重催装置换热器管束失效分析

重催装置由于特殊的服役环境,多发生介质腐蚀,导致装置泄漏,严重的甚至断裂。针对换热管服役3a后发生腐蚀失效的问题,对其进行宏观检验、化学成分、XRD以及金相组织分析的同时,采用扫描电镜分析换热管微观形貌,用能谱仪对腐蚀产物进行成分分析。结果发现,换热管内表面发生了严重的点蚀,腐蚀产物主要是磁铁矿,腐蚀产物中含有Cl^-和S^2-,这是导致管束失效的主要原因。

Failure Analysis of Heat-Exchanger Tube of Residue Fluid Catalytic Cracking Unit

Serious corrosion occurrs and causes the device to leak, or even rupture in petrochemical equipment because of its unique operation environment. Aiming at the failure on a heat-exchanger tube after three years of service, macro examination, chemical composition, XRD and microstructure were examined respectively. Moreover, the fracture morphology and corrosion products were analyzed by SEM and EDS. Results showed that serious pitting occurred in the inner surface of the tube, and the corrosion products mainly consisted magnetite. Corrosive ions such as Cl^-and S^2-in the heat-exchanger tubes were the main reasons for the corrosion and failure of tubes.