Circulating turbulent fluidization—A new fluidization regime or just a transitional phenomenon--颗粒学报PARTICUOLOGY

Zhu, J. (2010). Circulating turbulent fluidization—A new fluidization regime or just a transitional phenomenon. Particuology, 8(6), 640-644. https://doi.org/10.1016/j.partic.2010.08.008

Circulating turbulent fluidization—A new fluidization regime or just a transitional phenomenon

Jesse Zhu^*

Particle Technology Research Centre and Department of Chemical and Biochemical Engineering, University of Western Ontario, London, Ontario, N6A 5B9, Canada

10.1016/j.partic.2010.08.008

Volume 8, Issue 6, December 2010, Pages 640-644

Received 30 June 2010, Accepted 31 August 2010, Available online 2 November 2010.

E-mail: jzhu@uwo.ca

Highlights

Abstract

While circulating fluidized bed (CFB) reactor has many advantages over the more conventional turbulent fluidized bed (TFB) reactor, it does at least have one significant shortcoming—the rather dilute solids volume concentration in CFB reactor gives rise to less ideal reaction intensity. On the other hand, while having higher reaction intensity, TFB reactor has one fatal drawback of particle back-mixing, making it not suitable for certain reactions such as catalytic reaction where the catalyst requires frequent regeneration. This paper describes some key issues in the development of a circulating turbulent fluidized bed (CTFB) reactor that combines the advantages of both TFB and CFB, that is, to have the high reaction intensity as in TFB but and also to have a suppressed solids back-mixing as in CFB due to a continuous net upflow of solids flux through the bed. Experimental results show enough evidence to suggest that a new fluidization regime is formed, the characteristics of which appears to be distinct from those observed in a regular TFB and from those in either the bottom or the upper sections of regular CFB and/or high-density CFB (HDCFB). Fundamentally, the difference is that particle–particle interaction (collision) dominates the motion of particles in CTFB and TFB, while gas–particle interaction (drag force) is the key element that determines the two phase flow in CFB including HDCFB.

Graphical abstract

Keywords

Circulating-turbulent fluidized bed; Flow regime; Circulating-turbulent fluidization; Turbulent fluidized bed; Circulating fluidized bed

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