Method for recycling vitamin C secondary mother liquor

Abstract

The invention discloses a method for recycling a vitamin C secondary mother liquor. Vitamin C sodium is prepared from effective components in the vitamin C secondary mother liquor through the steps ofmembrane decoloration, concentration, transesterification and the like, so that the vitamin C secondary mother liquor is recycled; acid-resistant and high-pressure-resistant decoloration membrane equipment is adopted in the method, pigments in the vitamin C secondary mother liquor are effectively removed, and the recycled product quality is improved; methanol is added in the later stage of the concentration step for continuous concentration, the water content of a concentrated material is remarkably reduced through methanol with water, and the ester conversion yield is increased; sulfuric acid is not added into the concentrated material any more, and the original sulfuric acid and other heteroacids in the vitamin C secondary mother liquor are fully utilized to perform catalytic esterification reaction, thereby saving the raw material consumption; closed decolorizing membrane equipment is adopted for decolorizing, secondary mother dry product centrifugal operation is omitted, and the working environment of staff is obviously improved; the recovery rate of effective components is increased, the loss of the effective components is reduced, and the pressure of environment-friendly treatment is also reduced; the transesterification reaction time is shortened, and the production efficiency is improved.

Description

technical field [0001] The invention relates to a method for recycling vitamin C di-mother liquor, and belongs to the technical field of vitamin C production. Background technique [0002] Vitamin C, also known as L-ascorbic acid, is widely used as vitamin drugs, food additives and feed additives. [0003] At present, the industrial production method of vitamin C is mainly to prepare the intermediate 2-keto-L-gulonic acid of vitamin C by a two-step fermentation method, and then make the 2-keto-L-gulonic acid and methanol undergo esterification conversion reaction to obtain vitamin C. Sodium C and sodium vitamin C are exchanged, decolorized, concentrated, crystallized, and filtered to obtain vitamin C. In the production process of vitamin C, the second mother liquor of vitamin C is produced. The second mother liquor of vitamin C contains vitamin C, 2-keto-L-gulonic acid and 2-keto-L-gulonic acid methyl ester and other active ingredients as well as sulfuric acid and oxalic ac...

AI Technical Summary

Problems solved by technology

Although this method improves the quality of the crude sodium vitamin C product, it uses a macroporous resin for decolorization, the mother liquor after decolorization will be diluted, and the amount of steam consumed for concentration will inevitably increase, and the regeneration of the resin not only consumes a large amount of acid and alkali, but also produces a large amount. In addition, the esterification reaction time is long, the time-sharing control of the esterification temperature is complicated, and the conversion and addition of alkali uses sodium bicarbonate, which is not conducive to cost reduction