H2O2 solution influence on carbon steel equipment

[Guest Zauberberg]

We are using 35% H2O2 for oxidizing spent caustic (strength between 1-10%, rich in sodium sulfide and sodium mercaptides, ranging between 200-20000ppmw). My concern is about using carbon steel vessel for mixing streams of caustic and H2O2 solutions, with recirculation pump ensuring 100% oxidation. How does the presence of H2O2 affect carbon steel equipment? Dillution rate of caustic is very big (max. allowable concentrations of sulfides and mercaptides before injecting H2O2 are 4500ppmw; vessel volume is 25m3), so unreacted H2O2 would be in very small concentrations. Oxidation is controled by H2O2 dozing and reaction temperature (<80C).

 

If you have any suggestions, please help. Sorry for my English; it's not so good, I suppose.

Thank you in advance. Wish you good health,

 

Zauberberg