乙烯装置急冷油泵机械密封故障分析及处理

Mechanical seal failure analysis and treatment of quench oil pump in ethylene unit

新建成乙烯装置投产的一年时间里,5台急冷油泵机械密封陆续出现泄漏问题,通过拆检泄漏的机械密封,发现密封面有焦粉,焦粉导致密封面磨损失效。从操作条件、设计选型、机械密封构造等方面进行深入分析,发现主要是由于冲洗油冲洗流道设计不合理导致冲洗油未能在机械密封前形成有效隔离液,介质中焦粉容易进入机械密封,造成机械密封面磨损和波纹管弹簧受限而失效。通过改变冲洗油流道使冲洗油起到真正保护机械密封的作用,从而有效解决急冷油泵机械密封经常性泄漏问题。

During the one year since the new ethylene unit was put into operation,the mechanical seals of 5 quench oil pumps had leakage problems one after another.After disassembling and inspecting the leaked mechanical seals,it was found that there was coke powder in the sealing area,which led to the wear and failure of the sealing surface.Through in-depth analysis on operating conditions,design selection and mechanical seal structure and other aspects.It is found that the main reason is that the flushing oil fails to form an effective isolation liquid before the mechanical seal requiring flushing protection due to the unreasonable design of the flushing oil flushing channel,and the coke powder in the medium is easy to enter the mechanical seal,resulting in the wear of the mechanical seal surface and the failure of the bellows spring.By changing the flushing oil flow path,the flushing oil can truly protect the mechanical seal,thus effectively solving the problem of frequent leakage of mechanical seal of quench oil pump.