated to remove impurities as much as possible, so that the washing water is recycled, and the discharge capacity is reduced.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

a method for treating sucralose-6-ethyl ester wastewater comprises the following main production steps: neutralizing concentrated dry liquid, extracting, decolorizing ester phase, concentrating single-effect, crystallizing, filter pressing, recombining crude ester, concentrating and drying mother liquid, and washing the mother liquid; the method is characterized by comprising the following steps:

a. pumping washing water in a washing water phase tank obtained after washing mother liquor into an impurity extraction kettle by using a pump, adding an extracting agent ethyl acetate into the impurity extraction kettle to extract and remove impurities, wherein the washing water: the volume ratio of ethyl acetate is 8: 1, obtaining an extraction impurity water phase and an impurity ester-removed phase, and returning the impurity ester-removed phase to a single-effect concentration working section for continuous use;

b. b, adding crude ester recrystallization mother liquor generated in the ethyl ester recrystallization process from the sucralose-6-ethyl ester crude product into the impurity extraction water phase obtained in the step a, mixing according to the volume ratio of the impurity extraction water phase to the crude ester recrystallization mother liquor = 1.5: 1, returning the water phase obtained by separation after mixing to a concentrated dry liquid neutralizing section for use, and storing the sugar extraction ester phase obtained by separation in an organic phase tank for later use;

c. and (3) sequentially carrying out single-effect concentration and filter pressing on the ester phase after sugar extraction in the organic phase tank to obtain a sucralose-6-ethyl ester secondary crude product and a secondary crude product mother liquor after filter pressing, returning the sucralose-6-ethyl ester secondary crude product to the crude product ester re-crystallization working section for use, and returning the secondary crude product mother liquor to the mother liquor concentrated drying working section for continuous use.

The method has the advantages that the yield of the sucralose can be increased by about 18 tons every year, the discharge amount of the wastewater is reduced by about 4800 tons every year, the purity of the sucralose-6-ethyl ester is improved by nearly 1 percent, the energy is greatly saved, the pollution discharge is reduced, the cost is reduced, and the benefit is increased.

Drawings

FIG. 1 is a schematic diagram of a sucralose-6-ethyl ester wastewater treatment process, wherein an old process is shown in the right half dotted line box, and a new process is shown in the left half solid line box.

Detailed Description

As shown in figure 1, the sucralose-6-ethyl ester wastewater treatment method provided by the invention comprises the following main production steps: neutralizing concentrated dry liquid, extracting, decolorizing ester phase, single-effect concentrating, crystallizing, filter pressing, recombining crude ester, concentrating and drying mother liquid, and washing the mother liquid.

The method comprises the following specific implementation steps:

1) pumping 4000L of washing water obtained by washing the mother liquor into an impurity extraction kettle by using a pump to extract impurities by using the washing water, adding 500L of ethyl acetate serving as an extracting agent into the impurity extraction kettle to perform extraction, stirring for 1 hour, standing for 2 hours, layering to obtain an impurity extraction water phase and an impurity ester removal phase, and returning the impurity ester removal phase to a single-effect concentration working section for continuous use;

2) adding 3000L of crude ester recrystallization mother liquor generated in the ethyl acetate recrystallization process by sucralose-6-ethyl ester into the impurity extraction water phase obtained by layering in the step 1), stirring for 1 hour, standing for 2 hours, returning the water phase obtained by layering to a concentrated solution neutralizing section for use, and storing the sugar extraction ester phase obtained by layering in an organic phase tank for later use;

3) when the ester phase after sugar extraction in the organic phase tank is collected for 3 batches, the organic phase tank is sent to a single-effect concentration kettle for concentration, the temperature of the concentration kettle is controlled to be 40 ℃, the ester phase after sugar extraction is concentrated to 2500L, the ester phase after sugar extraction is sent to a crystallization kettle, after freezing crystallization is carried out for 10 hours at the temperature of 0 ℃, the ester phase after sugar extraction is sent to a plate and frame type filter press for filter pressing, secondary crude sucralose-6-ethyl ester 280Kg and secondary crude product mother liquor are obtained after filter pressing, the secondary crude sucralose-6-ethyl ester is returned to a crude ester recrystallization section for use, and the secondary crude mother liquor is sent to a mother liquor concentration drying section for continuous use.

Claims (1)

1. A method for treating sucralose-6-ethyl ester wastewater comprises the following production steps: neutralizing concentrated dry liquid, extracting, decolorizing ester phase, concentrating single-effect, crystallizing, filter pressing, recombining crude ester, concentrating and drying mother liquid, and washing the mother liquid; the method is characterized by comprising the following steps:

a. pumping washing water in a washing water phase tank obtained after washing mother liquor into an impurity extraction kettle by using a pump, adding an extracting agent ethyl acetate into the impurity extraction kettle to extract and remove impurities, wherein the washing water: the volume ratio of ethyl acetate is 8: 1, obtaining an extraction impurity water phase and an impurity ester-removed phase, and returning the impurity ester-removed phase to a single-effect concentration working section for continuous use;

b. b, adding crude ester recrystallization mother liquor generated in the ethyl ester recrystallization process from the sucralose-6-ethyl ester crude product into the impurity extraction water phase obtained in the step a, mixing according to the volume ratio of the impurity extraction water phase to the crude ester recrystallization mother liquor = 1.5: 1, returning the water phase obtained by separation after mixing to a concentrated dry liquid neutralizing section for use, and storing the sugar extraction ester phase obtained by separation in an organic phase tank for later use;

c. and (3) sequentially carrying out single-effect concentration and filter pressing on the ester phase after sugar extraction in the organic phase tank to obtain a sucralose-6-ethyl ester secondary crude product and a secondary crude product mother liquor after filter pressing, returning the sucralose-6-ethyl ester secondary crude product to the crude product ester re-crystallization working section for use, and returning the secondary crude product mother liquor to the mother liquor concentrated drying working section for continuous use.

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