Characterization of bubble behaviors in a dense phase pulsed gas–solid fluidized bed for dry coal processing--颗粒学报PARTICUOLOGY

Li, Y., Zhu, F., Zhang, Y., Zhao, Y., Zhang, G., Huang, Q., & Dong, L. (2020). Characterization of bubble behaviors in a dense phase pulsed gas–solid fluidized bed for dry coal processing. Particuology, 53, 83-91. https://doi.org/10.1016/j.partic.2020.01.002

Characterization of bubble behaviors in a dense phase pulsed gas–solid fluidized bed for dry coal processing

Yanjiao Li ^{a b}, Fenglong Zhu ^{a b}, Yadong Zhang ^{a b}, Yuemin Zhao a^b, Gansu Zhang ^b, Qingqing Huang ^c, Liang Dong ^{a b *}

a Key Laboratory of Coal Processing and Efficient Utilization, Ministry of Education, China University of Mining & Technology, Xuzhou 221116, Jiangsu, China
b School of Chemical Engineering & Technology, China University of Mining & Technology, Xuzhou 221116, China
c Department of Mining Engineering, West Virginia University, 1374 Evansdale Drive, Morgantown, WV 26506-6070, USA

10.1016/j.partic.2020.01.002

Volume 53, December 2020, Pages 83-91

Received 24 April 2019, Revised 19 January 2020, Accepted 23 January 2020, Available online 8 April 2020, Version of Record 16 December 2020.

E-mail: dongl@cumt.edu.cn

Highlights

• The bubble motions produced by two different particles in a bed were studied.

• The deformations of bubbles under different operating conditions were examined.

• A model to predict the velocity of bubbles in pulsed gas–solid fluidized bed is proposed.

Abstract

Pulsed gas–solid fluidized beds can effectively separate fine coal, and bubbles play an important role in creating suitable separation conditions. The present study performed statistical and image analyses of the evolution of bubbles in a two-dimensional pulsed gas–solid fluidized bed using a high-speed dynamic camera. The effects of apparent gas velocity, pulsation frequency and particle size on bubble characteristics and bed expansion were analyzed. The results indicate that, when a fluctuation frequency is added, the expansion height of the bed increases, the effect of attachment to the bed wall decreases, the leading diameter and rising velocity of the bubbles both decrease and the degree of bubble deformation increases. These trends are also more obvious for fine particles. These findings demonstrate that a high density pulsed gas–solid fluidized bed can effectively combine gases and solids to produce a uniform, stable mixture. The bubble diameter and rising velocity were also simulated in the present work, and the relationship between the two was established using a fitting model with an error within 5%. This model provides an effective means of predicting bubble velocity as well as studying the distribution of the bubble phase and improving the stability of the bed density.

Graphical abstract

Keywords

Apparent gas velocity; Pulsation frequency; Bubble diameter; Rising velocity; Deformation degree; Fluidized bed

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