EMISSIONS OF ORGANIC HAZARDOUS AIR-POLLUTANTS FROM THE COMBUSTION OF PULVERIZED COAL IN A SMALL-SCALE COMBUSTOR

The emissions of hazardous air pollutants (HAPs) from the combustion o f pulverized coal have become an important issue in light of the requi rements of Title III of the 1990 Clean Air Act Amendments, which impos e emission limits on 189 compounds and compound classes. Although prev ious field and laboratory studies have examined the emissions of some HAPs from coal combustion sources, no work has been done to evaluate t he emissions of a broad range of these compounds, particularly in the case of organics. Therefore, a study was conducted at the U.S. Environ mental Protection Agency's Air and Energy Engineering Research Laborat ory to characterize emissions of 76 organic HAPs in the flue gases fro m the combustion of pulverized coal in a small-scale down-fired combus tor. The combustor was operated under different conditions to simulate baseline, high excess air firing, and nitrogen oxide (NO(x)) controls by combustion modifications. Samples were extracted near the combusto r exit, upstream of any pollution control equipment. Data collected in dicate that relatively low levels of organic HAPs are present in the f lue gases for any of the combustion conditions; however, several compo unds were present that have not been reported in previous studies. To the extent these small-scale tests accurately simulate full-scale unit s, estimates based on these experiments indicate that the total HAP em issions from a large utility power plant are not likely to increase si gnificantly due to the installation of combustion modification techniq ues for NO(x) control.