Abstract:

The frequent leakage of the tube bundle of dilution steam generator of ethylene plant in a petrochemical company has seriously affected the long-term and stable operation of the plant. The on-site macroscopic inspection results show that the leakage of the tube bundle is mainly concentrated in the gas-liquid phase change zone of the process water on the upper part of the shell side tube bundle, and its morphology has both corrosion grooves and “horseshoe” corrosion pits. Alkali corrosion and cavitation are the main reasons for the corrosion leakage of the dilution steam generator tube bundle, while the development of the tube bundle corrosion is promoted by such influencing factors as coking and medium design of the tube shell side. In view of the causes and influencing factors of corrosion leakage of tube bundle of dilution steam generator, the anti-corrosion control measures such as fine management of injection process, strict control of pH value of process water, introduction of toluene extraction process to control coking, and process water blowdown have been taken, and good protective effects have been achieved.

Key words: ethylene plant, dilution steam generator, corrosion leakage, corrosion products, corrosive medium, process anti-corrosion, cavitation, coking

摘要：

某石化公司乙烯装置稀释蒸汽发生器管束频繁发生泄漏，严重影响了装置的长周期平稳运行。现场宏观检查结果表明：管束的泄漏部位主要集中在壳程管束上部工艺水的气液相变区，其形貌兼具腐蚀沟槽与“马蹄形”腐蚀凹坑，碱腐蚀与气蚀是造成稀释蒸汽发生器管束发生腐蚀泄漏的主要原因，而结焦与管壳程介质设计等影响因素促进了管束腐蚀的发展。针对稀释蒸汽发生器管束腐蚀泄漏原因及影响因素，采取了精细化管理注剂工艺、严控工艺水pH值、引用甲苯萃取工艺控制结焦、工艺水排污等防腐蚀控制措施，取得了很好的防护效果。

关键词: 乙烯装置, 稀释蒸汽发生器, 腐蚀泄漏, 腐蚀产物, 腐蚀介质, 工艺防腐, 汽蚀, 结焦