Patent ID: 11858882
Assignee: YARA INTERNATIONAL ASA
Field: Chemical engineering (Chemistry)
Classification: CPC C  B | IPC B  C

Claim 0:
1. A method for providing a target aqueous urea composition with a target concentration urea, comprising the steps of:
a) reacting CO2 and NH3 in a synthesis section to form a crude urea mixture;
b) separating the crude urea mixture into a first aqueous urea solution and a process condensate using a separating section;
c) passing the process condensate through a first desorption column to provide a first partially purified flow;
d) passing at least part of the first partially purified flow through a hydrolyser to provide a second partially purified flow;
e) passing the second partially purified flow through a second desorption column to provide a purified water flow;
f) optionally concentrating the first aqueous urea solution in a pre-evaporator to provide a concentrated second aqueous urea solution; and
g) mixing the first aqueous urea solution and/or the second concentrated aqueous urea solution with at least part of the first partially purified flow and at least part of the purified water flow in such a ratio to provide a target aqueous urea composition with the target concentration urea.