气相法聚乙烯流化床反应器中冷凝操作模式的声发射检测

在Unipol气相法乙烯聚合装置中,对流化床反应器切换到冷凝操作模式的过程进行声发射检测试验。当循环气体中冷凝液出现且含量逐渐增加时,声发射信号在175～200kHz特征频域内的能量分率(R)发生突变并持续增大。据此,提出以R发生突变并持续增大作为流化床反应器切换到冷凝操作模式的判据。工业试验结果表明,可利用声发射技术检测流化床反应器是否进入冷凝操作模式,且比传统的温差判别方法更为灵敏。

Measurement of Condensation Mode Operation in Polyethylene Gas Fluidized Bed Reactor by Acoustic Emission Technique

Procedure of switching into condensation mode operation of gas fluidized bed reactor in Unipol gas-phase ethylene polymerization plant was monitored by acoustic emission technique.It was found that along with appearing of liquid in recycle gas and the following increasing of liquid amount,the energy ratio(R) of acoustic emission signals in characteristic range from 175 to 200 kHz displayed a sudden change followed by continuous rising of R.Thus,the sudden change and the continuous rising of R could be considered as vigorous criterion to monitor condensation mode operation.Industrial practice showed that the acoustic emission technique was effective on monitoring condensation mode operation,and was more sensitive than traditional criterion by means of temperature difference.