Modeling intra-particle convection in heterogeneous non-catalytic reacting systems

Abstract

A dynamic mechanistic model of a multi-phase heterogeneous batch reactor processing a non-catalytic uid-solid reaction is developed and numerically solved. The model takes into account both intra-particular convection and di usion phenomena, as well as chemical reaction between the uid and the solid. By addressing the until now ignored case of convection originated by the continuous increase of the particle porosity, this work enables a more realistic modeling of many non-catalytic uid-solid reaction systems. The dependency of the convective term on the chemical reaction rates gives rise to a space and time dependency of the intra-particle velocity thus increasing the mathematical complexity of the problem. The model is characterized by a set of PDEs coupled with adequate boundary conditions that are solved by the method of lines. An example of application of great importance to the chemical pulping of wood is used, emphasizing the di erences with the typical situation where only di usion is considered. ?