Patent ID: 8106241
Filing Date: 2012-01-31
Classification: B01J,C07C,Y02P

Abstract:
1. An enhanced process for the synthesis of urea from ammonia and carbon dioxide, at a high pressure and temperature, with the formation of ammonium carbamate as an intermediate, which includes a high-pressure synthesis section, comprising at least one separation of the unconverted ammonium carbamate by decomposition-stripping with ammonia, carried out in vertical equipment, commonly called a stripper, wherein said separation also comprises a feeding of a CO 2 stream in the lower part of said stripper, said stream being, heated to a temperature ranging from 130 to 230° C. in a quantity of 1 to 15% by weight with respect to the total weight of the fresh CO 2 fed to the process, and containing a passivating agent in such a quantity that its equivalent content of O 2 in moles varies from 0.05% to 0.80% with respect to the moles of CO 2 of said stream.