Corrosion Failure Analysis and Countermeasures of Heat Exchanger of Alcohol-Ammonia Gasification Unit

A heat exchanger of an alcohol-ammonia gasification unit in a petrochemical plant suffered from corrosion and perforation failure in the process of circulating water cooling high-pressure sealing water. The failure causes of heat exchange pipes were analyzed through examinations of the chemical composition of the corroded material, circulating water quality and corrosion products. The results showed that the fluid velocity at the inlet of the heat exchanger shell side was too low due to improper design, resulting in a large number of corrosive ions of sulfur and chlorine precipitated on the pipes from the circulating water, eventually leading to the corrosion of the heat exchange pipes. Through the improvement of the shell side inlet structure, the fluid velocity at the corroded part was increased from 0.7 m/s to more than 1 m/s, so corrosive ions no longer stagnated on the heat exchange pipes, thereby improving the corrosion of the heat exchanger.