Abstract: The reasons and solutions for the sudden rise and fluctuation of the settler material level from 41% during the adjustment process in a certain catalytic cracking unit are introduced. The analysis shows that the malfunction of the spent catalyst slide valve control caused the fluctuation of the settler material level. By removing the valve stem and control mechanism connecting block of the spent catalyst slide valve on-site, and adjusting measures such as rotating and pulling the valve stem, it is confirmed that the valve plate and valve stem are detached. Based on the analysis of the valve stem connection structure, measures such as adjusting the rotation and pulling of the valve stem were taken to restore the production of the device. A temporary top rod was installed on the 180° direction of the valve stem to work with the original valve stem to control the spent catalyst slide valve, ensuring the long-term operation of the device. In order to clarify the cause of the failure, a flow field simulation method was used to calculate the pressure cloud distribution, fluid velocity distribution, catalyst particle distribution, and control of the blowdown steam inside the slide valve. It was found that the flow control of the blowdown steam has a significant impact on the erosion at the valve stem connection. This conclusion was well verified during the maintenance.

Key words: font-family:-apple-system, blinkmacsystemfont, ", font-size:14px, background-color:#FFFFFF, ">FCCU, spent catalyst slide valve, valve stem detachment, eddy, wear, flow rate, erosion, simulation

摘要： 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。

关键词: font-family:-apple-system, blinkmacsystemfont, ", font-size:14px, background-color:#FFFFFF, ">催化裂化装置, 待生滑阀, 阀杆脱扣, 涡流, 磨损, 流速, 冲蚀, 仿真