Interprétation cinétique des mesures d'ignition dans le cas des systèmes réactionnels gaz-solide

A quantitative interpretation of the ignition phenomenon is proposed which allows the determination of the kinetic parameters of exothermic chemical reactions of the type: gas + solid → gas. Two kinetic methods are presented for the case of unsteady state reaction and their application in practice is discussed. The first method is characterized by a gas-solid heat transfer coefficient different in each experiment, the second one by a constant heat transfer coefficient. The reaction kinetics are determined from the experimental conditions at ignition. Both methods are then applied successfully to a reacting system of complex geometry, hydrodynamics and kinetic mechanism: the catalysed oxidation of carbon black, measured by thermogravimetry.