PROCESS AND APPARATUS FOR THE REMOVAL OF AMMONIUM CARBAMATE FROM A UREA-SYNTHESIS SOLUTION

摘要

A process and apparatus for the removal of ammonium carbamate from an aqueous urea solution wherein the aqueous urea solution is introduced into a stripping zone and caused to flow down a heat exchange wall as a thin film while being heated and contacted in counter-current relation with a gaseous stripping agent. The aqueous urea solution, while being stripped, is heated for at most 5 seconds at a temperature in the range of from 180 - 195 DEG C and thereafter cooled to a temperature of from 155 - 170 DEG C.