Pilot-Scale Study of the Effect of Selective Catalytic Reduction Catalyst on Mercury Speciation in Illinois and Powder River Basin Coal Combustion Flue Gases |
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| Authors: | Chun W Lee Ravi K Srivastava S Behrooz Ghorishi Jarek Karwowski Thomas W Hastings Joseph C Hirschi |
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| Institution: | 1. Office of Research and Development, National Risk Management Research Laboratory , U.S. Environmental Protection Agency , Research Triangle Park , NC , USA lee.chun-wai@epa.gov;3. Office of Research and Development, National Risk Management Research Laboratory , U.S. Environmental Protection Agency , Research Triangle Park , NC , USA;4. Babcock &5. Wilcox , Alliance , OH , USA;6. ARCADIS Geraghty &7. Miller, Inc. , Research Triangle Park , NC , USA;8. Cormetech, Inc , Durham , NC , USA;9. Illinois Clean Coal Institute , Carterville , IL , USA |
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| Abstract: | Abstract A study was conducted to investigate the effect of selective catalytic reduction (SCR) catalyst on mercury (Hg) speciation in bituminous and subbituminous coal combustion flue gases. Three different Illinois Basin bituminous coals (from high to low sulfur S] and chlorine Cl]) and one Powder River Basin (PRB) subbituminous coal with very low S and very low Cl were tested in a pilot-scale combustor equipped with an SCR reactor for controlling nitrogen oxides (NOx) emissions. The SCR catalyst induced high oxidation of elemental Hg (Hg0), decreasing the percentage of Hg0 at the outlet of the SCR to values <12% for the three Illinois coal tests. The PRB coal test indicated a low oxidation of Hg0 by the SCR catalyst, with the percentage of Hg0 decreasing from ～96% at the inlet of the reactor to ～80% at the outlet. The low Cl content of the PRB coal and corresponding low level of available flue gas Cl species were believed to be responsible for low SCR Hg oxidation for this coal type. The test results indicated a strong effect of coal type on the extent of Hg oxidation. |
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