TECHNOLOGY-SPECIFIC MERCURY EMISSIONS FROM COAL COMBUSTION BY U.S. COUNTY OF COAL ORIGIN

Just as sulfur emissions from coal combustion vary with the amount of sulfur in coal, mercury emissions are correlated with the amount of mercury in coal. However, mercury emissions are also influenced by other factors such as coal chlorine, coal sulfur, boiler type, and emission control technology. Published equations that consider these factors are applied to coal-quality data to make technology-specific maps that show the geographic variation of predicted mercury emissions by U.S. county of coal origin. Results indicate that predicted mercury emissions do not vary with coal rank, but do vary with geologic age. Strategies to reduce mercury emissions include selection of low mercury coal for some power plants, selection of high chlorine coal for others, coal blending for some plants, and selection of low-sulfur coal where carbon in fly ash is used to reduce mercury emissions. Comparison of in-ground coal mercury content with produced coal mercury content suggest that coal washing might be most effective for coal from Ohio, and the northern tier of coal-producing counties in Pennsylvania.