METHOD OF PRILLING UREA Russian patent published in 2025 - IPC C07C273/04 C07C273/14 B01J2/04 

FIELD: chemistry.

SUBSTANCE: disclosed is a method of prilling urea melt and a method of producing solid urea, which use calcium lignosulphonate or carboxymethyl starch as an additive for producing commercial urea which does not contain formaldehyde. In the prilling method, urea melt is distributed in the form of droplets in a prilling tower; then, these droplets are solidified when falling down in a countercurrent of an ascending air flow. Urea melt contains calcium lignosulphonate and/or carboxymethyl starch as a prilling additive. Urea melt is obtained in a urea synthesis unit, where urea is synthesized from ammonia and carbon dioxide at synthesis pressure to form a reaction effluent containing urea, water and unconverted ammonium carbamate. Reaction effluent is treated in one or more regeneration sections at lower pressure to regenerate unreacted reagents to obtain purified aqueous urea solution, which is treated in an evaporation section to remove water and obtain urea melt. Prilling additive is added to the purified aqueous solution before evaporation or added to the urea melt.

EFFECT: providing a process for prilling urea with a safe and acceptable additive which can improve mechanical properties of urea prills without formaldehyde.

14 cl, 1 dwg, 1 ex