Nonideal Reactors Some Examples

FIG. 19-6 Some examples of nonideal flow in reactors. (Fig. Ill in Levenspiel, Chemical Reaction Engineering, John Wiley ir Sons, 1999.)... 

The flows in PFR and MFR can be precisely deflned by simple mathematical eqnations, and the batch reactor is simply the batch version of the PFR. A reactor is now considered where the flow is between plug and fnlly mixed, i.e., a nonideal reactor. Two common examples of such partially mixed reactors are the recycle reactor and the tanks-in-series reactor. In the recycle reactor, part of the outlet from a reactor is recycled at the inlet, thns establishing some mixing between the downstream and the upstream fluids. In the tanks-in-series reactor, several mixed-flow reactors are operated in series. A single MFR is fully mixed, whereas an inflnite nnmber of MFRs (or a... 

The problem of nonideal flow is directly related to scale-up. For example, there is no reason to pilot-plant if the reactor operates in an ideal mode. However, the magnitude or degree of (he nonideality of flow can significantly impact design and performance equations. This effect should not be ignored by the practicing engineer in some applications it is discussed in mote detail in a later section. 

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