Particle clustering (mesoscale structure) of high-flux gas–solid circulating fluidized bed--颗粒学报PARTICUOLOGY

Wang, C., Li, C., Lan, X., Wu, Y., & Gao, J. (2020). Particle clustering (mesoscale structure) of high-flux gas–solid circulating fluidized bed. Particuology, 48, 144-159. https://doi.org/10.1016/j.partic.2018.12.003

Particle clustering (mesoscale structure) of high-flux gas–solid circulating fluidized bed

Chengxiu Wang, Chengxiang Li, Xingying Lan, Yingya Wu, Jinsen Gao ^*

State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249, China

10.1016/j.partic.2018.12.003

Volume 48, February 2020, Pages 144-159

Received 12 July 2018, Revised 14 November 2018, Accepted 16 December 2018, Available online 1 May 2019, Version of Record 27 January 2020.

E-mail: jsgao@cup.edu.cn

Highlights

• Experimental and modeling researches on particle-clustering phenomenon in HFCFBs were reviewed.

• Experimental techniques and results of particle clustering in HFCFBs were discussed.

• Modeling of clustering with Eulerian–Eulerian and Eulerian–Lagrangian approaches were summarized.

Abstract

Particle clustering is an important dynamic phenomenon in circulating-fluidized-bed (CFBs) systems, and has been suggested as a key contributing factor to the non-uniform hydrodynamics of CFBs. Studies show that particle clusters can be affected by solids flux, in terms of frequency, duration, and solids holdup. To understand the characteristics of particle clusters under high-solids-flux conditions, experimental and modeling studies in high-solids-flux gas–solids CFBs were reviewed and summarized. Optical and electrical measurements and imaging methods were used to monitor the particle-clustering phenomenon in CFBs. Particles were found to cluster in high-flux CFBs, and were characterized by a denser cluster-solids holdup and a shorter time fraction, which was different from the behavior in low-flux CFBs. Particle properties affected particle clustering in high-flux CFBs significantly. In modeling work, Eulerian–Eulerian and Eulerian–Lagrangian methods were used to study the particle-cluster characteristics. Good results can be obtained by using the Eulerian–Eulerian method to simulate the CFB system, especially the high-flux CFBs, and by considering the effects of particle clusters. The Eulerian–Lagrangian method is used to obtain detailed cluster characteristics. Because of limits in computing power, no obvious results exist to model particle clusters under high-solids-flux conditions. Because high-solids-flux conditions are used extensively in industrial applications, further experimental and numerical investigations on the clustering behavior in HF/DCFBs are required.

Graphical abstract

Keywords

High-flux; Circulating fluidized bed; Mesoscale structure; Particle cluster; Numerical simulation; Gas–solids hydrodynamics

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