The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 03, 1985
Filed:
Apr. 21, 1983
Unie van Kunstmestfabrieken B.V., Utrecht, NL;
Abstract
An improved process for the preparation of urea from carbon dioxide and excess ammonia at elevated temperature and pressure. The urea solution from the urea synthesis zone is heated and stripped at an elevated pressure to decompose a portion of the ammonium carbamate contained therein and the ammonium and carbon dioxide containing off-gas produced is condensed in a first condensation zone. The stripped urea solution is heated at a reduced pressure in a decomposition zone to decompose a further portion of ammonium carbamate, and the ammonia and carbon dioxide containing off-gas thereby produced is condensed in a second condensation zone to form an aqueous ammonium carbamate solution. A portion of this aqueous carbamate solution is introduced into a desorption zone so as to produce an off-gas more concentrated with respect to ammonia and carbon dioxide than the ammonium carbamate solution, and the off-gas from this desorption zone is condensed into a further portion of such aqueous ammonium carbamate solution in a third condensation zone, maintained at a pressure between the pressure in the decomposition zone and about 40 bar, to form a more concentrated ammonium carbamate solution which is recycled to the urea synthesis zone.