Failure Analysis of Corroded Tube–Tubesheet in an Oxy-chlorination Reactor

摘要

After the replacement of a 20-year-old oxy-chlorination reactor, the top tube–tubesheet of the newly installed reactor was seriously corroded and lasted for only 40 days. Samples extracted from the retired and new tube–tubesheet were examined to identify the possible causes for the failures. Due to the corrosion, the sealing design (tube expansion followed by seam weld) in the tube–tubesheet was not a successful methodology to prevent leakage in this chemical process. However, this short-term breakdown is attributed to the operating conditions (operating pressure and service temperature) in this petrochemical refinery, because no major discrepancy existed in the material characterization of the new and retired top tube–tubesheet.