Pitting on 5%Cr tubes

[SukhpalSingh]

what is the reason behind the occurrence of pitting corrosion on the outside surface of tubes (material 5% Cr) for heat exchanger that connected to bottom of naphtha stabilizer column in crude distillation unite?

 

[NBrink]

Total shot in the dark without looking at the process would be that you're getting poor separation in the crude overhead drum and are carrying water and chlorides into the stabilizer column, which is boiling dry in exchanger.

Would take a sample of the feed and see if it's cloudy (emulsified water), or if a separate phase will settle out...

Nathan Brink

 

[weldstan]

What fluids are on the shell side of the exchanger?