Corrosion Reason Analysis of Circulating Water Heat Exchanger in a Sulfur Recovery Unit

The heat exchanger of circulating water in a sulfur recovery unit of a petrochemical plant was seriously corroded. The corrosion causes of the heat exchanger were analyzed through analyses of field corrosion conditions, corrosion products and water quality report of circulating water. The results show that pitting corrosion was main corrosion of the heat exchanger, and microbial corrosion was auxiliary. There were a lot of impurity ions in the circulating water, which changed the internal environment of the heat exchanger into slight alkalinity, and caused pitting. A few of heterotrophic bacterium existing in the circulating water was the main reason of microbial corrosion.