Process for the synthesis of urea from carbon dioxide and ammonia
AssigneeSnam Progetti S.p.A.
InventorRenzo Gagliardi
Life of this patent
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Abstract
Urea is produced from ammonia synthesis effluent containing hydrogen, nitrogen, methane and argon, which is reacted with carbon dioxide to form ammonium carbamate. The hot ammonia synthesis effluent is contacted with the liquid effluents from the area synthesis reactor to dissociate the carbamate contained in said effluents into a gaseous effluent containing ammonia, carbon dioxide and oxygen, and to produce a further liquid reaction product containing urea. Oxygen is removed from the carbamate dissociation effluent, which is then fed to the ammonia synthesis step.
Claims3
In a method of making urea, which comprises synthesizing ammonia by reacting a gaseous mixture containing nitrogen and hydrogen to give a gaseous ammonia synthesis product which also contains hydrogen, nitrogen, methane and argon, reacting the ammonia synthesis product with carbon dioxide to form a liquid reaction product containing ammonium carbamate, and dissociating said ammonium carbamate to form urea;
- the improvement comprising contacting the hot ammonia synthesis effluent with the liquid effluent from the urea synthesis reactor in order to dissociate the ammonium carbamate contained in said effluents into a gaseous effluent containing ammonia, carbon dioxide and oxygen and to produce a further liquid product containing urea, removing oxygen from said carbamate dissociation effluent, and thereafter feeding the deoxygenated effluent to the ammonia synthesis step.
Dependencies are inferred from the claim text.