Collection efficiency in a three-dimensional randomly arranged dual-layer granular bed filter--颗粒学报PARTICUOLOGY

Chen, J., Li, X., Huai, X., & Zhou, J. (2020). Collection efficiency in a three-dimensional randomly arranged dual-layer granular bed filter. Particuology, 49, 88-94. https://doi.org/10.1016/j.partic.2018.11.006

Collection efficiency in a three-dimensional randomly arranged dual-layer granular bed filter

Junlin Chen^{a b}, Xunfeng Li ^{a b *}, Xiulan Huai ^{a b *}, Jingzhi Zhou ^{a b}

a Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing 100190, China
b University of Chinese Academy of Sciences, Beijing 100049, China

10.1016/j.partic.2018.11.006

Volume 49, April 2020, Pages 88-94

Received 15 May 2018, Revised 21 October 2018, Accepted 2 November 2018, Available online 3 June 2019, Version of Record 26 February 2020.

E-mail: lixunfeng@iet.cn; hxl@iet.cn

Highlights

• Collection efficiency is better for dual-layer than for single-layer granular beds.

• Inlet gas velocity affects grade collection efficiency less for dual-layer granular bed.

• St threshold shifts forward as bed depth of lower layer of fine granules increases.

Abstract

The dual-layer granular bed filter packed with randomly arranged granules was simulated to study the effects of bed depth of the lower layer of fine granules and the inlet gas velocity on the collection mechanism. The computational results show that the collection efficiency is much better from this granular bed than a single-layer granular bed, especially for particle diameters of 1–10 μm. The inlet gas velocity has less effect on the grade collection efficiency of the dual-layer granular bed than of the single-layer granular bed. The dual-layer granular bed provides a high collection efficiency and low pressure drop. The relationship between the grade collection efficiency and the Stokes number (St) based on the inlet gas velocity is obtained. If St is below a threshold, the grade collection efficiency remains stable; if St is in value above threshold, the grade collection efficiency increases linearly with lg(St). As the bed depth of the lower layer of fine granules increases, the threshold for St shifts forward.

Graphical abstract

Keywords

Dual-layer granular bed filter; Pressure drop; Grade collection efficiency; Stokes number

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