Experimental investigations of granular shape effects on the generation of electrostatic charge--颗粒学报PARTICUOLOGY

Yao, J., Wu, J., Zhao, Y., Lim, E. W. C., Cao, P., Zhou, F., Wang, C.-H., & Li, N. (2014). Experimental investigations of granular shape effects on the generation of electrostatic charge. Particuology, 15, 82–89. https://doi.org/10.1016/j.partic.2013.01.010

Experimental investigations of granular shape effects on the generation of electrostatic charge

Jun Yao^a *, Jiejie Wu ^a, Yanlin Zhao ^b, Eldin Wee Chuan Lim ^c, Peigen Cao ^a, Fang Zhou ^a, Chi-Hwa Wang ^c, Ning Li ^a

a School of Energy Research, Xiamen University, Xiamen 361005, China
b College of Mechanical & Transportation Engineering, China University of Petroleum, Beijing 102249, China
c Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore 117576, Singapore

10.1016/j.partic.2013.01.010

Volume 15, August 2014, Pages 82-89

Received 21 October 2012, Revised 28 December 2012, Accepted 5 January 2013, Available online 25 June 2013.

E-mail: yaojun@xmu.edu.cn

Highlights

• Dependence of electrostatic charge generation on particle shape was investigated.

• PVC granules with the shape of triangle or trapezium were studied.

• Granule orientation, aspect-ratio, sliding area/distance and relative humidity were considered.

• Electrostatic charge increased with aspect-ratio and sliding area, but decreased with humidity.

Abstract

In solid processing systems, electrostatic problems are commonly observed for granules of various shapes. However, a complete understanding of the basic dependence of electrostatic charge generation on particle shape has yet to be established. This observation motivated the present study on examining the effect of granular shape on electrostatics. In this study, polyvinyl chloride (PVC) granules (diameter 1.1–4.1 mm, in the shape of a triangle or trapezium) were first discharged to remove any residual charges and subsequently their electrostatic charging characteristics were studied by allowing a granule to slide along a pipe wall. Several factors such as granular front-facing angle, length-ratio, sliding area, sliding orientation, sliding times, and relative humidity were considered when studying their effects on the electrostatic charging of granules. It was found that triangular granules with smaller front-facing angles tended to generate more electrostatic charge. The amount of electrostatic charge increased with granular length-ratio and sliding area but decreased with humidity. In addition, granular sliding in the orientation of the front-facing angle (for triangular granules) or the short side (for trapezoidal granules) generated more electrostatic charge than that in the orientation of the long side. For both granule shapes, the electrostatic charge increased with granular sliding times and reached a saturated state after around 8–9 sliding movements. The saturated electrostatic charge increased with either granular length ratio or sliding area.

Graphical abstract

Keywords

Granule; Electrostatic charge; Shape; Triangle; Trapezium

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