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.

Date of Patent:
Jul. 30, 2002

Filed:

Oct. 30, 2001
Applicant:
Inventors:

Kinichi Yoshida, Chiba, JP;

Kenji Yoshimoto, Chiba, JP;

Yasuhiko Kojima, Chiba, JP;

Assignee:

Other;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C07C / ;
U.S. Cl.
CPC ...
C07C / ;
Abstract

A urea synthesis process with improved heat economy, wherein a urea synthesis solution obtained by removing most of the unreacted ammonium carbamate by stripping with carbon dioxide at a pressure approximately equal to a urea synthesis pressure is subjected to a high and low pressure decomposition. The gas mixture obtained from the high-pressure decomposition is condensed in at least two steps. Gases obtained from the stripping of the urea synthesis solution, after an initial condensation may be alternatively routed into the high-pressure decomposition column thus facilitating the decomposition of unreacted ammonium carbamate; may be mixed with off-gases from the high-pressure decomposition column and routed to an indirect heat-exchanger for concentrating the aqueous urea solution and facilitating the condensation of the off-gases from the high pressure decomposition column; or may be routed to a condenser for the gas mixture obtained from the high-pressure decomposition after it has underwent indirect heat-exchange with the aqueous urea solution, thus facilitate the further condensation of these gases.


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