催化裂化装置旋风分离器翼阀断裂原因分析

通过化学成分、显微组织、力学性能、断口和能谱分析,对某催化裂化装置S30409翼阀导流锥断裂事故进行原因分析。结果表明:翼阀长期高温运行,基体组织和焊缝中形成了大量σ相;σ相的析出导致材料塑性和韧性下降;装置切换风机运行时,工况波动导致旋风分离系统产生振动,冲击翼阀,使得承受较大应力集中的导流锥焊缝处累积损伤,形成微裂纹;振动循环加速裂纹扩展,最终导致翼阀导流锥断裂脱落。

FRACTURE ANALYSIS OF CYCLONE SEPARATOR WING VALVE IN FCC UNIT

Based on the analysis of chemical composi-tion,microstructure,mechanical properties,fracture and energy spectrum,this paper analyzes the fracture causes of S30409 wing valve diversion cone in an FCC unit.The results showed that a large amount ofσphase was formed in the matrix structure and weld during the long-term high temperature operation of the wing valve;precipitation ofσphase led to decrease of the plasticity and toughness of the material;when the device was switchedto the fan operation,the fluctuation of the working condition resulted in the vibration of the cyclone system,which impacted the wing valve;the accumulated damage at the weld seam of the guide cone with large stress concentration formed micro-cracks;the vibration cycle accelerated the crack expansion and finally led to the fracture and fall-off of the guide cone of the wing valve.