Effectiveness factor for thin catalytic coatings: Improved analytical approximation using perturbation techniques

The classical theory of diffusion and reaction inside catalytic pellets, based on the effectiveness factor concept, is applied to thin coatings supported on microchannels or nonporous pellets. We take advantage of this distinct geometrical characteristic to simplify the general problem. In particular, we show that the contribution from the geometry curvature can be written in terms of the effectiveness factor for a slab catalyst. An approximate method for the evaluation of η is proposed, which is accurate for linear and nonlinear kinetics, in uniform and nonuniform geometries. This presents a more convenient procedure for calculating η in structured reactors for process intensification.

► Perturbation solution for the effectiveness factor in a thin catalytic coating.
► Accurate description of linear and nonlinear isothermal kinetics.
► Improvement of the effectiveness factor calculation in nonuniform geometries.
► Effectiveness factor of an egg-shell catalyst with external mass transfer.