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A refining and purification process for the bottom liquid of the three-effect evaporation distillation after separation and hydrogenation in the production process of caprolactam

A caprolactam, three-effect evaporation technology, applied in the separation/purification of lactam, organic chemistry, chemical instruments and methods, etc., can solve the problems of caprolactam unstable quality, low pass rate, and different quality, and achieve high pass rate , stable quality and high purity

Active Publication Date: 2020-07-28
河北美邦工程科技股份有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to address the deficiencies of the existing process, to provide a refining and purification process for the bottom liquid of the three-effect evaporation and distillation after the separation and hydrogenation of caprolactam in the production process, so as to solve the problems caused by the recycling of the bottom liquid in the existing process. The quality of caprolactam is unstable, the pass rate is low, and the quality is different

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  • A refining and purification process for the bottom liquid of the three-effect evaporation distillation after separation and hydrogenation in the production process of caprolactam

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Embodiment 1

[0027] The technological process reference of this embodiment figure 1 .

[0028] (1) Three-effect evaporative distillation tank bottom liquid water-soluble cooling crystallization

[0029] In the production process of caprolactam, after separation and hydrogenation, the temperature of the bottom liquid of the three-effect evaporation distillation is lowered to 80°C, and then 80°C pure water with 10% of the mass of the bottom liquid is added to completely dissolve the caprolactam in the bottom liquid in pure water , to obtain caprolactam aqueous solution; the obtained caprolactam aqueous solution is pretreated by membrane filtration to remove solid impurities, and then cooling crystallization is carried out. The condition is to cool down to 10°C at a rate of 5°C / h, then keep warm for 30min, and stir during cooling and heat preservation. The speed is 45rpm to obtain the caprolactam crystallization liquid; the obtained caprolactam crystallization liquid is centrifuged to obtain...

Embodiment 2

[0043] (1) Three-effect evaporative distillation tank bottom liquid water-soluble cooling crystallization

[0044] In the production process of caprolactam, the temperature of the three-effect distillation bottom liquid after separation and hydrogenation is lowered to 85°C, and pure water with a mass of 13% of the bottom liquid and a temperature of 85°C is added to completely dissolve the caprolactam in the bottom liquid in the caprolactam production process. The aqueous solution of caprolactam is obtained in pure water, and the aqueous solution of caprolactam is pretreated by membrane filtration to remove solid impurities, and then the crystallization is carried out at a cooling gradient of 6°C / h, the temperature is lowered to 13°C, and the temperature is kept for 35 minutes. During the cooling and heat preservation process, the stirring speed is 55rpm, obtain the caprolactam crystallization liquid, then carry out centrifugation to obtain a centrifuged mother liquor and caprol...

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Abstract

The invention discloses a hybridized and hydrogenated triple-effect evaporation distillation still base solution refining and purifying technology in a caprolactam production process. The technology can be used for preparing caprolactam solid products and nylon chip products by the work procedures: performing water-soluble cooling crystallization on a hybridized and hydrogenated triple-effect evaporation distillation still base solution, evaporating and recrystallizing, treating caprolactam crystal and the like. The method disclosed by the invention utilizes a cooling crystallization and evaporation distillation integrated technology to refine the triple-effect evaporation distillation still base solution and remove trace impurities in the still base solution, so that impurity accumulationcaused by mechanical application of the still base solution is avoided, a caprolactam finished product has stable quality, high yield and high purity, and product quality of final products of the caprolactam solid products and the caprolactam solid products can reach a standard of national-standard superior products; a water content in an intermediate product of the caprolactam crystal is about 0.5 to 2%, other indexes of the intermediate product all can reach the standard of the national-standard superior products, a product quality standard requirement of caprolactam required by downstreamhigh-speed spinning production is met, and the intermediate product can be directly prepared into the nylon chip products.

Description

technical field [0001] The invention relates to a method for refining and purifying caprolactam, a raw material for caprolactam, and specifically provides a process for refining and purifying the bottom liquid of a three-effect evaporation and distillation tank in the production process of caprolactam after separation and hydrogenation. Background technique [0002] Caprolactam is an important organic chemical raw material. Its main purpose is to produce polyamide chips through polymerization, which can be further processed into nylon fibers, engineering plastics, etc., and can also be used in coatings, plastic agents, and a small amount of synthetic lysine . At present, about 90% of polyamides are used to produce synthetic fibers, that is, Capron, and 10% are used as plastics for the manufacture of gears, bearings, pipes, medical equipment, electrical, and insulating materials. [0003] At present, about 90% of caprolactam in the world is prepared from cyclohexanone oxime ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D223/10C07D201/16C08G69/16C08G69/14
CPCC07D201/16C07D223/10C08G69/14C08G69/16
Inventor 金作宏刘东卢远峰南向竹闫利军魏朝帅刘永英李彦新赵途王素霞王莉
Owner 河北美邦工程科技股份有限公司