The characteristics of particulate matter (PM) emitted from residual fuel oil combustion in two different types of combustion equipment were compared. A small commercial 732 kW rated fire-tube boiler yielded a weakly bimodal particulate size distribution (PSD) with over 99% of the mass contained in a broad coarse mode, and only a small fraction of the mass in an accumulation mode consistent with ash vaporization. Larger scale utility units firing residual oil were simulated using an 82 kW laboratory refractory-lined furnace. PM emissions from this unit were in good agreement with published data data including published emission factors. These data indicated that the refractory-lined combustor produced lower total but greater fine particulate emissions, as evident from a single unimodal PSD centered approximately around 0.1 micrometers diameter. These results have particular significance in considering the effects of fuel oil combustion equipment type on the characteristic attributes of the fine PM emitted into the atmosphere, and their ensuing health effects.

"Prepared for presentation at 5th International Conference on Technologies and Combustion for a Clean Environment, July 12-15, 1999, Lisbon, Portugal. Includes bibliographical references.