旋转阀波纹管失效原因分析

Analysis of Failure Causes of Rotary Valve Bellows

旋转阀S-601 A/B是中国石化上海石油化工股份有限公司4^(#)芳烃吸附分离装置生产对二甲苯的核心设备,从2019年开始,发现B阀在运行中进出物料不平衡并有逐步扩大趋势,存在内漏现象,在2020年2月的检修中发现进料管波纹管已破损。通过金相和能谱等方式进行分析,发现失效原因为波纹管发生氯离子点蚀,在交变载荷作用下萌生疲劳裂纹,最终导致泄漏。

The rotary valve S-601 A/B is the core equipment for the production of p-xylene in the 4^(#)aromatics adsorption and separation unit of SINOPEC Shanghai Petrochemical Co.,Ltd.Starting from 2019,it was found that the B valve was unbalanced in and out of materials during operation with a gradually expanding trend due to internal leakage.The bellows of the feed pipe were found to be damaged during the maintenance in February 2020.Through metallographic and energy spectrum analysis,it is found that the failure cause is the pitting corrosion of chloride ions in the bellows,and fatigue cracks are induced under the action of alternating loads,which eventually leads to leakage.