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Show A*.-I MERCURY EMISSIONS CONTROL STRATEGIES FOR COAL-FIRED POWER PLANTS Michael J. Holmes Ralph T. Bailey George A. Farthing Debi A. Madden Babcock & Wilcox Company, McDermott Technology, Inc. 1562 Beeson Street Alliance, Ohio 44601 Abstract In cooperation with the U.S. Department of Energy, the Ohio Department of Development's Ohio Coal Development Office, and Babcock & Wilcox, McDermott Technology, Inc. has evaluated the formation and control of trace element emissions from the combustion of Ohio bituminous coals. In response to industry concern over potential regulation of mercury emissions from utility boilers, testing in Phases EI and HI of the Advanced Emissions Control Development Program was focused on measurement of the quantity and species distribution of mercury downstream of the boiler and emissions control equipment. Testing included evaluation of the potential for controlling mercury emissions in coal-fired utility power plants using conventional particulate control and flue gas desulfurization (FGD) equipment. This paper presents the results of mercury emissions testing on pilot-scale facilities at the Alliance Research Center. The emissions control techniques discussed in this paper include wet limestone SO2 scrubbing, sorbent injection systems, a baghouse, and an electrostatic precipitator (ESP). Introduction Under the Clean Air Act Amendments of 1990, the United States Environmental Protection Agency (US E P A ) was mandated to evaluate emissions of hazardous air pollutants (HAPs) from fossil fuel-fired electric generating units and to provide a summary report to Congress on mercury emissions sources, controls, and health impacts. Figure 1 identifies the trace elements of primary concern. Field measurements sponsored by the United States Department of Energy (US D O E ) and the Electric Power Research Institute (EPRI) have characterized H A P emissions from a variety of coals, boiler types, and emissions control equipment configurations. The results have indicated that existing particulate emissions control equipment - electrostatic precipitators (ESPs) and baghouses - provide high efficiency removal of most of the trace elements generated by coal combustion. However, for mercury, the data revealed that a wide range of removal efficiencies exist for commercial particulate and S 0 2 emissions control equipment. The Babcock & Wilcox Company, McDermott Technology, Inc. is conducting testing to evaluate causes of the observed performance variations and optimize the use of 1 |