Batch, CSTR, and PFTR

Example 3-5 Compare the reactor volumes necessary to attain the conversions in the previous examples for first and second order irreversible reactions in a CSTR with a CSTR. 

The PFTR is the clear winner in this comparison if reactor volume is the only criterion. The choice is not that simple because of the costs of the reactors and pumping costs. 

We have now developed mass balance equations for the three simple reactors in which we can easily calculate conversion versus time tbatch residence time T, or position L for specified kinetics. For a first-order irreversible reaction with constant density we have solved the mass balance equations to yield 

Obviously, batch and PFTR will give the same conversion, but the CSTR gives a lower conversion for the same reaction time (batch) or residence time (continuous). 

We can immediately see major reactor design considerations between batch, CSTR, and PFTR. Table 3-1 shows the first of many situations where we are interested in the design of a reactor. We may be interested in choosing rninimum volume or many other process variables in designing the best reactor for a given process. 

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Comparisons of Possible Advantages (- -) and Disadvantages (—) of Batch, CSTR, and PFTR Reactors... 

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