Leakage Reason of Tubes within Heat Exchanger of Residue Fluid Catalytic Cracking Unit in an Oil Refinery

Leaking of tubes within heat exchanger of residue fluid catalytic cracking unit in an oil refinery occurred during running. The failure reasons were analyzed by means of optical microscopy, scanning electron microscopy and energy disperse spectroscopy. The results show that serious pitting occurred in the inner surface of the tube, and the corrosion products mainly consisted of Fe(OH)₃, FeS and FeCl₂, corrosive ions such as Cl^- and S^2- in the heat exchange tubes were the main reason for the corrosion and failure of tubes.