System and process for recovering dimethylacetamide from cefuroxime axetil production waste liquor

Abstract

The invention discloses a recovery system and process for dimethylacetamide in cefuroxime axetil production waste liquid. After the equipment processes such as dehydration distillation tower and rectification kettle are processed, a large amount of ethyl acetate, isopropanol and other low boiling point substances are reclaimed from the mother liquor, DMAC, water and impurities are successfully separated, and qualified DMAC products are reclaimed. The present invention has the advantages of : Increase the pressure of the first-stage dehydration distillation tower, increase the temperature at the bottom of the tower and the steam space of the evaporation tank, thereby expanding the temperature difference and pressure difference between the evaporation tank and the evaporation tank, so that the residual liquid of the high-temperature and high-pressure autoclave is directly pressed into the V by the pressure difference 1. The evaporation tank has a good flash evaporation effect and reduces pump equipment; the reboiler is used for circulating flash evaporation to speed up the solid-liquid separation speed; efficiently recycles the DMAC.

Description

technical field [0001] The invention relates to the technical field of recycling cefuroxime axetil production waste liquid, in particular to the recovery technology of dimethylacetamide in cefuroxime axetil production waste liquid. Background technique [0002] Because DMAC is an excellent chemical solvent, it can be widely used in the manufacturing industries such as pharmaceuticals and pesticides. When it participates in production, it also brings about the problem of waste liquid containing a large amount of DMAC. [0003] While DMAC is used as a chemical solvent, it can also be used as a bacteriostatic agent because of its characteristics. Activated sludge is easily killed by DMAC, so the waste liquid cannot be treated by biochemical treatment methods. Distillation is a commonly used recovery method, but different schemes still have different problems. [0004] In China, the invention patent application publication number is "CN10489484A". The publication date of the ap...

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Problems solved by technology

[0012] 1. The working temperature of the fourth concentration tower makes the material entering the flash tank low temperature and low pressure, which not only needs to increase the cost of pump equipment to add materials into the flash tank, but also affects the flash evaporation effect;

[0013] 2. After the flash tank is flashed, only the gas phase is recovered and treated, and there is no relevant follow-up treatment technology for the liquid material, which wastes resources in the liquid and the recovery efficiency is not high;

[0020] 1. The dehydration distillation tower uses atmospheric pressure for dehydration. Because the wastewater becomes thicker after distillation, the temperature at the bottom of the tower needs to be 103-105°C to distill water, and the distillation is slow, time-consuming and energy-consuming;

[0021] 2. When the residual liquid in the kettle is pumped to the evaporation tank, a good flash evaporation effect cannot be formed, and the reboiler is not used for circulating flash evaporation, resulting in time-consuming distillation, slow solid-liquid separation, high energy consumption, and an additional 1 to 2 pumps;

[0022] 3. Plate-and-frame filter press is used for salt removal. Because the distillate is viscous, it is difficult to filter, and the filter pressure is not clean. Part of the DMAC is carried out by the salt, resulting in a decrease in yield and difficult follow-up treatment of the salt.

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