Analysis of Gamma-Ray Imaging Data to Describe Hydrodynamic Properties of Gas-Polyethylene Fluidized Beds

Zarabi, T. and Kantzas, A.

DOI: 10.1002/cjce.5450780501
Canadian Journal of Chemical Engineering, 78(5), October 2000, Pages 849-857.


A scintillation gamma camera was used for measuring the instantaneous velocity profile and average velocity as well as the trajectories of a radioactive particle in small laboratory scale air–polyethylene–fluidized beds. A large number of frames, with frequencies between 1 and 50 Hz, were analyzed to investigate the effects of bed height, gas velocity and particle morphology. Subsequently: (1) horizontal and axial variations of the particle velocity were found; (2) three different flow zones along the axis (i.e., entrance zone, circulation zone and free board) were quantified; and (3) a characteristic time and a new definition of circulation (cycle) period were introduced. It was also found that the particle sometimes oscillates in the free board or gets trapped in the entrance zone.

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