Analysis of the chaotic dynamics of a high-flux CFB riser using solids concentration measurements--颗粒学报PARTICUOLOGY

Manyele, S. V., Zhu, J.-X., Khayat, R. E., & Pärssinen, J. H. (2006). Analysis of the chaotic dynamics of a high-flux CFB riser using solids concentration measurements. China Particuology, 4(3), 136–146. https://doi.org/10.1016/S1672-2515(07)60253-X

Analysis of the chaotic dynamics of a high-flux CFB riser using solids concentration measurements

S.V. Manyele ^a, J.-X. Zhu ^a *, R.E. Khayat ^b, J.H. Pärssinen ^a

a Department of Chemical and Biochemical Engineering, University of Western Ontario, London, ON, N6A 5B9, Canada
b Department of Mechanical and Materials Engineering, University of Western Ontario, London, ON, N6A 5B9, Canada

10.1016/S1672-2515(07)60253-X

Volume 4, Issues 3–4, July 2006, Pages 136-146

Received 20 December 2005, Accepted 12 April 2006, Available online 27 November 2007.

E-mail: zhu@uwo.ca

Highlights

Abstract

A high-flux circulating fluidized bed (CFB) riser (0.076-m I.D. and 10-m high) was operated in a wide range of operating conditions to study its chaotic dynamics, using FCC catalyst particles (d_p = 67 μm, ρ_p = 1500 kg·m⁻³). Local solids concentration fluctuations measured using a reflective-type fiber optic probe were processed to determine chaotic invariants (Kolmogorov entropy and correlation dimension). Radial and axial profiles of the chaotic invariants at different operating conditions show that the core region exhibits higher values of the chaotic invariants than the wall region. Both invariants vary strongly with local mean solids concentration. The transition section of the riser exhibits more complex dynamics while the bottom and top sections exhibit a more uniform macroscopic and less-complex microscopic flow structure. Increasing gas velocity leads to more complex and less predictable solids concentration fluctuations, while increasing solids flux generally lowers complexity and increases predictability. Very high solids flux, however, was observed to increase the entropy.

Graphical abstract

Keywords

high-flux riser; concentration fiber optic probe; chaos analysis; correlation dimension; Kolmogorov entropy

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