Cellular automata approach to hybrid surface and diffusion controlled reactions

Cellular automata are frequently used to model chemical reactions and processes. In this paper, a direct relation is established between chemical kinetic models for surface and diffusion controlled reactions and cellular automata parameters. The considered particles are allowed to have growing/shrinking sizes, caused by the difference in the volume of the consumed reactant and the formed reaction product. From the moment a minimum diffusion layer thickness is obtained, the cellular automata approach can be applied to study the diffusion (ash layer) controlled model for both cases. In order to be able to also describe the reaction before this minimum diffusion layer thickness is formed, chemical reaction controlled and diffusion controlled models are combined here. Applying this hybrid model, a closed-form relation is found between the cellular automata parameters (particle size, reaction probability) and the fundamental kinetics of surface (β1) and diffusion (β2) controlled reactions.