为保障重沸器烟火管在天然气脱水装置中的关键作用,针对典型失效案例开展系统性分析以揭示失效机理,降低运行过程中的失效影响。通过宏观形貌检测、微观形貌检测、腐蚀产物分析、材料化学成分分析、力学性能测试及仿真模拟等方法进行失效分析研究。研究发现,重沸器烟火管直角弯头处为高温区域,高盐类矿化物返排液在外壁形成盐垢,同时内壁积垢与外部沉积共同导致传热效率下降和管体温度升高,引发塑性变形;烟火管直角弯头在腐蚀、塑性形变与应力的耦合作用下萌生裂纹,裂纹尖端的应力集中效应进一步加剧腐蚀,促使裂纹扩展,最终导致管体在焊缝热影响区附近开裂。研究成果为同类装置的设计改进与安全运行提供了参考。

To ensure the critical role of reboiler fire tubes in natural gas dehydration units, a systematic analysis of typical failure cases is conducted to reveal failure mechanisms and reduce the impact of failures during operation. The failure analysis is conducted through macroscopic morphology inspection, microscopic morphology inspection, corrosion product analysis, material chemical composition analysis, mechanical property testing, and simulation modeling. The study finds that the right-angle bend of the reboiler fire tube is a high-temperature region where high-salt mineral flowback liquids form scale on the outer wall. Internal wall scaling combined with external deposits leads to decreased heat transfer efficiency and increased tube temperature, causing plastic deformation. Cracks initiate at the right-angle bend of the fire tube due to the coupled effects of corrosion, plastic deformation, and stress. Stress concentration at crack tips further exacerbates corrosion, promoting crack propagation and ultimately resulting in cracking near the weld heat-affected zone. The results provide a reference for the design improvement and safe operation of similar devices.