The merits of catalyst pellets with non-uniform activity profiles are being increasingly noted. As for catalyst pellets with non-uniform catalytic activity profiles, the possibility of bringing the asymtotic behavior of the effectiveness factor identical for diverse pellet geometries and various activity profiles is studied. Such shape normalization is suggest for pellets with surface activity non-zero, and it is shown that when the surface activity is zero, a physically based shape normalization cannot be obtained. For a first order nonisothermal reaction in a catalyst pellet with catalytic-active ingredients deposited in the external shell, uniqueness and multiplicity criteria of steady states are derived with the asumption of pellet internal isothermality and gradient of concentration. This model of internal isothermality is justified by regular perturbation analysis and analytical improvement on predictions has resulted. In an isothermal reaction involving two species following two different schemes of bimolecular catalytic reaction mechanisms steady state uniqueness and multiplicity criteria are developed in a lumped parameter system. A reliable model of a monolithic converter utilizing three-way catalytsts is created, with diffusion-reaction within the catalytic layer, to obtain optimum reaction rate parameters and provide quantitative comparison with existing experimental results. (Jensen)
Problems involving diffusion and reaction in porous catalyst pellets and the modeling of catalytic converter for automotive exhaust system
Probleme der Diffusion und Reaktionen mit poroesen Katalysatoren in Form von Pellets und eine Modellvorstellung der katalytischen Umsetzung in Kraftfahrzeugauspuffsystemen
1980
134 Seiten
Hochschulschrift
Englisch
Catalytic Converter System Design for Automotive Exhaust
British Library Conference Proceedings | 1997
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