裂解炉炉管的损伤机理及剩余寿命分析

通过研究BA-1102裂解炉炉管的各种试验数据,分析了该炉辐射段炉管失效的原因,并且利用Larson-Miller参数外推法估算了该炉管的剩余寿命。结果证明,BA-1102裂解炉炉管内部存在铸造缺陷,且运行16000 h后炉管材质劣化产生微裂纹是炉管失效的内因;炉管渗碳部分与非渗碳部分之间存在膨胀差,在紧急停炉时引起材料内部存在很大的拉应力,该应力与其他应力共同作用,使炉管在停炉过程中受到较大损害,致使在切割炉管时外力造成炉管脆断。BA-1102裂解炉炉管在管壁平均温度为1000℃时,剩余寿命不大于44794 h(约5年)。

Analysis in Mechanism of Damage and Remaining Life of Tube in Steam Cracker

Based on the test data of tube in steam cracker, the radiation tube failure is analyzed and the remaining life estimated with Larson-Miller parameter extrapolation. It is proved that the immanent cause for the failure is flaws from casting in the tubes, micro-fissure in the tubes resulted from the material degradation through 16 000 hours of operation; there is an expansion coefficient difference between the earburized and noncarburized area in the tube, a great internal tensile stress emerged in the tube when an emergency shutdown carried out, the stress interacted with others, severe damages of the tube appeared in the shutdown, brittle fracture of the tube caused by external force of cutting in overhaul. The remaining life of radiation tube is less than 44 794 hours （about 5 years） under average temperature of 1 000 ℃.