Neutralized crystallization system and method of preparing caprolactam through caprolactam rearrangement solution

Abstract

The invention discloses neutralized crystallization system and method of preparing caprolactam through caprolactam rearrangement solution. The neutralized crystallization system is characterized in that a feeding mixer is connected with an inlet in the upper part of a neutralized crystallization reactor, an upper-layer organic phase outlet of the neutralized crystallization reactor is connected with an inlet of a caprolactam oil layer separator, a lower-layer heavy organic phase outlet of the neutralized crystallization reactor is connected with an inlet of an ammonium sulfate centrifugal machine, an outlet at one end of the caprolactam oil layer separator is connected with a caprolactam collecting tank, an outlet at the other end of the caprolactam oil layer separator is connected with an ammonium sulfate mother liquor collection tank, an outlet at the lower end of the ammonium sulfate centrifugal machine is connected with an ammonium sulfate washing dryer, an outlet at the upper end of the ammonium sulfate centrifugal machine is connected with the ammonium sulfate mother liquor collection tank which is connected with the neutralized crystallization reactor through a mother liquor circulating pump. The neutralized crystallization system and method have the advantages that the heating and cooling capacities are integrated in reaction process, the energy consumption is low, the process is simple, and the purity of the product is high.

Description

technical field [0001] The invention relates to a preparation method of caprolactam, in particular to a neutralization crystallization system and method for preparing caprolactam from caprolactam rearrangement liquid. Background technique [0002] Caprolactam is one of the important raw materials for synthetic fibers and synthetic materials. It is mainly used in the manufacture of polyamide 6 fibers (nylon 6), resins and films. Chemically synthesized lysine has a wide range of uses in many fields such as textiles, plastics, and fine chemicals. The Beckmann rearrangement reaction of cyclohexanone oxime is the most important process in the production process of caprolactam, which plays a key role in product quality. [0003] At present, the industrial production of caprolactam rearrangement liquid (caprolactam sulfate) is obtained by rearranging cyclohexanone oxime under the action of oleum with concentrated sulfuric acid or oleum as a catalyst, and then the caprolactam rearr...

AI Technical Summary

Problems solved by technology

After the ammonia neutralization reaction is completed, to obtain caprolactam and ammonium sulfate products, it is necessary to evaporate the water added and reacted in the system. Since the neutralization process and the water evaporation process are carried out separately, the heat released during the neutralization reaction The loss needs to be taken away by cooling means, and the subsequent process of evaporating water needs to be heated, which consumes energy

Such a separate process results in the exothermic loss of the neutralization reaction and the heating energy consumption of the subsequent steaming process. This process consumes a lot of cooling and heat, high energy consumption, and unreasonable energy utilization.

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