10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
Effects of Pressure and Coal Seams on the Characteristics of Coal Fly Ash and Submicrometer Particle Size Distribution
ZEHUA WANG, Zhichao Li, Shuhua Ma, Shili Zheng, Pratim Biswas, Washington University in St Louis
Abstract Number: 293 Working Group: Combustion
Abstract Coal combustion accounts for 33% of the total electricity generation in the US and both greater than 70% in China and India (Biswas et al. 2011; Wang et al. 2013). In addition, China, USA and India are the top three countries in coal consumption worldwide (Yao et al. 2015). As a result, large amounts of fly ash in the exhaust gas of coal combustors are collected at coal-fired power plants and poses challenges for appropriate disposal and re-utilization. In the meantime, large numbers of hazardous submicrometer particles are emitted to the ambient air due to their high penetration in conventional particle control devices. To effectively achieve either reuse or capture of fly ash, it is imperative to characterize fly ash using a holistic approach. Moreover, coal combustion is also one of the main source of carbon dioxide emission. The pressurized oxy-combustion, which can increase the efficiency and reduce the cost for the carbon dioxide capture and storage or utilization, is considered as a promising alternative to the traditional coal combustion (Gopan et al. 2014).
This study is focused on investigating the effects of pressure and coal seams on the characteristics of the coal fly ash and the submicrometer particle size distribution. Fly ash was produced by combustion of different coals from the US, India, and China in a lab-scale drop-tube furnace at different pressure. The submicrometer particle size distributions, mineralogy, and surface area of the generated fly ashes were characterized using a scanning mobility particle sizer (SMPS), x-ray diffraction (XRD), and Brunauer-Emmett-Teller (BET), respectively. The morphology and chemical composition were examined using a scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX). The results indicate that the US PRB coal fly ash was mainly composed of quartz, anhydrite, lime and hematite, while both India Chandrapur and China S02 coal fly ash were mainly composed of quartz and mullite. However, India Chandrapur coal fly ash had higher silicon content, while China S02 coal fly ash was rich in alumina. With an increase in pressure, the concentration of submicrometer particles was reduced. This study is meaningful to understanding the characteristics of coal fly ash generated from the pressurized combustion system, which can thus provide insights for more effective capture of submicrometer particles in pressurized particle collection devices.
References
Biswas, P., Wang, W.-N., An, W.-J. (2011). The energy-environment nexus: aerosol science and technology enabling solutions. Frontiers of Environmental Science & Engineering in China 5:299-312. Wang, X., Williams, B., Wang, X., Tang, Y., Huang, Y., Kong, L., Yang, X., Biswas, P. (2013). Characterization of organic aerosol produced during pulverized coal combustion in a drop tube furnace. Atmos. Chem. Phys 13:3345-3377. Yao, Z., Ji, X., Sarker, P., Tang, J., Ge, L., Xia, M., Xi, Y. (2015). A comprehensive review on the applications of coal fly ash. Earth-Science Reviews 141:105-121. Gopan, A., Kumfer, B. M., Phillips, J., Thimsen, D., Smith, R., Axelbaum, R. L. (2014). Process design and performance analysis of a Staged, Pressurized Oxy-Combustion (SPOC) power plant for carbon capture. Applied Energy 125:179-188.