170344 20260410165451.0 doi 10.1021/acs.energyfuels.6c00337 sideral 148844 ART-2026-148844 eng Jiménez, Santiago (orcid)0000-0001-9240-9644 Apparent Kinetics for Direct Oxidation of Iron Particles Determined from Tests at High Temperature in a Flat Flame Reactor 2026 The results from experiments with 63–75 μm iron particles burning in high temperature gases in a flat flame reactor with 4–16% O2 are presented and compared with calculations, with the main goal of determining the vicinity of the measured oxidation rates to the external diffusion limit. The simulations consider oxygen diffusion through the particle’s boundary layer and encompass internal processes (diffusion, liquid convection, reaction, etc.) in the form of apparent kinetics in the outer surface of the particle. The main magnitudes monitored experimentally are particle temperature and especially its oxidation degree, based on the mass of oxygen absorbed; both are determined at different heights along the reactor, which results in detailed profiles with distance traveled or residence time. The assumption of combustion in the (external) diffusion limit notably overestimates the oxidation rate and the peak temperature of the particles. On the contrary, the introduction of different, progressively slower apparent kinetics for each oxidation stage, with Fe–O ratios corresponding to Fe → FeO → Fe3O4 → Fe2O3, results in an excellent agreement to the experimental data, particularly regarding the oxidation curves. The same kinetics are shown to fit equally well previous results obtained in tests with 75–90 μm, recently published by the authors. Access copy available to the general public Unrestricted info:eu-repo/grantAgreement/ES/AEI/PID2022-141372OB-I00 info:eu-repo/semantics/openAccess by https://creativecommons.org/licenses/by/4.0/deed.es info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion Mayoral, M. Carmen Romeo, Luis M. Universidad de Zaragoza (orcid)0000-0001-7379-6159 5004 590 Universidad de Zaragoza Dpto. Ingeniería Mecánica Área Máquinas y Motores Térmi. 40, 13 (2026), 7171-7181 Energy fuels Energy and Fuels 0887-0624 3418308 http://zaguan.unizar.es/record/170344/files/texto_completo.pdf Versión publicada 3062539 http://zaguan.unizar.es/record/170344/files/texto_completo.jpg?subformat=icon icon Versión publicada oai:zaguan.unizar.es:170344 articulos driver 2026-04-10-13:46:57 ARTICLE