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The role of unburned carbon concentrates from fly ashes in the oxidation and retention of mercury / P. Abad-Valle in Chemical engineering journal, Vol. 174 N° 1 (Octobre 2011) 

Public ISBD [article]  in Chemical engineering journal > Vol. 174 N° 1 (Octobre 2011) . - pp.86-92 Titre : The role of unburned carbon concentrates from fly ashes in the oxidation and retention of mercury Type de document : texte imprimé Auteurs : P. Abad-Valle, Auteur ; M.A. Lopez-Anton, Auteur ; M. Diaz-Somoano, Auteur Année de publication : 2012 Article en page(s) : pp.86-92 Note générale : Génie chimique Langues : Anglais (eng) Mots-clés : Mercury  Fly  ash  Retention  Oxidation Résumé : During the combustion of coal in power plants Hg is released from the coal into the environment. Several technologies are under developed to reduce these emissions, but the need to implement new control systems will depend in part on the extent to which Hg can be captured in the flyash. Previous studies have demonstrated that flyashes may not only retain Hg species but also oxidize Hg0(g). This should be taken into consideration when developing technologies for Hg retention. The aim of this study is to acquire a better understanding of the interactions between Hg0(g) and flyashes and to clarify the effect of unburnedcarbon and the flue gas composition upon the retention and oxidation mechanisms. A series of retention, oxidation and desorption experiments were carried out using lab-scale reactors. All the results obtained indicate that the interaction between Hg and flyash is mainly chemical since the retention of Hg involves oxidation. Moreover, if the oxidation takes place in gas phase, condensation of oxidized mercury occurs. Carbonaceous matter is involved in most of the retention and oxidation mechanisms between Hg and flyash. The carbonconcentrates with the highest Hg retention capacity produce the highest Hg oxidation. The gas mixtures containing O2 + CO2 + SO2 + H2O were observed to increase Hg retention in the carbonconcentrates from flyashes. However, the presence of HCl in the mixtures may increase or decrease Hg capture. Heterogeneous oxidation was only significant in the flyash fractions enriched in unburnedcarbon. ISSN : 1385-8947 En ligne : http://www.sciencedirect.com/science/article/pii/S1385894711010114 [article] The role of unburned carbon concentrates from fly ashes in the oxidation and retention of mercury [texte imprimé] / P. Abad-Valle, Auteur ; M.A. Lopez-Anton, Auteur ; M. Diaz-Somoano, Auteur . - 2012 . - pp.86-92. Génie chimique Langues : Anglais (eng) in Chemical engineering journal > Vol. 174 N° 1 (Octobre 2011) . - pp.86-92 Mots-clés : Mercury  Fly  ash  Retention  Oxidation Résumé : During the combustion of coal in power plants Hg is released from the coal into the environment. Several technologies are under developed to reduce these emissions, but the need to implement new control systems will depend in part on the extent to which Hg can be captured in the flyash. Previous studies have demonstrated that flyashes may not only retain Hg species but also oxidize Hg0(g). This should be taken into consideration when developing technologies for Hg retention. The aim of this study is to acquire a better understanding of the interactions between Hg0(g) and flyashes and to clarify the effect of unburnedcarbon and the flue gas composition upon the retention and oxidation mechanisms. A series of retention, oxidation and desorption experiments were carried out using lab-scale reactors. All the results obtained indicate that the interaction between Hg and flyash is mainly chemical since the retention of Hg involves oxidation. Moreover, if the oxidation takes place in gas phase, condensation of oxidized mercury occurs. Carbonaceous matter is involved in most of the retention and oxidation mechanisms between Hg and flyash. The carbonconcentrates with the highest Hg retention capacity produce the highest Hg oxidation. The gas mixtures containing O2 + CO2 + SO2 + H2O were observed to increase Hg retention in the carbonconcentrates from flyashes. However, the presence of HCl in the mixtures may increase or decrease Hg capture. Heterogeneous oxidation was only significant in the flyash fractions enriched in unburnedcarbon. ISSN : 1385-8947 En ligne : http://www.sciencedirect.com/science/article/pii/S1385894711010114