Method for removing salt in betaine solution

Abstract

The invention discloses a method for removing salt in betaine solution, which comprises the followings steps: firstly removing 70 weight percent of salt in the betaine solution synthesized by taking chloroactic acid, sodium carbonate and trimethylamine as raw materials through concentration; then diluting with water until the mass concentration of the betaine is between 10 and 15 percent; performing a first-stage semi-transparent film nanofiltration on the solution at a temperature of between 60 and 70 DEG C; when the conductivity of the betaine solution reaches between 7,000 and 8,000mu s / cm, diluting the betaine solution again until the mass percentage concentration of the betaine is between 10 and 15 percent; performing a second-stage semi-transparent film nanofiltration on the solution at a temperature of between 50 and 60 DEG C; when the conductivity of the betaine solution reaches between 700 and 800 mu s / cm, finishing the treatment, desalting by a two-stage nanofiltration membrane, and achieving the effect of completely removing the salt, which cannot be achieved in a common concentration process; and performing thickening crystallization to produce betaine crystal containing less than 0.5 percent of salt. The method ensures the production of pure betaine products, saves electricity, and reduces the phenomenon of raw material waste.

Description

technical field [0001] The invention relates to a method for removing salt in betaine solution. technical background [0002] Betaine is a widely used additive at present. It is used in feed, food, cosmetics, medicine, etc. It is synthesized by using sodium chloroacetate and trimethylamine as raw materials, and then concentrated and desalted. Since the aqueous solution of betaine cannot completely remove the salt by ordinary concentration process, the industry mainly uses synthetic betaine hydrochloride as a commodity. At present, in terms of desalination of pure products, there are mainly two methods: alcohol extraction and electrodialysis. figure 1 . For example, Chinese patent 200410103519.9 discloses the "separation method of glycine betaine and salt compounds in aqueous solution", which uses the properties of glycine betaine to easily pass through the semi-permeable membrane dialysis and the special usage of electrodialyzer, finally from glycine betaine and salt compo...

AI Technical Summary

Problems solved by technology

Electrodialysis requires a lot of power consumption, and the process control in the electrodialysis desalination process is quite strict; in the pure alcohol extraction desalination process, the repeated distillation and recovery of the solvent increases the loss of the solvent, and the solvent desalination is impossible. To pure product content above 99%

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