Ehsan Houshfar - Optimal mixtures to reduce the formation of corrosive compounds during straw combustion: a thermodynamic analysis

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      Publication Details (including relevant citation   information):

      Energy Fuels, 2011, 25 (7), pp 3223–3234

      DOI: 10.1021/ef2002475

      Publication Date (Web): June 1, 2011

      Copyright © 2011 American Chemical Society


      The thermodynamic analysis carried out focuses on biomass mixing   to reduce the formation of corrosive (mainly alkali) chlorides   during straw combustion. The calculations confirm the reduction   abilities of sewage sludge and peat and provide information on   the addition levels at which no corrosive compounds are expected   to form. The calculations provide insight into the mechanisms   responsible for the disappearance of alkali chlorides. The   mechanisms that can potentially take place are known (reaction   with sulfur and reaction with or adsorption on aluminosilicates   or other ash compounds). However, many aspects remain unclear,   and calculations cast light on several of them. The main result   obtained in this study is that, in a given binary mixture, the   chemical elements involved in the decomposition of corrosive   alkali chlorides (or preventing them from forming) change with   the mixing proportions, an important fact never mentioned to our   knowledge. The practical implications are significant: in a real   system, local elemental concentrations will vary; this means that   several mechanisms will simultaneously fight the formation of   corrosive alkali compounds. This new result may explain why the   experimental results from the literature are often confusing or   even contradictory even for a given mixture; the overall chemical   picture is not static. The chemical elements reacting with   alkalis during co-combustion of straw with sewage sludge or peat   are predicted to be S, Ca–S, and aluminosilicates.

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