Process for urea production
AssigneeUrea Casale S.A.
InventorsGiorgio Pagani, Umberto Zardi
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Abstract
An improved process for urea production as well as a method of retrofitting a pre-existing urea plant based on the Stamicarbon process are disclosed. According to the invention, a high yield reaction space fed by highly pure reagents (NH3 and CO2) and a separating section of the solution leaving the high yield reaction space are added to the pre-existing urea plant, means being provided for recirculating ammonia and carbammate solutions obtained in the separating section to the added high yield reaction space and to the pre-existing reactor respectively.
Claims8
A continuous process of producing urea comprising the steps of:
- reacting ammonia and carbon dioxide in a first reaction space at high temperature and pressure, the ammonia/carbon dioxide ratio being less than 3;
- effecting a gas stripping with said carbon dioxide of a first reaction mixture leaving said first reaction space;
- feeding the stripped first reaction mixture to a first urea recovery section;
- feeding high purity ammonia and carbon dioxide to a second reaction space;
- feeding a second reaction mixture including urea, carbamate and unreacted ammonia leaving said second reaction space, to a second recovery section;
- separating urea, carbamate and unreacted ammonia in said second recovery section;
- recycling the carbamate and unreacted ammonia leaving said second recovery section respectively to said first and second reaction spaces.
Dependencies are inferred from the claim text.