A general approach for kinetic modeling of solid-gas reactions at reactor scale

National audienceSolid-gas reactions are of great interest in many industrial fields such as nuclear, chemistry, metallurgy, CO2 capture, etc. Industrial reactors where these reactions take place are difficult to understand. Indeed the solid phase is a granular medium through which circulate gaseous reactants and products. The properties of such a medium are modified in space and time due to chemical reactions occurring at the grains scale. The thermodynamic conditions are driven not only by the operating conditions but also by the heat and mass transfers in the reactor. Numerous models have been developed to account for the complexity of these transformations such as the grain model or the pore model , and all their improved derivatives. However most of these models are based on the law of additive reaction times of Sohn which is only valid in some special cases: if the order changes from the gas is equal to one, and for a shrinking core model. In all other cases, another approach is necessary to understand the kinetics of these reactions. In this goal, we have developed a multi-physic approach combining the resolution of the thermohydraulic equations with kinetic laws describing the heterogeneous reactions, for aggregated or separate particles