Hi,

Our stripper bottom outlet line CS flanges having carbamate/urea at 2350 psig and 380 deg F is leaking. One slip-on flange is of line and other is of Control valve. Leakage is varying from 30 dpm to 250 dpm. More tightening of flanges not possible without damaging titanium gasket. Box-up is not an option as leaking urea will corrode the CS flanges. By applying air, leakage stopped due to carbamate/urea solidification. but as soon as we removed air, leakage started again.

Plant shutdown is not an option for now. What will be more preferable i.e will less corrode the flanges:
a) leaking carbamate/urea solution
b) Solidified carbamate/urea solution
&
What will be the extent of crevice corrosion in flanges due to solidified stagnant carbamate/urea?