Product Distributions in PFRs and BRs

A quantitative treatment of the example discussed above is, as expected, the same for both a PFR and a BR, whereas the case of a CSTR will be tackled separately. 

In case both reactions are assumed to proceed irreversibly and to be of second order, the following molar balances can be written for the two first-mentioned types of reactors  

Here cb disappears, indicating that the ratio dcR/dcA does not depend on the concentration level of B. It is of interest to note that for consecutive reactions, A R S, an equation similar to Equation 3.266 is obtained. Therefore, the product distribution should become similar to the consecutive, irreversible reactions of first order. This can be verified by solving Equation 3.266. Consequently, we obtain the following equations for cr and dcR/dcA  

From Equation 3.271, the following expression for cr as a function of Ca is obtained  

This formula cannot be applied directly as such if ki happens to be equal to 2- For this special case, Equation 3.268 has the following solution  

---