Abstract
A numerical solution is examined for calculation of the effectiveness factors for porous catalyst particles in the case of isothermal first-order reactions at steady state, as analytical solutions become complicated for irregular shapes.
The correctness of the model and of the numerical solution is demonstrated by comparing the results obtained for cylindrical extrudates with the analytical solutions derived from diffusion limitation theory.
The numerical solution was applied to the calculation of the effectiveness factors for extruded catalysts with various kinds of cross-sections, i.e. circle, capital letter L, dumbbell, trilobe and quadrulobe. Calculations show that non-cylindrical extrudates have effectiveness factors equivalent to those of cylindrical extrudates if the characteristic particle size is expressed as a ratio of particle volume to external surface area. Thus numerical analysis makes it possible to estimate the effect of diffusion limitation on the activity of any shaped catalyst.
