METHOD AND APPARATUS FOR PRODUCING UREA Russian patent published in 2023 - IPC C07C273/04 

FIELD: chemistry.

SUBSTANCE: invention relates to a method for producing urea. Method includes the following stages: a synthesis stage wherein urea is synthesised from ammonia and carbon dioxide to form a urea synthesis solution; a stage of high-pressure decomposition by heating the urea synthesis solution formed in the synthesis stage in order to decompose ammonium carbamate and release a gaseous mixture containing ammonia and carbon dioxide from the urea synthesis solution; and a condensation stage wherein at least part of the gaseous mixture produced at the stage of high-pressure decomposition stage absorbed and condensed in an absorbent medium and low-pressure steam is formed from steam condensate using the heat released during condensation. Said method for producing urea additionally includes the following stages: a) a stage of heat exchange of the steam condensate at a temperature above 90 °C with another fluid at a temperature of 90 °C or less among the media present in the method for producing urea, in order to cool said steam condensate to 90 °C or less; b) a stage of heating the steam condensate produced at said stage a) by heat exchange of the steam condensate produced at said stage a) with an additional fluid at a lower temperature than the temperature of the low-pressure steam among the media present in the method for producing urea; and c) a stage of supplying the steam condensate produced at said stage b) to the condensation stage in the form of steam condensate in order to generate low-pressure steam. Also proposed is an apparatus for implementing the method for producing urea.

EFFECT: proposed method and apparatus for producing urea allow performing heat recovery from a fluid at a relatively low temperature.

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