By John B. Butt
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Extra resources for Activation, Deactivation, and Poisoning of Catalysts
The rate of the main reaction is, in general, for a system of constant activity rate of reaction =f(c1,c2, c 3 , . . , c,·, T) =f(c„ T) (2-1) When we consider deactivating systems, Eq. (2-1) represents the initial reaction rate, that is, [ reaction rate of catalyst initially. lo=A(ci9T) (2-2) If, now, after some deactivation of the catalyst has occurred, the rate of the main reaction is measured again at the same values of the concentrations and temperature to obtain ^"reaction rate ofl catalyst after = Mt=f2(ci9T) L deactivation J (2-3) it is convenient then to define the activity as a^mt/m0 (2-4) Thus the activity is an operational parameter of considerable utility in characterizing the changes in the reaction rate of a catalyst as it deactivates, and it is obtained easily and directly from the experimental results.
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24 gave the parameter values for Eq. (2-48) listed in Table 2-1. The small range of E indicates that the rate-determining step is not affected by poisoning. However, K does not change proportionately with 40 2. 4 activity, as postulated in the separable formulation, and q decreases by almost 40% over the activity range investigated. Figure 2-1 shows a com parison of the fit of data by Eq. 06/c), respectively. Clearly there are significant deviations from the model of kinetic separability. 30 "250 (Ι/ΌχΙΟ3, K_l Fig.