Question

Describe the manufacturing of Urea with a neat flow sheet.

Answer 1

Urea is manufactured by reacting ammonia and carbon dioxide in an autoclave to form ammonium carbamate. The operating temperature is 135^oC and 35 atm pressure, the chemical reaction is an endothermic reaction and so ammonia is maintained in excess to shift the equilibrium towards urea formation. Urea production is based on two main reactions.

1. Formation of ammonium carbamate

2. Dehydration of  ammonium carbamate to produce molten urea