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A process for removing alkaline impurities in caprolactam refining process

A caprolactam and impurity technology, applied in the field of alkaline impurity removal technology, to achieve the effects of reduced production costs, simple oxidation treatment process, and improved alkalinity pass rate

Active Publication Date: 2021-05-07
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In view of the problems existing in the existing caprolactam refining process, the purpose of the present invention is to provide a process that can effectively reduce the alkaline impurities in the caprolactam product, while other indicators are not affected. The process is simple to operate, low in cost, and meets industrial production Require

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] The caprolactam aqueous solution with a concentration of 28-38% and a temperature of 80-90°C is hydrogenated, and the hydrogenation catalyst in the water solution is removed, and then sent to a three-effect evaporation tower for concentration. The kettle temperature of the first tower of the three-effect evaporation is controlled at 120-130°C, the temperature of the second tower is controlled at 105-115°C, and the temperature of the third tower is controlled at 72-78°C. The concentration of the material evaporated from the three-effect is 90%, concentrated liquid, and then through a series of tubular heaters, the temperature of the material is raised to 125 ° C, and at the same time, pure air at normal temperature is introduced into the inlet of the heater, and the air flow rate and the material flow rate are kept at 1m 3 :1Nm 3 . The material after air oxidation enters the flash separation tank to separate most of the water, the caprolactam concentration reaches over ...

Embodiment 2

[0022] The difference between this embodiment and embodiment 1 is that pure air is added from the three-effect evaporating tower one tower tank, and the remaining control conditions and flow process are unchanged. The concentration of the obtained caprolactam is 99.7%, and its alkalinity is 0.52mg / kg, which is about 20% lower than the original process.

Embodiment 3

[0024] The difference between this embodiment and embodiment 1 is that pure air is added from the second tower of the three-effect evaporator, and the remaining control conditions and flow process are unchanged. The concentration of the obtained caprolactam is 99.7%, and its alkalinity is 0.56mg / kg, which is about 10% lower than the original process.

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Abstract

The invention discloses a process for removing alkaline impurities in the caprolactam refining process. The caprolactam refining process includes the processes of extraction, ion exchange, hydrogenation, evaporation and distillation. Passing oxygen-containing gas and / or adding acidic potassium permanganate solution, heating for oxidation treatment; or passing high-temperature oxygen-containing gas and / or adding high-temperature acidic potassium permanganate solution in caprolactam solution for oxidation treatment; A process for effectively reducing basic impurities in caprolactam products while other indicators are not affected, the process is simple in operation, low in cost, and meets the requirements of industrial production.

Description

technical field [0001] The invention relates to a process for removing alkaline impurities in the caprolactam refining process, in particular to a process for removing alkaline impurities produced in the hydrogenation process of caprolactam impurities, and belongs to the technical field of caprolactam production. Background technique [0002] The caprolactam produced by the ammoximation process contains many kinds of impurities, and these impurities are mainly organic impurities. There are three main sources of impurities: 1. Incomplete conversion of raw materials, such as cyclohexanone and cyclohexanone oxime in the product, 2. By-products produced during the reaction, such as β-hydroxycyclohexanone and adipyl Imine, n-caproamide, etc. 3. The impurities carried in the raw materials are converted into new impurities during the reaction, such as hexanal is converted into hexylamine through ammoximation and Beckmann rearrangement. The traditional caprolactam refining process ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D223/10C07D201/16
CPCC07D201/16C07D223/10
Inventor 李兴栋王雪陈赶王伟
Owner CHINA PETROLEUM & CHEM CORP
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