[updated:LAST EDITED ON Nov-21-05 AT 05:45 AM (CDT)]When sulfidation occurs, will it generally attack the upper half of the process pipe on the straight run where you have lamellar flow?? My feeling is yes! The process streams generally don't fill the process line 100%. When the H2S vapor is formed by the decomosition of sulfur the vapor will rise to cause a vapor space and start attacking the metal. Please let me know if I'm wrong. I have seen this a couple of times; HGO piping coming from the crude column in the crude unit and at the stripper reboiler outlet piping in the diesel hydrotreater. Thanks

>Almost your true but do not confuse between the metal >dusting and SDFN. i F YOU NEED MORE FEEL FREE TO ASK. Thank you for your reply. Are you saying that what I may be see is metal dusting rather then sulfidation. Please explain in detail. Thanks Scott

Scott I am very sorry to miss understand you. I was to hurry and try to give you quick answer. The critical sulfide corrosion issue when the line is not filling 100 %. You know that sulfide sometime is volatile and condensed at the top of the line or crude Tank (investigate your tanks sure you will find corrosion at the roof you should apply coating on it). This vapor that condensed at the top of the line is contains electrolyte. The real name of this phenomenon is vapor space corrosion. If the temp. Is too high this will not happen. Refinery corrosion engineer