title: Thermal decomposition kinetics of Brazilian limestones: effect of CO2 partial pressure.
abstract: The influence of the partial pressure of carbon dioxide (CO2) on the thermal decomposition process of a calcite (CI) and a dolomite (DP) is investigated in this paper using a thermogravimetric analyser. The tests were non-isothermal at five different heating rates in dynamic atmosphere of air with 0% and 15% carbon dioxide (CO2). In the atmosphere without CO2, the average activation energies (E(alpha)) were 197.4 kJ mol(-1) and 188.1 kJ mol(-1) for CI and DP, respectively. For the DP with 15% CO2, two decomposition steps were observed, indicating a change of mechanism. The values of E(alpha) for 15% CO2 were 378.7 kJ mol(-1) for the CI, and 299.8 kJ mol(-1) (first decomposition) and 453.4 kJ mol(-1) (second decomposition) for the DP, showing that the determination of E(alpha) for DP should in this case be considered separately in those two distinct regions. The results obtained in this study are relevant to understanding the behaviour changes in the thermal decomposition of limestones with CO2 partial pressure when applied to technologies, such as carbon capture and storage (CCS), in which carbon dioxide is present in high concentrations.
authors.affiliation: Group of Thermal and Fluids Engineering, School of Engineering of São Carlos, University of São Paulo, São Carlos, Brazil. iavila@sc.usp.br
authors.forename: Ivonete
authors.initials: I
authors.lastname: Avila
authors.forename: Paula M
authors.initials: PM
authors.lastname: Crnkovic
authors.forename: Fernando E
authors.initials: FE
authors.lastname: Milioli
authors.forename: Kai H
authors.initials: KH
authors.lastname: Luo
mesh_terms: D002119:Calcium Carbonate / Q000737:chemistry*; D002245:Carbon Dioxide / Q000737:chemistry*; D006358:Hot Temperature; D007700:Kinetics; D008274:Magnesium / Q000737:chemistry*; D013818:Thermogravimetry
chemical_list: D002245:Carbon Dioxide; D002119:Calcium Carbonate; D008274:Magnesium; C028042:calcium magnesium carbonate