Failure Analysis of Spray-Type Coil Heat Exchanger in a Chlorosulfonic Acid Manufacturing Process

The chemical composition, microstructure and performance of the failed spray-type coil heat exchanger in a chlorosulfonic acid process were analyzed by optical emission spectrometer, optical microscope, scanning electron microscope, energy dispersive spectroscope and electrochemical testing. The results show that the chemical composition of pipe material of failed spray-type coil heat exchanger met the requirement of standard. Corrosion failure happened on the spray-type coil heat exchanger because of the formation of precipitated phase in manufacture process and the existence of residual stress in the elbow combined with the action of chlorosulfonic acid.