中文摘要：

对正常停产按操作规程停泵后,出现重烷基苯供料泵泵盖崩开,泵出口压力表因超量程损坏现象进行了分析。通过排查管线,测量重烷基苯密度随温度的变化,计算重烷基苯热膨胀系数后发现问题所在：输出管线内重烷基苯加热后体积膨胀,管内压强增大,泵出口阀关闭不严,致使泵体压强升高,泵损坏。提出了两种解决方法：停泵后放出计算量的液体或在输出管线上加安全阀。

英文摘要：

A heavy- alkylbenzene （HAB） feed pump was shut down in accordance with the normal operating rules. However, under such normal conditions, the pump casing broke and the pressure gage at the discharge end of the HAB pump damaged due to the pressure to be measured was beyond the rated pressure range of the pressure gage. Such phenomena showed that the pump casing has been over pressurized. In order to find the reason of such over-pressure phenomenon, a thorough study with respect to the whole system as well as the physical - chemical properties of working medium, including the troubleshooting of the pump and the concerning piping as well as measurement of the density - temperature profile and the calculation of thermal expansion coefficient of HAB,was carried out. Results showed that this problem is due to the expansion of the HAB liquid in the pump discharge piping system caused by temperature rise;while the block valve at the discharge end of the pump was not tightly closed. Then the expanded HAB liquid flowed into the pump, and caused the over - pressurizing of the pump casing. Two ways were suggested for avoiding the re - happening of such failure. One is during the shut down of the pump, a calculated amount of the HAB liquid should be drained out. Another way is to install a pressure relieve valve at the HAB pump discharge piping.