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

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 (14)c/C-12 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 C-14/C-12. 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. (C) 2018 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.