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Partic. vol. 40 pp. 80-87 (October 2018)
doi: 10.1016/j.partic.2017.10.006

Capture efficiency of coal/biomass co-combustion ash in an electrostatic field

Jianyi Lua,*, Lili Fua, Ximei Lia, Eric Eddingsb

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lujianyi@tsinghua.org.cn

Highlights

    • The ratio of 14C/12C in co-ash samples were used to identify the origin of each ash component. • Co-ash could be efficiently captured using an electrostatic precipitator (ESP). • Biomass addition assisted with the removal of both coal ash and biomass ash in ESP.

Abstract

Ash samples from corn stalk and coal co-fired at 0%, 5%, 10%, 15%, 20%, and 100% biomass were collected by a 4-stage wire-pipe type electrostatic precipitator (ESP), and the ratio of 14C/12C in ash samples from the 0%, 20%, and 100% co-firing scenarios were measured by an accelerator mass spectrometer. The differential capture efficiency in electrostatic fields for coal ash, coal/biomass co-combustion ash (co-ash), and pure biomass ash was studied separately based on the ratio 14C/12C. Other factors that may influence capture efficiency were analyzed, including microscopic morphology, resistivity, dust density, and particle size distribution. The results indicate that co-ash may be efficiently captured by ESP, while pure biomass ash could not. Co-ash capture was mainly concentrated in the first two electrostatic fields in the lab-scale ESP, and the overall capture efficiency exceeded 90%. Biomass addition decreased the resistivity of co-ash, and enhanced its surface adsorption capacity to form agglomerates, facilitating the capture of co-ash. The capture efficiency of coal ash in co-ash was higher than that of pure coal ash in the first electrostatic field of the ESP. Co-firing biomass can aid the removal of both coal ash and biomass ash when using an ESP.

Graphical abstract

Keywords

Biomass; Co-combustion ash (co-ash); Capture efficiency; Electrical field; 14C/12C