A kind of ammonium sulfate crystallization method and device thereof

Abstract

The invention discloses an ammonium sulfate crystallization method and a device thereof, which belong to the field of chemical industry. The device uses two crystallizers in series and adopts a two-effect vacuum crystallization process, the first effect is neutralization crystallization, and the second effect is evaporation crystallization. The first effect is to neutralize the slurry produced by the crystallization with a large proportion of fine crystal particles, and the second effect is an evaporation crystallization system to obtain ammonium sulfate with a large proportion of large-grained ammonium sulfate. The device makes full use of the heat of gas ammonia dissolution and the neutralization heat of the neutralization reaction between sulfuric acid and ammonia, and uses the secondary steam of the neutralization crystallizer as a heat source to reduce the consumption of circulating water, increase the proportion of large-grained ammonium sulfate, and reduce the production of caprolactam at the same time. Package loss.

Description

Technical field: [0001] The present invention relates to the field of chemical plant, in particular to a method and apparatus is applied to crystallization of ammonium sulfate caprolactam means. Background technique [0002] Caprolactam is an important organic chemical raw materials, engineering plastics mainly for the production of nylon 6 and nylon 6 fiber. Nylon 6 plastic primarily as automotive, marine, electronic appliances, consumer goods and industrial machinery components and components, can be made of nylon 6 fiber textile, carpet and industrial yarn such as silk, in addition, also for the production of anti-caprolactam antiplatelet agents, and other production laurocapram wide range of uses. The main production methods caprolactam are: [0003] 1, cyclohexanone - hydroxylamine [0004] This method is based on cyclohexanone as the main feedstock caprolactam production. Wherein the hydroxylamine production process there are three routes, namely Method HSO, HPO method, NO ...

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Problems solved by technology

[0024] a) In the single DTB type ammonium sulfate neutralization crystallizer widely used at present, most of the ammonium sulfate solid particles are 0.6~1.2mm, and the ammonium sulfate solid particle size is more than 2mm. The proportion of ammonium sulfate crystals is less than 10%, usually at about About 5%, the proportion of ammonium sulfate crystals above 2mm is small, and the solid particle size is small. However, because the price of large-grained ammonium sulfate crystals is about 30-45 US dollars / t ammonium sulfate higher than that of small-grained ammonium sulfate crystals, that is, about 200-300 yuan RMB / t ammonium sulfate, ammonium sulfate caprolactam plant has a large output of ammonium sulfate, about 1.5t ammonium sulfate / t caprolactam, this process technology with small proportion of large ammonium sulfate particles results in poor economic efficiency of ammonium sulfate crystallization plant

[0025] b) At present, the content of caprolactam in ammonium sulfate solids is usually around 0.1%wt, resulting in the loss of caprolactam, and there is still room for reducing the loss of caprolactam in technology;

[0026] c) A single DTB type ammonium sulfate neutralizes the secondary steam generated at the top of the crystallization tower, which is generally cooled by circulating cooling water. The energy has not been rationally utilized, and the cooling water consumption is relatively large

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