Abstract:

The 2^# continuous reforming unit of SINOPEC Yangzi Petrochemical Co., Ltd. adopts domestic ultra-low pressure continuous reforming technology. During the operation of the unit, there was a leak in the steam heat exchange pipe of the steam drum system in the convection section of the furnace, which forced the unit to be shut down for maintenance. A series of studies have been conducted on failed heat exchange pipes, including perforation analysis, material composition analysis, and energy spectrum analysis. Through perforation analysis, it is determined that corrosion perforation occurs on the inner wall and extends towards the outer wall. Through energy spectrum analysis and X-ray diffraction analysis, it is found that the main corrosion products of the scale sample on the inner wall of the heat exchange pipe are Fe₂O₃ and Fe₃O₄. Combined with the oxygen content data of the deoxygenated water, it is determined that there is oxygen corrosion phenomenon. After cleaning the scale sample, it is found that the sediment amount exceeds 600 g/m³, and the scale deposition amount exceeds the standard. Based on the above, the cause of the leakage is the corrosion perforation of the heat exchange pipe in the steam drum system, which extends from the inside to the outside of the pipe under the combined action of oxygen corrosion and underdeposit corrosion. In response to the reasons for the leakage, this article proposes preventive measures from aspects such as water quality monitoring, furnace shutdown protection, and regular spot checks.

Key words: continuous reforming, steam drum system, steam heat exchange pipe, leakage, scale sample analysis, oxygen corrosion, underdeposit corrosion

摘要：

中国石化扬子石油化工有限公司2号连续重整装置采用国产超低压顺流连续重整技术，在生产运行过程中，加热炉对流段汽包系统蒸汽换热管出现泄漏现象，装置被迫停工检修。对失效换热管开展了穿孔分析、材质化学成分分析、能谱分析等研究。通过穿孔分析判断：腐蚀穿孔在内壁产生并向外壁扩展。通过能谱分析和X射线衍射分析得知：换热管内壁垢样的腐蚀产物主要是Fe₂O₃和Fe₃O₄,结合除氧水的氧含量数据，判断换热管存在氧腐蚀。对垢样进行清洗得知：沉积物质量浓度超过600 g/m³,垢污沉积量超标。综合判断泄漏原因：汽包系统换热管在氧腐蚀与垢下腐蚀的综合作用下，发生了由管内向管外扩展的腐蚀穿孔。针对泄漏原因，从水质监控、停炉保护、定期抽检等方面提出了预防措施。

关键词: 连续重整, 汽包系统, 蒸汽换热管, 泄漏, 垢样分析, 氧腐蚀, 垢下腐蚀