10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
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Comparison of Charge Fraction and Electrostatic Precipitation of Fly Ash from Combustion of India, US and China Coal Seams
ZHICHAO LI, Pratim Biswas, Washington University in St Louis
Abstract Number: 289 Working Group: Control and Mitigation
Abstract Fly ash in coal combustion exhaust gas is a major source of fine particulate matter in atmosphere in India, US and China, whose coal consumption accounts for more than 70% of world coal use (EIA 2016). In addition, fine particles have much higher tendency to escape common particle control equipment and discharge into the atmosphere. To better understand fine particle formation in coal combustion and more effectively control particle emission, it is imperative to explore the characteristics of fly ash from the combustion of coal seams widely used in different countries and their impacts on particle removal.
Electrostatic precipitator (ESP) is regarded as one of the most popular industrial particle emission control technology due to its high mass collection efficiency, capability to collect particles with diverse composition and long-term reliability. It needs to be noted that fly ash particles in combustion exhaust gas have been reported catching significant amount charges (Maricq 2004; Suriyawong et al. 2008), which might influence the particle charging process in the ESP and its capture performance (Li et al. 2016). These findings indicate that knowing charging status of fly ash is informative for better design and control of ESPs.
This study experimentally examined the size distribution, charged fraction and resistivity of fly ash from the combustion of coal from India, US, and China. The penetration of particles in a lab scale cylindrical ESP as a function of size was also measured. Because the capture efficiency is governed by complex non-linear relations, a machine learning regression method was employed to predict the capture efficiency of ESP with particle size, number concentration, applied voltage, ash resistivity, charged fraction as input variables. This work will provide novel insights for ESP modeling, design and operation.
References
EIA, U. E. I. A. (2016). International energy outlook 2016.
Maricq, M. (2004). Size and charge of soot particles in rich premixed ethylene flames. Combustion and Flame 137:340-350.
Suriyawong, A., Hogan, C. J., Jr., Jiang, J., Biswas, P. (2008). Charged fraction and electrostatic collection of ultrafine and submicrometer particles formed during O2-CO2 coal combustion. Fuel 87:673-682.
Li, Z., Jing, H., Biswas, P. (2016). Capture of submicrometer particles in a pressurized electrostatic precipitator. Aerosol Sci. Technol. 50:1115-1129.