Impact of Coal Chlorine on Mercury Speciation and Emission from a 100-MW Utility Boiler with Cold-Side Electrostatic Precipitators and Low-NOx Burners

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• 作者：Yan Cao ; Yufeng Duan ; Shawn Kellie ; Lingchuan Li ; Weibing Xu ; John T. Riley ; Wei-Ping Pan ; Paul Chu ; Arun K. Mehta ; and Ron Carty
• 刊名：Energy & Fuels
• 出版年：2005
• 出版时间：May 2005
• 年：2005
• 卷：19
• 期：3
• 页码：842 - 854
• 全文大小：524K
• 年卷期：v.19,no.3(May 2005)
• ISSN：1520-5029

文摘

Field tests on mercury speciation and emission while burning Kentucky and Illinois coals withdifferent chlorine contents were performed in a 100-MWe pulverized-coal boiler with low-NO_xburners. Seven coals were used during the tests and were grouped into two sets for comparison,with the baseline coal being shared between the two sets. The first set of four coals was used toinvestigate the effect of chlorine in coal on mercury emission and its speciation by selecting coalswith similar mercury contents and different chlorine contents. The four coals in the second setwere selected to investigate the effect of mercury contents in coal on mercury emission and itsspeciation by choosing coals with similar chlorine contents and different mercury contents. Themercury concentration and speciation in the flue gas were determined using the American Societyfor Testing and Materials (ASTM) standard Ontario Hydro Method (OHM) and a PS AnalyticalSemi-continuous Emissions Monitoring (SCEM) system. Flue gas samplings were performed attwo locations: upstream before the electrostatic precipitator (ESP) inlet and downstream afterthe ESP outlet. A thorough comparison between the two monitoring methods was made. Asampling bias was found in the OHM sampling performed at the ESP inlet, because of theaccumulation of ash with a high carbon content on the OHM filter. An ash-free sampling probeshould be used with the OHM impinger train for obtaining accurate mercury informationwhenever ash concentrations are high. Mercury emission and speciation for the seven test coalsat the ESP outlet location are described and discussed. Results indicate that the coal chlorinecontent has an impact on the mercury oxidation processes, which are mitigated by highconcentrations of SO₂. It is speculated that SO₂ limits Cl₂ formation.