Wenchao Gao1, Yifan Wang2, Hao Zhang2, Baoyu Guo1, Chenghang Zheng2, Jun Guo3, Xiang Gao 2, Aibing Yu1,4


ARC Research Hub for Computational Particle Technology, Department of Chemical Engineering, Monash University, Victoria 3800, Australia
State Key Laboratory of Clean Energy Utilization, State Environmental Protection Engineering Center for Coal-Fired Air Pollution Control, Zhejiang University, Hangzhou 310027, China
Fujian Longking Co., Ltd., Longyan 364000, China
Southeast University-Monash University Joint Research Institute, Suzhou Industrial Park, Jiangsu 215100, China


Received: November 5, 2019
Revised: December 21, 2019
Accepted: December 21, 2019
Download Citation: ||https://doi.org/10.4209/aaqr.2019.11.0609 

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Cite this article:

Gao, W., Wang, Y., Zhang, H., Guo, B., Zheng, C., Guo, J., Gao, X. and Yu, A. (2020). A Numerical Investigation of the Effect of Dust Layer on Particle Migration in an Electrostatic Precipitator. Aerosol Air Qual. Res. 20: 166-179. doi: 10.4209/aaqr.2019.11.0609.


HIGHLIGHTS

  • The effect of the dust layer on performance of ESP was investigated.
  • The thickness of the dust layer affected the electrical characteristics.
  • The impact of the dust resistivity on particle trapping was studied.
  • Some recommendations were presented to control dust thickness and resistivity.
 

ABSTRACT

Electrostatic precipitation processes have been widely applied to remove particulate matter from flue gases in coal-fired power stations. A high negative voltage is usually applied to a discharge electrode so that the gases are ionized in such processes. When the suspended particles in flue gases enter the ionized space, they are electrically charged and deposited on collection plates to form the layer of particle packing. However, the dust layer generally exists during the precipitation of charged particles on the collection plate. The negative effect of precipitated dust layer on the collection plate causes the collection efficiency of electrostatic precipitator (ESP) to deteriorate seriously due to some critical factors, such as dust resistivity and thickness of accumulated dust. In this study, a simulation method by computational fluid dynamics method was applied to investigate the particle collection performance of the ESP system with and without a dust layer. Also, the detailed electric parameters and particle capture performance in the 2D wire-plate electrode configuration were simulated. The results show that the voltage-current characteristics and detailed distribution of electric field and ion charge density are completely different under various dust resistivity conditions. The effect of the dust layer is significant, which causes collection efficiency to decrease sharply with the increasing thickness (1–5 mm) of the dust layer. Furthermore, results indicate that when particles with higher resistivity enter the ESP, their migration velocity decreases sharply. In the case of 80 kV, when the dust resistivity is 1012 Ω·cm, the decline rate of particle migration velocity reaches 57.7%. Meanwhile, useful suggestions were provided to reduce the effects of dust layers by regulating particle properties and designing dust removal systems.


Keywords: Dust layer; Electrostatic precipitator; Collection efficiency; Dust resistivity; Performance of decay



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