某石化厂硫磺回收装置的循环水换热器发生了严重腐蚀，通过分析现场腐蚀状况、腐蚀产物及循环水水质报告等对换热器腐蚀原因进行分析。结果表明：该换热器的腐蚀以点蚀为主，微生物腐蚀为辅。由于循环水中存在大量杂质离子，导致换热器内部环境变为弱碱性，引起点蚀；另外，换热器循环水中存在的少量异养菌是导致微生物腐蚀的主要原因。

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.