Characterization of gas–liquid–solid fluidized beds by S statistics--颗粒学报PARTICUOLOGY

Arjmandi-Tash, O., & Zarghami, R. (2016). Characterization of gas–liquid–solid fluidized beds by S statistics. Particuology, 29, 135-142. https://doi.org/10.1016/j.partic.2016.02.003

Characterization of gas–liquid–solid fluidized beds by S statistics

Omid Arjmandi-Tash, Reza Zarghami ^*

Multiphase Systems Research Lab, Oil and Gas Processing Centre of Excellence, School of Chemical Engineering, College of Engineering, University of Tehran, P.O. Box 11155/4563 Tehran, Iran

10.1016/j.partic.2016.02.003

Volume 29, December 2016, Pages 135-142

Received 6 February 2015, Revised 23 January 2016, Accepted 15 February 2016, Available online 10 June 2016, Version of Record 18 November 2016.

E-mail: rzarghami@ut.ac.ir

Highlights

• Hydrodynamics of a gas–liquid–solid fluidized bed was investigated in state space domain.

• S statistics test on pressure signals of a gas–liquid–solid fluidized bed was applied.

• S statistics test revealed three transition velocities, and four distinct fluidization regimes.

• The test showed the effect of various operating conditions on the hydrodynamics in beds.

Abstract

The hydrodynamics of a gas–liquid–solid fluidized bed was investigated by applying the S statistics method to pressure fluctuations measured under various operating conditions in a laboratory-scale bed. S statistics tests reveal the existence of three transition velocities, especially at low gas velocities. Four distinct fluidization regimes, namely, the compacted bed, agitated bed and coalesced and discrete bubble regimes were detected. A comparison of reconstructed attractors of pressure fluctuations measured at different axial positions along the riser and with various solid loadings showed significant differences in the signals compared before fluidization, especially at minimum liquid agitation velocity. Close to the minimum liquid fluidization velocity and high liquid velocities, the variation in particle size has an insignificant effect on the bed hydrodynamics. Therefore, S statistics is a reliable method to demarcate different fluidization regimes and to characterize the influence of various operating conditions on the hydrodynamics of gas–liquid–solid fluidized beds. The method is applicable in large-scale industrial installations to detect dynamic changes within a bed, such as regime transitions or agglomeration.

Graphical abstract

Keywords

Gas–liquid–solid fluidized bed; Pressure fluctuation; Reconstructed attractor; S statistics; Transition velocity

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