LNG接收站高压外输泵异响故障分析

某LNG接收站运行不到2 a,1台高压外输泵运行过程中出现异响、振动烈度增大,严重影响到生产安全。为解决该问题,建立了故障树,分析故障可能来自泵本体结构、泵体紧固件、汽蚀、部件磨损、工艺匹配性以及泵筒是否憋压这6个方面。通过逐一排查,认为异响是由泵零部件磨损造成的可能性最大。进一步对泵振动信号进行了频谱分析以验证所作的判断,发现故障发生时3倍频、2倍频、基频及以下能量明显增大,符合泵零部件磨损故障特征。解体发现泵口环、扩散器、泵轴等磨损严重,其根本原因是由于泵入口过滤器选型不当导致。

Fault analysis for abnormal sound of HP sent-out pump in LNG receiving terminal

The increases of abnormal noise and the pump vibration amplitude were detected in the operation of a high pressure sent-out pumps (HP pumps) at a LNG receiving terminal which has been in operation for less than two years.This problem has seriously affected the production safety.To solve this problem,a fault tree was established,which found that six culprits may have caused fault,i.e.pump structure,pump parts fastening condition,cavitation,component wearing,process matching and pump pressure build-up.The one by one analysis concludes that the wearing of pump parts is the cause of the abnormal noise.To confirm this judgment,the spectrum was used to analyze the pump vibration signal.It is also found that when failure occurs,the frequency energy of 3x,2x,1x and below would increase,and the results were consistent with fault characteristics.Severe wearing of the pump inlet rings,diffusers and pump shaft were found in disassembly,and the root cause is the improper selection of the pump inlet filter.