METHOD FOR COMBINED PRODUCTION OF UREA AND UREA-AMMONIUM NITRATE Russian patent published in 2020 - IPC C07C273/04 C07C273/10 C07C273/16 C07C275/02 C01C1/18 C05C1/00 C05C9/00 B01D3/00 

FIELD: chemical or physical processes.

SUBSTANCE: invention relates to a method of combined production of urea and urea-ammonium nitrate. Method comprises a) preparing an aqueous solution of urea, using in the synthesis of urea as raw materials ammonia and carbon dioxide, b) obtaining ammonium nitrate from ammonia and nitric acid at the step of producing ammonium nitrate, c) wherein at least a portion of the aqueous urea solution is mixed with at least a portion of the ammonium nitrate to obtain urea-ammonium nitrate at the step for producing urea-ammonium nitrate, and d) synthesis of urea involves reacting ammonia and carbon dioxide at synthesis pressure to form a reaction mixture of urea, comprising urea and unreacted materials, and also includes regeneration of unreacted materials at several stages of regeneration, including at least a first regeneration step operating at a first regeneration pressure which is less than the synthesis pressure, and a second regeneration step operating at a second regeneration pressure, which is less than first regeneration pressure. At that, in the method: e) exhaust gases released at carbamate decomposition step at the second regeneration stage and containing unreacted ammonia, at least partially condensed at second regeneration pressure to produce exhaust gas condensate, e) at least a portion of the exhaust gas condensate or solution containing at least a portion of the exhaust gas condensate is recycled to a first regeneration step and g) discharging ammonia-containing stream from first regeneration step at first regeneration pressure and feeding to ammonium nitrate production step. Also disclosed are apparatus for combined production of urea and urea-ammonium nitrate and a method of modifying the apparatus.

EFFECT: invention enables to more efficiently combine the steps of producing urea and the step of producing ammonium nitrate in producing a final product of urea-ammonium nitrate, as well as increase safety and reduce emissions, in particular reduce ammonia emission risks.

17 cl, 7 dwg