流化床声发射机理及其在故障诊断中的应用

引　言流化床反应器能否长期稳定运行是一个十分严重的挑战 ,如果不彻底掌握流化质量的控制规律 ,对诸如强放热聚合反应过程 ,床层中流化粒子易于聚集、结块 ,甚至导致流化床崩溃而被迫停车 .因此 ,流化床故障诊断一直是工业界和学术界共同面临的难题 .流化系统一旦出现故障就会有反映流动规律本质的特征物理量出现较大变化以至突变 ,只是有些物理量对这些变化存在空间或时间上的不敏感性 .如压力信号就存在时间上的不敏感性 ,即往往压力信号出现显著变化时 ,床层流化质量已无法通过改变操作条件来改善 ;而光纤测量则存在空间上的不敏感性 ,…

MECHANISM OF ACOUSTIC EMISSIONS AND ITS APPLICATION ON DIAGNOSIS OF MALFUNCTION IN FLUIDIZATION

Diagnosis of malfunction in fluidized beds is always a very difficult problem for a long time in academic circles and industrial circles. In this paper,we use acoustic sensor to measure the passive acoustic emissions (AE) from a bubbling fluidized bed.By comparison between acoustic and pressure signals,we found that acoustic signals are very sensitive to large particles such as agglomeration and particle sintering occurred in the bed and so on.Analysis of AE mechanism shows that AE measurement mainly stems from particle-chamber collisions and friction.AE measurements are completely non-intrusive and are not subject to erosion, corrosion, or plugging.Therefore, study and measurement of AE in different fluidization conditions will provide many new methods and trains of thought for detecting early deterioration of the fluidization quality.