Multiple CSTRs in Series with Different Temperatures

2 Multiple CSTRs in Series with Different Temperatures 

Another alternative is to operate the reactors at different temperatures. The sizing equations have to be modified to reflect that the specific reactions rates are different in the different reactors. For a 2-CSTR process, the quadratic equation given in Eq. (2.66) must be solved for reactor volume VR. The parameters k and k2 are the specific reaction rates at the two reactor temperatures Tri and Tr2, respectively. 

As a numerical example, suppose that we run the first reactor at 325 K and the second at 350 K. The resulting design has vessel volumes of 64.5 m3 with heat transfer areas of 74.8 m2. However, the percentage of the total AT driving force in the critical first reactor decreases only to 61%. This approach appears to be less effective than lowering both reactor temperatures. 

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