caa a22 4500 463190866 CHVBK 20180406164908.0 cr unu---uuuuu 170326e20070701xx s 000 0 eng 10.1007/s10973-005-7494-x doi (NATIONALLICENCE)springer-10.1007/s10973-005-7494-x Influence of the atmosphere on the thermal decomposition kinetics of the CaCO3 content of PFBC coal flying ash [Elektronische Daten] [M. Gabal, D. Hoff, G. Kasper] The thermal decomposition behavior of hard coal fly ash (HCA2), obtained from the combustion of an Australian hard coal in thermoelectric power plants, in different atmospheres (air, N2 and N2-H2 mixture), was studied using thermogravimetry (TG), infrared-evolved gas analysis (IR-EGA), differential scanning calorimetry (DSC) and thermodilatometry (DIL) techniques. It was found that changing of the applied atmosphere affects the carbon content of the ash which results in different thermal decomposition behaviors. In air, the carbon content was oxidized to carbon dioxide before the decomposition of carbonate. In N2 or in N2-H2 atmospheres, the carbon content acts as a spacer causing a fewer points of contact between calcium carbonate particles, thus increasing the interface area which results in a decrease of the carbonate decomposition temperature. Following the carbonate decomposition, the iron oxide content of the ash undergoes a reductive decomposition reaction with the unburned carbon. This oxidation-reduction reaction was found to be fast and go to completion in presence of the N2-H2 mixture than in the pure nitrogen atmosphere due to the reducing effect of the hydrogen. The kinetics of the carbonate decomposition step, in air and N2-H2 mixture was performed under non-isothermal conditions using different integral methods of analysis. The dynamic TG curves obeyed the Avrami-Erofeev equation (A2) in air, and phase boundary controlled reaction equation (R2) in N2-H2 mixture. The change in the reaction mechanism and the difference in the calculated values of activation parameters with the change of the atmosphere were discussed in view of effect of the atmosphere on the carbon content of the ash. Springer Science+Business Media LLC, 2007 CaCO3 nationallicence coal fly ash nationallicence kinetics nationallicence thermal analysis nationallicence unburned carbon nationallicence Gabal M. Chemistry Department, Faculty of Science, Benha University, Benha, Egypt aut Hoff D. Institut für Mechanische Verfahrenstechnik und Mechanik, Universität Karlsruhe, Karlsruhe, Germany aut Kasper G. Institut für Mechanische Verfahrenstechnik und Mechanik, Universität Karlsruhe, Karlsruhe, Germany aut Journal of Thermal Analysis and Calorimetry Kluwer Academic Publishers-Plenum Publishers; http://www.springer-ny.com 89/1(2007-07-01), 109-116 1388-6150 89:1<109 2007 89 10973 https://doi.org/10.1007/s10973-005-7494-x text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10973-005-7494-x text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Gabal M. Chemistry Department, Faculty of Science, Benha University, Benha, Egypt aut NATIONALLICENCE 700 1- Hoff D. Institut für Mechanische Verfahrenstechnik und Mechanik, Universität Karlsruhe, Karlsruhe, Germany aut NATIONALLICENCE 700 1- Kasper G. Institut für Mechanische Verfahrenstechnik und Mechanik, Universität Karlsruhe, Karlsruhe, Germany aut NATIONALLICENCE 773 0- Journal of Thermal Analysis and Calorimetry Kluwer Academic Publishers-Plenum Publishers; http://www.springer-ny.com 89/1(2007-07-01), 109-116 1388-6150 89:1<109 2007 89 10973 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer