再生器内取热盘管失效原因分析

FAILURE ANALYSIS OF CATALYST COOLER IN REGENERATOR

应用光学显微镜和扫描电子显微镜研究分析了催化裂化装置再生器内Ｕ型取热盘管失效的原因。该管具有应力腐蚀开裂的特征，管材在受到介质腐蚀时，发生晶界损伤，进而在工作应力作用下，在这些薄弱部位产生裂纹。裂纹从管内壁开始向外扩展，裂纹面上有负二价硫离子存在。建议新装置运行中注意水处理和设备防护。

The causes of failure of the U-type catalyst cooler in regenerator of FCCU were analyzed with optical microscope and scanning electron microscope. This U-tube is characterized by stress corrosion cracking. When the tube corroded in the medium, intergranular corrosion occurred. Under the action of working stress, further cracking took place in these weak positions. Cracks expanded from the inner tube wall to external wall, and divalent sulfur ions were found on the surface of cracks. It is suggested that in operation of the unit attentions should be paid to water treatment and equipment corrosion prevention.