Rates of Fluid-solid Catalytic Reactions

The assumptions inherent in this procedure should not be forgotten. They have been mentioned, but it is worthwhile to emphasize one, the con- stancy of C . This corresponds to an assumption that the maximum value of 9 is unity, or that the total number of active sites is constant. Also, note that we are considering a general approach to the formulation of rate equations for fluid-solid catalytic reactions. In several specific cases sufficient data have been obtained to permit a more detailed analysis of the mechanism and rates of the adsorption and surface-reaction steps. An example is the 

CHAPTER 9 KINETICS OF FLUID-SOLID CATALYTIC REACTIONS 

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As mentioned in Chap. 8, the rates of fluid-solid catalytic reactions are frequently reduced by poisoning. It is important to know how the reduction in rate varies with the extent of catalytic surface which has been poisoned. Experimental data show that the rate may drop linearly with the fraction of surface poisoned, or it may fall much more rapidly. The second form of behavior may be caused by selective adsorption of the poisoning substance on those catalysts sites which are active for the main reaction. Such adsorption on a relatively small part of the total catalyst would cause a large reduction in rate. An alternate explanation is possible if the main reaction is... 

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