PROCESS FOR THE PREPARATION OF UREA

摘要

Process for the preparation of urea from ammonia and carbon dioxide in which a urea synthesis solution containing urea, ammonium carbamate and unconverted ammonia is formed in a synthesis zone, a part of the urea synthesis solution being transferred from the synthesis zone to a medium-pressure treatment zone operating at a pressure of 1-4 Mpa, and a gas stream from the medium-pressure treatment zone being absorbed into the low-pressure ammonium carbamate solution from the urea recovery section.