Characterization of Particle Fluidization Pattern in a Gas Solid Fluidized Bed Based on Acoustic Emission (AE) Measurement

Abstract

Flow pattern of the fluidized bed is a key factor for heat transfer and the design of a new reactor. It is important to comprehend the fluidization conditions because the complex correlation between particle−particle and particle−environment in the reactor. In this study, we applied acoustic emission (AE) measurement in monitoring the particle fluidization pattern in a gas−solid bed fluidized with different sorts of particles classified by Geldart. With AE axial time average energy analysis, the flow structure of polyethylene particles was investigated both in the laboratory and plant apparatus. The results showed that the fluidization pattern in the bed is multicirculation, including the main-circulation zone, subcirculation zone, and the stagnant zone. Moreover, the influence of operating variables, such as particle size, superficial gas velocity, static bed height, and particle sorts had also been considered. It was found that the particle size, gas velocity, and particle sorts have significant impacts to the fluidization pattern. In contrast, the height of the stagnant zone did not show direct relation to the static bed height. AE measurement was proved to be reliable for understanding the dynamical features that affect the behavior of the fluidized bed. This can be useful guidance for an industrial process and help improve the process operation and the design of the new reactor.