PRODUCTION OF AMMONIUM SULPHATE ON INDUSTRIAL SCALE Russian patent published in 2024 - IPC C01C1/242 C07D201/04 B01D11/04 B01D9/02 C07D201/16 B01D17/02 

FIELD: chemistry.

SUBSTANCE: present invention relates to a method and apparatus for producing crystalline ammonium sulphate (AS). Method on a plant comprising a section for carrying out the Beckmann rearrangement reaction, a neutralization section, a first liquid–liquid separation section (l–l), first and second extraction sections, the first solvent extraction section, the first and second evaporation crystallisation sections and the first liquid–solid (l–s) separation section include several stages. At step a) sulfuric acid and/or oleum and cyclohexanone oxime are loaded into the section for carrying out the Beckmann rearrangement reaction and reacting them. At step b), a mixture containing ε-caprolactam formed at step a) is discharged into a neutralization section. Then, at neutralization step c), ammonia and water are added to the mixture containing ε-caprolactam to obtain a first aqueous phase of AS and an aqueous phase of ε-caprolactam. At step d) the first aqueous phase of AS and the aqueous phase of ε-caprolactam, obtained in the neutralization section of the first l–l separation section, are separated and treating at step e) a first aqueous phase AS obtained at step d). For this purpose, the first AS phase is subjected to extraction with the first organic solvent in the first extraction section, as a result of which a phase containing a first organic solvent and ε-caprolactam is obtained, and a first aqueous phase of AS subjected to extraction treatment. Treated first AS phase is loaded into the first solvent extraction section, wherein the first organic solvent is extracted and the separated first aqueous AS phase is obtained. Further, the separated first aqueous phase of the AS is loaded into the first evaporation crystallisation section and performing evaporation crystallisation therein to obtain crystalline AS and mother solution in a first evaporation crystallisation section, note here that mother solution represents an aqueous phase of AS enriched with organic components as compared to separated first phase of AS fed into first evaporation crystallisation section. Mother solution and the suspension containing crystalline AS are discharged from the first evaporation crystallization section and loading it into the first separation section of the l–s is for separation of crystalline AS. Step f) treats the aqueous phase of ε-caprolactam obtained in step d) by subjecting it to extraction treatment in a second extraction section with a second organic solvent, wherein a phase is obtained containing a second organic solvent and ε-caprolactam, and a second aqueous phase of AS containing organic components. Method is characterized by that the mother solution, which is discharged from the first evaporation crystallisation section, and/or the second aqueous phase of the AS containing organic components, is loaded into the second evaporation crystallisation section so that a three-phase system is formed, including a liquid oil phase containing organic components, a crystalline phase of AS and a liquid aqueous phase containing AS. At that, at least a liquid oil phase is separated from the three-phase system.

EFFECT: providing an economical and environmentally friendly method of producing high-grade ammonium sulphate.

13 cl, 6 dwg, 1 ex