催化裂化装置待生滑阀阀杆脱扣原因分析与处理

Cause analysis and treatment of the valve stem detachment of the spent catalyst slide valve in FCCU

介绍了某催化裂化装置沉降器料位由41%开始突升并在调整过程中产生波动的原因及解决措施。分析原因:待生滑阀控制失灵造成沉降器料位波动。通过现场拆除待生滑阀阀杆和控制机构连接块、旋转和抽拉阀杆等调整措施,确认阀板和阀杆脱扣。根据对阀杆连接结构的分析,采取调整旋转和抽拉阀杆等措施恢复了装置生产,并在阀杆180°方向带压开孔安装了一套临时的顶杆与原阀杆共同控制待生滑阀,保证了装置长周期运行。为明确故障原因,采用了流场模拟的方法对滑阀内压力云分布、流体速度分布、催化剂颗粒分布及吹扫蒸汽的控制进行了相关计算,得出吹扫蒸汽的流量控制对阀杆连接处的冲蚀具有较大影响。该结论在检修中得到了较好的验证。

The reasons and solutions for the sudden rise of the material level in the settler of a FCCU from 41%and the fluctuation during the adjustment process are introduced.The analysis shows that the fluctuation of the settling material level is caused by the failure of the control of the spent catalyst slide valve.It is confirmed that the valve plate and valve stem have disengaged by dismantling the connecting block between the valve stem and the control mechanism,rotating and pulling the valve stem on site.By analyzing the connection structure of the valve stem,measures such as adjusting,rotating and pulling the valve stem are taken to restore the production of the device.A temporary top rod is installed by hot tapping in the 180°direction of the valve stem to jointly control the spent catalyst slide valve with the original valve stem,ensuring the long-term operation of the unit.To clarify the cause of the malfunction,a flow field simulation method is used to calculate the distribution of pressure clouds,fluid velocity,catalyst particle,and the control of blowing steam inside the slide valve.It is found that the flow control of blowing steam has a significant impact on the erosion corrosion at the connection point of the valve stem.This conclusion has been well validated during maintenance.