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Show The baghouse/FGD system data in Figure 9 indicates that variation of the inlet mercury concentration over a range of 12 to 20 [ig/dscm had little impact on mercury emissions from the scrubber. For all three coals, emissions from the scrubber remained steady at approximately 1.4 |ig/dscm. FGD Mercury Emissions Control Summary Wet scrubber mercury removal efficiencies measured over a wide variety of operating conditions for several bituminous coals in the A E C D P pilot tests are consistent with that reported for commercial installations and other pilot operations9. The wet scrubber F G D system research completed to date has demonstrated that many factors impact the overall system mercury emissions control efficiency. The particulate emissions control upstream of the F G D system as well as the absorber tower design and operating conditions can have a significant influence on mercury emissions for a given coal. Although the distribution of mercury species at the scrubber inlet is a key variable influencing mercury control, it may not be the dominant factor in predicting overall mercury emissions control efficiency. Commercial and pilot data indicate that high-efficiency mercury emissions control can be achieved with a wet F G D system. The pilot data also indicate that F G D system design and operation impact mercury removal performance. Based on these results, a tray retrofit of an existing open tower scrubber m a y be a cost-effective means of enhancing both S 0 2 and mercury removal efficiency. Application of an average mercury emissions modification factor to predict mercury emissions based on measurements of mercury in the coal does not differentiate the measured influences of scrubber design and operation on emissions control. The Babcock & Wilcox Company, McDermott Technology, Inc. continues to evaluate various aspects of wet scrubber design, operation, and scrubber chemistry to develop techniques for enhancing mercury removal in F G D systems. Acknowledgments The Advanced Emissions Control Development Program is jointly funded by the U. S. Department of Energy's Federal Energy Technology Center, the Ohio Coal Development Office within the Ohio Department of Development, and Babcock & Wilcox - a McDermott company. The guidance and support of the project managers Thomas J. Feeley HI, of D O E - F E T C and Richard Chu of the Ohio Coal Development Office, are gratefully acknowledged. 15 |