Method of industrial production of lactic acid by employing molecular distillation technology

Abstract

The invention discloses a method of industrial production of lactic acid by employing a molecular distillation technology. The method comprises the following steps of: (A) decoloring material liquid obtained after acidolysis filtration of lactic acid fermentation liquid with active carbon, (B) performing ion exchange on the decolored material liquid, (C) performing falling film evaporation on the material liquid after the ion exchange, (D) performing thin film evaporation on a lactic acid material obtained after the falling film evaporation to allow the mass fraction of water in the material to be less than or equal 2%, and (E) performing molecular distillation on the lactic acid material obtained after the thin film evaporation to form fine lactic acid, namely the target product. Lactic acid produced by the method meets the high-purity requirements and can be directly used for preparing polylactic acid.

Description

technical field [0001] The invention relates to a preparation method of lactic acid, in particular to a method for industrialized production of lactic acid by using molecular distillation technology. Background technique [0002] Molecular distillation is different from traditional distillation, which relies on the separation principle of boiling point difference, but relies on the difference in the mean free path of molecular motion of different substances to achieve separation. When the liquid mixture is heated, light molecules and heavy molecules will escape from the liquid surface and enter the gas phase respectively. Since the free paths of light molecules and heavy molecules are different, the molecules of different substances will move different distances after escaping from the liquid surface; if If the condenser is set at an appropriate distance from the evaporator, the light molecules will reach the condenser and be condensed and discharged, while the heavy molecul...

AI Technical Summary

Problems solved by technology

For enterprises that produce polylactic acid, the food-grade lactic acid directly produced by the multi-effect falling film concentration device cannot be used as a raw material for polylactic acid production due to shortcomings such as insufficient purity and high impurity content.

At present, there is no mature production process for industrialized production of high-purity lactic acid in foreign countries

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