Speciation and mass distribution of mercury in a bituminous coal-fired power plant

Lee, Sung Jun; Seo, Yong Chil; Jang, HeeJin; Park, Kyu Shik; Baek, Jeom-In; An, Hi Soo; Song, Kwang Chul

doi:10.1016/j.atmosenv.2005.12.013

Cited by 130 publications

(75 citation statements)

References 9 publications

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“…Hg R in precipitation, largely ionic Hg(II) (Mason et al, 1992), is emitted from natural and anthropogenic sources (Nacht et al, 2004;Lee et al, 2006) and produced by atmospheric oxidation of Hg 0 (Fogg and Fitzgerald, 1979), the rate of which varies spatially depending on the strength and abundance of atmospheric oxidants (Fitzgerald and Lamborg, 2003). Hg(II) is scavenged by particles (Lamborg et al, 2000), and as noted, levels of Hg R in precipitation are highly dependent on the concentration and nature of particulate material.…”

Section: Potential Sources Of Mmhgmentioning

confidence: 99%

Aqueous phase methylation as a potential source of methylmercury in wet deposition

Hammerschmidt

Lamborg

Fitzgerald

2007

Atmospheric Environment

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Section: Potential Sources Of Mmhgmentioning

confidence: 99%

Aqueous phase methylation as a potential source of methylmercury in wet deposition

Hammerschmidt

Lamborg

Fitzgerald

2007

Atmospheric Environment

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“…According to 30 previous on-site measurements in coalfired power plants and industrial boilers (Kellie et al, 2004;Duan et al, 2005;Lee et al, 2006;Zhou et al, 2006;Chen et al, 2007;Yang et al, 2007;Chen et al, 2008;Wang et al, 2008;Zhou et al, 2008;Kim et al, 2010b;Wang et al, 2010a;Zhang et al, 2012a;L. Zhang et al, 2013a), mercury speciation after the boiler and before APCDs is mainly determined by coal properties, specifically chlorine, mercury, and ash contents in coal.…”

Section: Zhang Et Al: Mercury Transformation and Speciation In Flmentioning

confidence: 99%

“…The charging anode of ESP can neutralize Hg 2+ and convert it to Hg 0 , while Hg 0 in flue gas continues to be oxidized to Hg 2+ via heterogeneous reactions in ESP under temperatures of 150-200 • C. Therefore, Hg 0 concentration can either increase or decrease inside ESP depending on the processes interplay. On-site measurements showed an average mercury removal efficiency of 29 % for ESP with a large range of 1-74 % (Goodarzi, 2004;Guo et al, 2004;Kellie et al, 2004;Tang, 2004;Duan et al, 2005;Lee et al, 2006;Chen et al, 2007;Yang et al, 2007;Wang et al, 2008;Zhou et al, 2008;Kim et al, 2010b;Shah et al, 2010;ICR, 2010;Wang et al, 2010a;Zhang et al, 2012a). Nevertheless, ESP installed after a CFB boiler can achieve an average of 74 % mercury removal due to the high Hg p proportion in flue gas (Chen et al, 2007;ICR, 2010;Zhang, 2012).…”

Section: Mercury Transformation In Electrostatic Precipitator (Esp)mentioning

confidence: 99%

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Mercury transformation and speciation in flue gases from anthropogenic emission sources: a critical review

et al. 2016

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Abstract. Mercury transformation mechanisms and speciation profiles are reviewed for mercury formed in and released from flue gases of coal-fired boilers, non-ferrous metal smelters, cement plants, iron and steel plants, waste incinerators, biomass burning and so on. Mercury in coal, ores, and other raw materials is released to flue gases in the form of Hg 0 during combustion or smelting in boilers, kilns or furnaces. Decreasing temperature from over 800 • C to below 300 • C in flue gases leaving boilers, kilns or furnaces promotes homogeneous and heterogeneous oxidation of Hg 0 to gaseous divalent mercury (Hg 2+ ), with a portion of Hg 2+ adsorbed onto fly ash to form particulate-bound mercury (Hg p ). Halogen is the primary oxidizer for Hg 0 in flue gases, and active components (e.g., TiO 2 , Fe 2 O 3 , etc.) on fly ash promote heterogeneous oxidation and adsorption processes. In addition to mercury removal, mercury transformation also occurs when passing through air pollution control devices (APCDs), affecting the mercury speciation in flue gases. In coal-fired power plants, selective catalytic reduction (SCR) system promotes mercury oxidation by 34-85 %, electrostatic precipitator (ESP) and fabric filter (FF) remove over 99 % of Hg p , and wet flue gas desulfurization system (WFGD) captures 60-95 % of Hg 2+ . In non-ferrous metal smelters, most Hg 0 is converted to Hg 2+ and removed in acid plants (APs). For cement clinker production, mercury cycling and operational conditions promote heterogeneous mercury oxidation and adsorption. The mercury speciation profiles in flue gases emitted to the atmosphere are determined by transformation mechanisms and mercury removal efficiencies by various APCDs. For all the sectors reviewed in this study, Hg p accounts for less than 5 % in flue gases. In China, mercury emission has a higher Hg 0 fraction (66-82 % of total mercury) in flue gases from coal combustion, in contrast to a greater Hg 2+ fraction (29-90 %) from non-ferrous metal smelting, cement and iron and/or steel production. The higher Hg 2+ fractions shown here than previous estimates may imply stronger local environmental impacts than previously thought, caused by mercury emissions in East Asia. Future research should focus on determining mercury speciation in flue gases from iron and steel plants, waste incineration and biomass burning, and on elucidating the mechanisms of mercury oxidation and adsorption in flue gases.

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“…Major mercury sources from human activities are coal-fired electric utility boilers, where speciation depends on the operating conditions, including the type of coal used and flue gas temperature and composition. Mercury compounds from combustion sources consist mainly of gaseous elemental mercury (Hg 0 ), gaseous oxidized mercury (Hg 2+ ), and particle-bound mercury (Hg p ) [1]. Theoretical first-principle approaches have been used to study mercury speciation, including kinetic modeling [2] and thermodynamic equilibrium calculations [3].…”

Section: Introductionmentioning

confidence: 99%

Predictive modeling of mercury speciation in combustion flue gases using GMDH-based abductive networks

Abdel-Aal

2007

Fuel Processing Technology

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Abstract:Modeling mercury speciation is an important requirement for estimating harmful emissions from coal-fired power plants and developing strategies to reduce them. First principle models based on chemical, kinetic, and thermodynamic aspects exist, but these are complex and difficult to develop. The use of modern data-based machine learning techniques has been recently introduced, including neural networks. Here we propose an alternative approach using abductive networks based on the group method of data handling (GMDH) algorithm, with the advantages of simplified and more automated model synthesis, automatic selection of significant inputs, and more transparent input-output model relationships. Models were developed for predicting three types of mercury speciation (elemental, oxidized, and particulate) using a small data set containing six inputs parameters on the composition of the coal used and boiler operating conditions. Prediction performance compares favourably with neural network models developed using the same dataset, with correlation coefficients as high as 0.97 for training data. Network committees (ensembles) are proposed as a means of improving prediction accuracy, and suggestions are made for future work to further improve performance.

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Speciation and mass distribution of mercury in a bituminous coal-fired power plant

Cited by 130 publications

References 9 publications

Aqueous phase methylation as a potential source of methylmercury in wet deposition

Aqueous phase methylation as a potential source of methylmercury in wet deposition

Mercury transformation and speciation in flue gases from anthropogenic emission sources: a critical review

Predictive modeling of mercury speciation in combustion flue gases using GMDH-based abductive networks

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