Global kinetic modelling of the reaction of soot with O2 and NOx on Fe2O3 catalyst

This study deals with the catalytic reaction of NOx and soot on Fe2O3 to yield N-2 and CO2 in excess of oxygen. Based on the three types of kinetic experiments, i.e. temperature programmed oxidation (TPO), transient examinations and gradient-free loop reactor experiments, as well as mechanistic studies presented recently a global kinetic model is established. The model includes catalytic effect of the iron oxide on soot/O-2 reaction, whereas it is assumed that NOx reduction occurs on the soot without direct participation of Fe2O3. Furthermore, the model implies global kinetic expressions for the COx formation and NOx reduction. These equations include the evolution of the surface area of soot and the correlation of reactive carbon sites (C-f) with those specifically involved in NO, reduction (C*). The kinetic model is sequentially developed by accounting for the catalytic and non-catalytic soot/O-2 as well as soot/NOx/O-2 conversion. Kinetic parameters are taken from the literature and are also determined from a fit to experimental data. Comparison of measured and calculated data shows accurate reproduction of the experiments and the model. Finally, the kinetic model is validated by some simulations. (C) 2008 Elsevier B.V. All rights reserved.