By Lital Yinon
Advisors: Prof. Nickolas J. Themelis, Earth and Environmental Engineering and Prof. V. Faye McNeill, Chemical Engineering
Department of Earth and Environmental Engineering
Fu Foundation School of Engineering & Applied Science
Combustion processes are the dominant anthropogenic sources of particulate matter emissions to the atmosphere. Recently, special attention has been directed to the potential health effects of ultrafine particles (UFP) of diameters less than 0.1μm. Numerous research studies show that inhalation exposure to UFP can lead to exacerbation of lung and cardiovascular diseases and that the effect is more severe than that of fine and coarse particles. It has also been shown that UFP can generate more reactive oxygen species (ROS) than larger particles and are able to cross epithelial cells and translocate to extrapulmonary organs.
In the combustion of coal, biomass, and municipal solid wastes, UFP mainly form by nucleation of metal vapor followed by growth through coagulation and condensation of other vaporized materials. Some of these particles are not captured in the air pollution control (APC) and are emitted to the atmosphere with the treated flue gas. UFP emissions from stationary combustion sources, in general, and from waste‐to-energy (WTE) plants, in particular, are not well characterized as yet.
This study included a critical analysis of the literature with the objective to quantify the number concentration of UFP emitted from WTE facilities in comparison to coal and biomass power plants. Analysis of fly‐ash samples from coal burned in laboratory combustors has shown that the ultrafine fraction contained higher concentrations of volatile metals, in some cases 50 times higher, than in fine and coarse particles. This supports the idea that volatile and semi‐volatile metals in the fuel vaporize and nucleate to form UFP.
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