Characterization of Sulfate Emissions from Nonutility Boilers Firing Low-S Residual Oils in New York City

Abstract

A 10 day study was carried out in the New York Metropolitan area to characterize the sulfur oxides (SO _x ) emissions from four packaged boilers burning a 0.3% S hydrodesulfurized residual oil. Emission rates were calculated for SO₂, total sulfate, and particulate matter expressed as g emitted/gal of oil fired. Sulfate emissions amounted to ≃ 13.4% of the SO _x from the sources. The sulfate emission factor was found to be related to the accumulation of V-containing ash in the boilers resulting in the catalytic oxidation of SO₂. Nearly 35,000 boilers of these types are operational in New York City, especially in the winter, to provide heat and hot water. Their elevated suifate emission rates could play a dominant role Jn the occurence of elevated sulfate levels near the metropolitan area during winter episodes.