Shrinking core like fluid solid reactions—A dispersion model accounting for fluid phase volume change and solid phase particle size distributions

A mathematical model is derived for the shrinking core like conversion of solids in a reacting fluid. As a technical example for this type of reaction the model is used to evaluate kinetic experiments on the production of carbide-derived carbon from silicon carbide. Therefore the simultaneous influence of reaction as well as diffusion is combined with the residence time behaviour of the reactor (tubular reactor), the non-constant gas phase volume over the extent of reaction and the particle size distribution of the solid substrate. The derived model is validated for accuracy against known solutions of boarder cases (e.g. shrinking core model of a single sphere, fluid phase volume change without dispersion or shrinking core and limitation by reactant feed).

Figure optionsDownload high-quality image (145 K)Download as PowerPoint slideHighlights
► Model for the conversion of silicon carbide to carbide-derived carbon.
► Simulation of a transient fluid/solid reaction with non constant fluid phase volume.
► Inclusion of particle size distribution for commercial powders.
► Combination of hyperbolic kinetics with a shrinking-core like mechanism.