(83a) Diffusion and Reaction in Catalytic Monolith Washcoat - Modeling Approaches

To model properly the effects of varying washcoat thickness, distribution of noble metals and other catalyst components on ignition phenomena and conversion a detailed description of processes inside the catalytic washcoat layer is necessary. In this contribution we first discuss the spatially 2D (1D+1D) model of entire monolith with effective internal diffusion. Then we describe detailed, spatially 3D model using digital reconstruction of a section of porous catalytic washcoat on a micro- and nano-scale. We briefly describe suitable numerical procedures for solution of such models and coupling of the models on different levels. We illustrate the methodology on examples of oxidation catalyst and NOx storage & reduction catalyst.

References:

P. Koci, F. Stepanek, M. Kubicek, M. Marek: Modelling of micro/nano-scale concentration and temperature gradients in porous supported catalysts, Chemical Engineering Science 62, (2007), 5380-5385. DOI:10.1016/j.ces.2006.12.033

M. Marek, Z. Grof, P. Koci, M. Kohout, J. Kosek, F. Stepanek: Multiscale modelling of transport, reaction and phase change in heterogeneous media, Journal of Chemical Engineering of Japan 40, (2007), 879-889. DOI:10.1252/jcej.07WE044

P. Koci, M. Kubicek, M. Marek: Modelling of TWC monolith converters with microkinetics and diffusion in the washcoat, Ind. Eng. Chem. Res. 43, (2004), 4503-4510. DOI:10.1021/ie034137k

A. Guethenke, D. Chatterjee, M. Weibel, B. Krutzsch, P. Koci, M. Marek, I. Nova and E. Tronconi: Current status of modeling lean exhaust gas aftertreatment catalysts, in "Advances in Chemical Engineering vol. 33: Automotive Emission Control", pp. 103-211, ed. G. B. Marin, ISBN: 978-0-12-373900-1, Elsevier 2007. DOI:10.1016/S0065-2377(07)33003-2

T. Stary, O. Solcova, P. Schneider and M. Marek: Effective diffusivities and pore-transport characteristics of washcoated ceramic monolith for automotive catalytic converter, Chemical Engineering Science 61, (2006), 5934-5943. DOI:10.1016/j.ces.2006.05.014

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