This document summarizes the manufacturing process of urea. Urea is made through two reactions: first ammonium carbonate is formed from carbon dioxide and ammonia under high pressure and heat. Then, the ammonium carbonate decomposes to form urea and water. The reactions take place in an exchanger-reactor at high pressure and temperature. The urea product is purified, cooled, and dried before bagging and shipping.

1. UREA
Prepared by- Mr. Vishal B. Thakare
(M.Tech, Chemical, SVNIT, Surat)
Assistant Professor, PARUL UNIVERSITY
Vadodara
vishalbt88@gmail.com

2. UREA
 Urea (NH2CONH2) or carbamide is an organic compound has two —NH2
groups joined by a carbonyl (C=O) functional group.
 Urea has the highest nitrogen content available in a solid fertilizer (46%).
Raw Material
CO2, NH3
Reaction
CO2 + 2NH3 NH2COONH4 ΔH = - 37,021 Kcal
(Ammonium Carbamate)
NH2COONH4 NH2CONH2 + H2O ΔH = + 6.3 kcals
(Urea)
Side Reaction-
2NH2CONH2 NH2. CO. NH. CO. NH2 + NH3
(Biuret)

4. Urea is always made in an ammonia plant because it produces CO2
as by product, which can be used directly without further treatment.
Two reactions are involved in the manufacture of urea. First
ammonium carbonate is formed under pressure by highly exothermic
reaction between carbon dioxide and ammonia followed by the
endothermic decomposition reaction
Liquid ammonia, gaseous carbon dioxide and recycle materials
charged in the heat exchanger-reactor at the pressure of 14MPs at
170 – 190oC to form carbamate
The carbamate decomposition reaction is both slow and
endothermic. The mixture of unreacted reactants and carbamate
flows to the decomposer.

5. The stoichiometric ratio of CO2/NH3 conversion to urea is essentially about
55%, but by using an excess of CO2 (or NH3) the equilibrium can be driven
as high as 85%.
Molten mass of ammonium carbonate from synthesis reactor passed into
distillation column where unconverted carbon dioxide and ammonia, along
with un decomposed carbamate, must be recovered and reused.
Purified molten mass of ammonium carbonate passed into evaporator
section to decompose into urea.
Molten urea get cooled and dried with the aid of chilled air in prilling
tower.
 Dried urea is sent to bagging and shipping operation.