Corrosion - steam/CTW same jacketed vessel

[jakegordonII]

We are operating a jacketed vessel (carbon steel construction) which operates both exo-thermic during a reaction phase and then the reactor is cooled between batches. The pitting is occurring on the vessel surface. Nitrogen is used to pad the air space during the draining and filling steps immediately before and after cooling stage. Comparison of similar operations at mulitple locations indicates the pitting problem is not common to all sites. Any comments on pitting in an application where same jacket is used for heating and cooling??

 

[jakegordonII]

I failed to mention that the steam heating is done initially at the beginning of a batch to elevate the temperature and start the reaction.