Process for urea production and related plant
AssigneeUrea Casale S.A.
InventorsFederico Zardi, Paolo Sticchi, Paolo Brunengo
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Abstract
A process for urea production from ammonia and carbon dioxide, in which part of the aqueous solution comprising urea, ammonium carbamate and ammonia obtained in a urea synthesis section is subjected to dissociation in a treatment section operating at a predetermined medium pressure for the recovery of the ammonium carbamate and of the ammonia contained in it, comprises the step of subjecting the urea aqueous solution resulting from the aforementioned dissociation step to decomposition in a low pressure urea recovery section.
Claims7
Process for urea production from ammonia and carbon dioxide, comprising the steps of:
- feeding ammonia and carbon dioxide into a urea synthesis section operating at a predetermined high pressure;
- making said ammonia and said carbon dioxide react in said synthesis section obtaining an aqueous solution comprising urea, ammonium carbamate and ammonia;
- feeding a part of said aqueous solution comprising urea, ammonium carbamate and ammonia to a treatment section operating at a predetermined medium pressure for the recovery of the ammonium carbamate and of the ammonia contained in it;
- subjecting said part of aqueous solution comprising urea, ammonium carbamate and ammonia to dissociation in said treatment section obtaining an urea aqueous solution and a vapour phase comprising ammonia, carbon dioxide and water;
- subjecting said vapour phase comprising ammonia, carbon dioxide and water to condensation in said treatment section obtaining an ammonium carbamate aqueous solution;
- recycling said ammonium carbamate aqueous solution to said urea synthesis section;
- characterized in that it comprises the further steps of:
- feeding said urea aqueous solution obtained by dissociation in said treatment section to a decomposer of a urea recovery section operating at a predetermined low pressure;
- subjecting said urea aqueous solution to decomposition in said decomposer of said urea recovery section obtaining a concentrated urea solution and a second vapour phase comprising ammonia, carbon dioxide and water;
- subjecting said second vapour phase to condensation in a condenser of said urea recovery section in fluid communication with said decomposer obtaining a recycle ammonium carbamate aqueous solution.
Dependencies are inferred from the claim text.