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:
Jan. 03, 1978
Filed:
Aug. 29, 1972
Dirk J Venderbos, Geleen, NL;
Stamicarbon, N.V., Geleen, NL;
Abstract
A process for preparing urea by the intermediate formation of ammonium carbamate is disclosed, wherein the process involves reduced use of high pressure steam, and the reduced production, as a by-product, of low pressure steam, compared to prior art processes. Ammonium carbamate is formed from ammonia and carbon dioxide in a first reaction zone at a pressure of 90 - 140 atmospheres. Thereafter, the ammonium carbamate is partly converted into urea in a second reaction zone at about the same pressure as the first reaction zone until at least 40% of the equilibrium amount of the urea has formed, and then ammonium carbamate present in the solution from the second reaction zone is converted into additional urea in the third reaction zone at a pressure of at least 160 atmospheres until at least 85% of the equilibrium amount of urea has been formed. The resulting urea synthesis solution is partially expanded and subjected to a stripping treatment, with the gases released in the stripping treatment recycled to the first reaction zone.