Author's School

School of Engineering & Applied Science

Author's Department/Program

Energy, Environmental and Chemical Engineering

Language

English (en)

Date of Award

January 2009

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Chair and Committee

Pratim Biswas

Abstract

Energy is the issue of great importance at the present. Coal, the cheapest and the most abundant reserve fossil fuel, is currently one of the most widely used energy source globally and will continue to be in the foreseeable future. The use of coal has also posed many world-wide environmental challenges, including the control of particulate matter, mercury, and trace metals, and carbon oxide: CO2) emissions. The rising of CO2 level in the atmosphere due to burning of fossil fuels is one of the major factors contributing to the global climate change. Capturing CO2 from coal combustion exhaust has been receiving significant attention; however, the volume fraction of CO2 in conventional coal combustion system: with air) ranges only 13%-15%, making it difficult to cost-effectively design the systems. Oxy-coal combustion or O2/CO2 recycled coal combustion is one of the promising techniques to overcome the limitation of low CO2 concentration in the exhaust. Before this technology can be employed, the effects of oxy-coal combustion on the pollutants associated with coal combustion, including fine particle, gaseous mercury and heavy metal emissions, need to be established. In addition, the influences of oxy-coal combustion on the performance of the current pollution control technologies, such as an electrostatic precipitator: ESP), need to be addressed. This dissertation investigated two aspects of coal combustion process:: 1) pollutant formation, specifically submicrometer particles and mercury, and: 2) pollutant control. The first part of dissertation addresses the impact of oxy-coal combustion on the formation submicrometer particles and the speciation of gaseous mercury. The second part focuses on the performance of two pollutant control technologies, including an ESP for capturing submicrometer particles and nano-structured TiO2 with UV irradiation for mercury capture. The findings presented here can be broadly divided into three parts. The first part reports the influence of oxy-coal combustion on submicrometer particle formation and capture using an ESP. The second part addresses the impacts of oxy-coal combustion on mercury speciation. The third part investigates the performance of nano-structured sorbent for capturing mercury and controlling heavy metal emissions from combustion process. The findings presented here can be used as a guideline for proper operation and control of pollutants generated from both oxy-coal and conventional combustion systems.

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Permanent URL: http://dx.doi.org/10.7936/K7KD1W0S

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