(487a) Effects of Oxygen Concentration and Coal Composition On Aerosol Chemistry in Oxy Firing

Oxy fired combustion is a technique used to facilitate the capture of a highly concentrated CO2 exhaust stream to enable efficient carbon sequestration. However, the effects of oxy firing in retrofit applications are not completely understood and must be investigated. In this study, the effect of oxy firing on particle size distribution, which was measured by SMPS, APS and then confirmed with gravimetric data from a low pressure impactor, was examined for three coals in two different combustion scenarios. The coals examined represent typical coals used across the United States and include a Powder River Basin (PRB) sub-bituminous, a Utah bituminous, and a high sulfur Illinois bituminous coal. The combustion scenarios represent two potential oxy firing methods. The first used 27% O2 and 73% once through CO2 to match heat flux, while the second scenario used 32% O2 and 68% CO2 in order to match the calculated adiabatic flame temperatures. Size segregated entrained aerosols from 0.030 to 15.7μm samples were collected with a low pressure impactor and then analyzed using ICP-MS to determine chemical composition. The effects of coal composition and oxy concentration are analyzed and compared to provide useful information to predict practical changes in aerosol concentration and composition under oxy fired retrofit applications.