公开(公告)号：DE3162170D1

公开(公告)日：1984-03-15

申请号：DE3162170

申请日：1981-07-13

Applicant: BASF AG

Inventor： BORHO KLAUS DR ,  FROMM DIETER DR ,  SCHIER ERNST-JUERGEN DR ,  SCHNEEHAGE HANS HENNING DR ,  WIDMANN ALFRED DR

IPC: C07C273/10 ,  C07C67/00 ,  C07C239/00 ,  C07C273/12 ,  C07C273/16 ,  C07D251/62 ,  C07C126/08

Abstract: A process for isolating liquid urea and its thermal decomposition products from the off-gas of melamine synthesis, which gas has been freed from melamine by fractional condensation and then been washed with molten urea, wherein the off-gas, containing 2-10 kg of melt per kg of pure gas, is passed at 8-30 m/sec tangentially into the upper part of an axially symmetrical separation zone. As a result of the rotation imparted to the gas/liquid mixture, the two phases are separated from one another, and both pass downward through the separation zone. The gas and liquid are separately taken off at the bottom end of the separation zone. The residence time of the gas mixture in the separation zone is not less than 0.5 second.