油浆蒸发器腐蚀泄漏分析

Corrosion Leakage Analysis of Slurry Evaporator

对催化裂化装置油浆蒸发器管束的腐蚀形貌进行了宏观检查,其具有典型的空泡腐蚀特征。采用光谱分析、扫描电镜分析、能谱分析及X射线衍射分析等方法分别对管束的化学成分、微观腐蚀形貌及腐蚀产物进行了分析,结果表明,换热器管束化学成分符合标准要求,管束腐蚀部位有大量的Fe元素和O元素,且腐蚀产物的主要物相为Fe_2O_3。从溶解氧、催化剂、换热管结构及空泡腐蚀等影响因素对管束的腐蚀泄漏原因进行了分析,认为换热器管束表面的腐蚀为空泡腐蚀,而导致空泡腐蚀的主要原因是换热管表面凹凸不平的螺纹结构,为避免管束表面发生空泡腐蚀,建议将螺纹管更换为光管。此外,壳程无盐水中溶解氧的电化学腐蚀对空泡腐蚀的发展起到了积极的促进作用,在两者的重复交替循环作用下管束发生了腐蚀穿孔泄漏。

The macro corrosion morphology was examined for tube bundle of slurry evaporator in fluid cat- alytic cracking unit, which had typical cavitation corrosion characteristic. And the chemical component, micro corrosion morphology and corrosion products of the tube bundle were analyzed adopting spectral a- nalysis, SEM, EDS and XRD. The research result indicated that the chemical component of tube bundle of slurry evaporator meeted a criterion, and large amounts of Fe and O element were detected in the corrosion products of tube bundle. Moreover ,Fe203 - rtH2O was main compound of corrosion products by analyzing. Analyzed the corrosion leakage reason of tube bundle from some influence factors, such as the dissolved oxygen, catalyst, technological process, and cavitation corrosion, and the corrosion type of tube bundle of slurry evaporator was cavitation corrosion. The screw structure was the main reason which leaded to cavita- tion corrosion leakage, in order to avoiding cavitation corrosion screw pipe should be exchanged to smooth pipe. Furthermore, of tube bundle of slurry evaporator. And , the electrochemical corrosion of dissolved oxygen promoted cavitation corrosion actively in the process of corrosion leakage of tube bundle, and the corrosion leakage of tube bundle occurred for both of repeating and circulating.