A review is provided about techniques that were used to evaluate the effective diffusivity of gases in catalyst/washcoat layers, as used in catalytic monoliths. The importance of making such measurements is described, to ensure that the choice of model for effective diffusivity can be verified, and if necessary an appropriate value of tortuosity can be back-calcd. Based on methods described in the literature, where possible expts. should be performed on actual monolith structures, rather than those that were reformed. The chromatog. technique is applied to a catalytic monolith and preliminary results of unpublished work are presented. A method of using a cut section from a catalytic monolith in a modified form of Wicke-Kallenbach diffusion cell' is also described. Examples from the patent literature are provided showing, how interest in layered catalyst systems has started to grow, illustrating how diffusion in porous layers can be exploited to develop designer catalyst systems.
|Number of pages||11|
|Publication status||Published - 2003|
- Combustion catalysts (monoliths
- review diffusivity catalyst coated monolith
- Pore (measurement of effective diffusivity in catalyst-coated monoliths)
- measurement of effective diffusivity in catalyst-coated monoliths)