| OCR Text |
Show conventional systems to provide near-term solutions for enhanced control of mercury emissions from coal-fired boilers. Figure 1. Trace Elements of Primary Concern. The U S EPA, state environmental agencies, and regional associations continue to evaluate the need for regulation of mercury emissions from coal-fired boilers to reduce human exposure to this persistent, bio-accumulative trace element. Mercury is emitted from coal-fired boilers in very low concentrations. Based on field sampling at utility sites, uncontrolled mercury emissions from coal combustion are generally in the range of 5 to 30 jug/dscm, already well below the regulated emissions limit of 80 |ig/dscm for municipal solid waste ( M S W ) boilers. Annual mercury emissions from a coal-fired unit not equipped with SO2 emission controls are on the order of one-third to one pound of mercury per M W of generating capacity1. However, as a group, coal-fired boilers represent a major unregulated source of mercury emissions to the environment. The U S E P A and EPRI estimate that coal-fired utility boilers emit 50 to 55 tons of mercury per year in the U.S2. The variation associated with the reported mercury emissions control efficiency of commercial emissions control systems and the potential for mercury regulations, suggest that additional research is required. It is necessary to better define causes for the observed performance variations and maximize mercury emissions control performance of conventional flue gas emissions control systems. In cooperation with the U S D O E and the Ohio Coal Development Office ( O C D O ) within the Ohio Department of Development, Babcock & Wilcox ( B & W ) is evaluating mercury emissions control performance of commercial F G D systems as well as advanced systems under development by B & W . The Advanced Emissions Control Development Program (AECDP) is directed toward demonstration of practical, cost-effective strategies for reducing H A P emissions from coal-fired boilers using conventional particulate and S 0 2 control equipment. 2 |
