Failure analysis on synergistic effect of erosion and corrosion on failed fittings in specialty chemical plant. Part II: Control valve

摘要

Failure analysis was carried out on a control valve in the steam system of a specialty chemical plant. Comprehensive analyses were conducted to investigate the operating conditions, base materials, macroscopic, and microscopic morphologies of the failed steam control valve and a computational fluid dynamic model was also adopted. The results showed that the synergistic effect of electrochemical corrosion favored by chlorides and two phase flow erosion accounted for the premature failure of the steam control valve. Considering the fact that the valve was designed by a German company, assembled by an American company and used in a Chinese company, our failure analysis seems to be crucial for the imputation of the responsibility. The failure mechanisms were discussed and the relevant countermeasures were proposed to prevent the occurrence of similar failure again.