,,,,良超

(北京化工大学，北京 100029)

失效分析

硫磺回收装置循环水换热器的腐蚀原因分析

陈轩,刘文彬,李俊林,杨剑锋,陈良超

(北京化工大学，北京100029)

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。

换热器；循环水；点蚀；微生物腐蚀

Abstract： 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.

Keywords： heat exchanger; circulating water; pitting corrosion; microbial corrosion

换热器是一种用于不同温度流体间热量传递的节能设备。换热器工作时，热量由温度较高的流体传递给温度较低的流体，根据需要即可作为加热器，也可用作散热源，满足不同工艺条件的需要。在现代大型化工厂中，换热器数量可以达到上百台，一旦发生事故，后果极其严重。一般采用循环水作为换热器冷却介质。循环水水质不仅会影响换热器的换热效率，还会影响装置安全。如果循环水水质不达标会导致换热器的加速腐蚀，降低换热效率。因此，在实际生产中厂方应加强循环水的水质监测和净化处理过程[1]。本工作以一台发生过严重腐蚀的硫磺装置的循环水换热器作为研究对象，结合现场实际情况与数据，力图从源头上找出换热器失效的根本原因，以及探讨该换热器腐蚀的基本机理,并提出切实可行的防腐蚀措施。……