Effects of kaolin-limestone blended additive on the formation and emission of particulate matter: Field study on a 1000 MW coal-firing power station

Xiaowei Liu; Yishu Xu; Jiuxin Qi; Hao Wang; Tianpeng Zhang; Minghou Xu

doi:10.1016/j.jhazmat.2020.123091

Effects of kaolin-limestone blended additive on the formation and emission of particulate matter: Field study on a 1000 MW coal-firing power station

J Hazard Mater. 2020 Nov 15:399:123091. doi: 10.1016/j.jhazmat.2020.123091. Epub 2020 Jun 4.

Authors

Xiaowei Liu¹, Yishu Xu², Jiuxin Qi¹, Hao Wang¹, Tianpeng Zhang¹, Minghou Xu¹

Affiliations

¹ State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Luoyu Road 1037, Wuhan, 430074, China.
² State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Luoyu Road 1037, Wuhan, 430074, China; School of Energy and Power Engineering, Huazhong University of Science and Technology, Luoyu Road 1037, Wuhan, 430074, China. Electronic address: xuyishu@hust.edu.cn.

PMID: 32534400
DOI: 10.1016/j.jhazmat.2020.123091

Abstract

Effects of a blended additive made of kaolin and limestone on the formation and emission characteristics of particulate matter (PM) was discussed for the first time. Systemic characterizations on the concentration, size distribution, elemental composition, micromorphology, specific resistivity of the PM were performed. Results revealed that the blended additive diminished the mass concentrations of the ultrafine PM and PM_2.5 out of the furnace by 29.77 % and 40.91 % respectively. Interestingly, the additive also significantly reduced coarse PM, with the reduction efficiency for PM in 0.3-1 μm of ∼43 %. The additive captured the mineral vapors and thereby suppressed their migration into the ultrafine PM. Well, interactions among additive and ash promoted melting of the additive/ash particles. This improved the scavenging of both ultrafine and coarse PM via the liquidus capture mechanism. After the electrostatic precipitators (ESPs), emission of the ultrafine PM slightly increased after adding the additive because of the increasing of the specific resistivity of the ash particles and the reduction of electronegative gas (e.g., SO₂) in the ESPs. The emission of total PM_2.5 decreased by 32.31 % as less fly ash entering ESPs. Additionally, the leaching behaviours of heavy metals Cr, Mn, As and Pb in the fly ash were investigated.

Keywords: Additive; Coal combustion; Kaolin; Limestone; Particulate matter.

Publication types

Research Support, Non-U.S. Gov't