Characterization of countercurrent liquid-upward and solid-downward fluidized system--颗粒学报PARTICUOLOGY

Zhang, E., Ma, K., Shao, Y., Zhu, J., & Nan, T. (2022). Characterization of countercurrent liquid-upward and solid-downward fluidized system. Particuology, 70, 95-105. https://doi.org/10.1016/j.partic.2022.01.009

Characterization of countercurrent liquid-upward and solid-downward fluidized system

Enming Zhang ^a, Keying Ma ^{b c}, Yuanyuan Shao ^{a c *}, Jesse Zhu ^b^a *, Tian Nan ^b

a School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
b Department of Chemical & Biochemical Engineering, Western University, London, Ontario N6A 3K7, Canada
c Institute of Shaoxing, Tianjin University, Zhejiang 312300, China

10.1016/j.partic.2022.01.009

Volume 70, November 2022, Pages 95-105

Received 2 September 2021, Revised 31 December 2021, Accepted 10 January 2022, Available online 19 January 2022, Version of Record 31 January 2022.

E-mail: yshao@tju.edu.cn; jzhu@uwo.ca

Highlights

• Variations of pressure drop with the operating conditions were investigated in detail.

• Two novel methods were proposed to identify flooding velocity in a countercurrent liquid–solid fluidized bed.

• Effects of device structure and operating conditions on solids holdup were studied.

• A modified Richardson–Zaki equation was established to predict the solids holdup.

Abstract

Acting as an operating mode of fluidization, the flow characteristics of a countercurrent liquid–solid fluidized bed (CCLSFB) were experimentally investigated using a Plexiglas column of 1.5 m in height. Countercurrent liquid-upward and solid-downward fluidization was achieved under a limited solid flowrate before flooding occurred.

The “flooding” phenomena and the flooding velocity were identified by measuring the variations in pressure drop in the axial direction of the column. Two different methods were used to quantify the flooding point that led to the instability of the system. Axial solids holdup profiles were also obtained from the pressure drop data along the column and the influences of device structure and operating conditions on the solids holdup were also studied. Seven types of particles with different diameters and densities were used. An agreement was found between the experimental results and the mathematic prediction derived from the Richardson–Zaki equation on the data of the solids holdup.

Graphical abstract

Keywords

Countercurrent fluidization; Flooding; Pressure drop; Solids holdup; Richardson–Zaki equation

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