APPLICATION OF THEORETICAL DIFFUSION MODELS IN PRESENCE OF A CATALYTIC REACTION

The fundamental problem in this work was to determine if methods of predicting mass transport rates in porous catalysts, developed from theory in the absence of chemical reaction, are valid in the presence of reaction. By using the ortho‐para shift of hydrogen over a ferric oxide gel catalyst as the reacting system, the effective diffusivity within the catalyst was determined from kinetic data on five different particle sizes of the catalyst. This effective diffusivity was then compared with that predicted by three different procedures recently published. These procedures predicted diffusivities approximately 40% below the experimentally obtained diffusivity. Although the differences between the experimental and predicted effective diffusivities can be regarded as within the limitations of the accuracy of the predictions, the observed differences may also be caused by some form of surface transport. Copyright © 1968 American Institute of Chemical Engineers