AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
Establishing the Role of Sulfur in Coal in Aerosol (Sulfuric Acid, Sulfate and Organic) Formation during Pulverized Combustion in a Drop-tube Furnace
XIAOFEI WANG, Brent Williams, Pratim Biswas, Washington University in St. Louis
Abstract Number: 271 Working Group: Combustion
Abstract Pulverized coal combustion is widely used for electricity and heat generation. However, it results in the production of large quantities of air pollutants, including particulate matter. It is well known that sulfuric acid particles are formed in flue gas from coal combustion. However, there are very few (or no) studies establishing the pathway and role of transformation of the sulfur in coal. We report the presence of sulfuric acid on the surface of fly ash particles produced by PRB coal combustion in a drop-tube furnace, even those fly ash particles that are strongly basic. This probably indicates that the reaction of sulfuric acid and basic metal oxides in fly ash particles are slow, probably due to the low diffusion rate of sulfuric acid into particles. Using a high-resolution time-of-flight aerosol mass spectrometer, organic species were found to be internally mixed with sulfuric acid and sulfate. By varying the sulfur content, total concentrations of sulfuric acid and sulfate in flue gas particulate matter were changed. It was found that there was a strong correlation between organic and sulfuric acid/sulfate formation. The mechanism is investigated and proposed: sulfuric acid and sulfate may play an important role in covering and protecting organic species in particulate matter from oxidation in the environment with high temperature and high oxygen concentration. Organic composition of the aerosol was further characterized in detail using a thermal desorption aerosol gas chromatograph (TAG).