Dynamic Effectiveness Factor for Catalytic Particles with Anomalous Diffusion.

The effectiveness factor (EF) is a useful tool for the study of heterogeneous reaction systems, such as catalytic particles, where interactions of reaction-diffusion processes are involved. For simplicity, the study of EF is achieved on steady state operation (SSEF), but recent studies have suggested that EF can increase on dynamic operation conditions, especially when diffusive transport does not follow the Fick's law. In this paper, a study about the effect of anomalous diffusion on the dynamic effectiveness factor (DEF) in catalytic particles is presented. For this, it is considered a generalized Cattaneotype diffusion model described by differential equations of fractional order applied at rectangular, cylindrical and spherical geometries of the catalytic particles, which is analyzed in the frequency space by means the Fourier transform method. Numerical results, based on Bode and Nyquist diagrams, show the conditions and regions where the DEF values are largest than SSEF. [ABSTRACT FROM AUTHOR]