乙烷裂解炉管开裂原因分析

通过对材质为35Cr45Ni+NbMA的乙烷裂解炉炉管进行宏观形貌、微观形貌、扫描电镜、金相、化学成分等方面的分析,分析了炉管失效的原因,提出了相应的预防措施和建议。结果发现:炉管长期高温服役,力学性能下降,炉管内形成的厚结焦层与炉管母材的热膨胀系数之间的差别,导致在停炉过程中产生超过常温断裂强度的高水平应力,是该乙烷裂解炉炉管断裂失效的主要原因。

Analysis of Furnace Tube Cracking for Ethane Pyrolysis

The failure causes of the ethane cracking furnace tube were analyzed,through analyzing ethane cracking furnace with material of 35Cr45Ni＋NbMA based on theoretical calculation and a series of tests including macro and micro morphological observations,SEM,metallographic examination,chemical composition examination and mechanical performance test.The corresponding protective measures were also put forward.It showed that long-term high operation temperature,the different thermal expansion coefficients between the internal tube coking bodies and the furnace tubes which lead to the hoop stress exceeded the furnace tube strength in the shutdown process and ambient conditions were the main causes of the failure.