蜡油加氢装置液力透平密封失效分析

Analysis of mechanical seal failure in hydraulic turbine in wax oil hydrotreating unit

总结了某炼化公司3.2 Mt/a蜡油加氢装置液力透平机械密封的故障情况,通过对密封结构型式、密封冲洗管路、密封维修和设备操作维护等多方面的分析,发现密封本身结构存在缺陷,密封冲洗系统也存在问题。提出了密封改造措施：改为3CW-FF型式、采用小弹簧作为补偿元件、补偿元件改为静止部件、升级动静环材质等;同时更换密封冲洗系统隔离液、改善管路布置方式、提高冷却水水质及机械密封大气侧增加氮气保护等,并提出了设备维护运行中需要注意的问题。改进后的机械密封应用在加氢裂化装置液力透平后,运行效果良好,密封腔压力通过补压能维持在3.2 MPa,隔离液冷却后温度基本在70~75℃,同步运行率达到100%。

In this paper,the failure of the mechanical seals in hydraulic turbines installed in a petrochemical plant is summarized and analyzed. The analysis on the seal construction,external seal flush systems,seal repair and equipment maintenance found that there were defects in seal construction and flush system.The improvement measures were proposed for the seal such as using 3CW-FF type,adopting small spring as compensation element,using compensation element as static component,improving the material of seal rings,etc. At the same time,other improvements should be made,such as changing spacer fluid of the flush system,improving the piping layout,improving the quality of the cooling water and using nitrogen protection for the air side of mechanical seal. Precautions were recommended in equipment maintenance and operation. The hydraulic turbine in hydrocracking unit has been operating very smoothly after the application of the improved mechanical seal the pressure of seal chamber is 3. 2 MPa via additional pressure,the temperature of spacer fluid is 70 ~ 75 ℃ after cooling,and the synchronized running rate is 100%.