Frequency Domain Analysis of Fluidized Beds with Vibration Time Series of the Bed Wall

Monitoring of fluidized beds operation is important in industrial applications. Collecting fluidize bed wall vibration is a non-intrusive method that can be used to characterize bed hydrodynamics. In the present work, the vibration of a lab-scale fluidized bed was measured at different operating conditions as well as the empty bed. It was shown that vibration of the empty bed is as significant as that of the fluidized bed. Therefore, the vibration signal was decomposed into two distinct signals, coherent and inherent signals. The inherent signal was used to reflect the bed hydrodynamics. The power spectral density of inherent vibration signal showed that the increasing aspect ratio of the bed leads to an increase in the intensity of vibrations especially at high frequencies. Moreover, there are first, second and so forth harmonics for which their intensities decrease as the frequency is increased.