CSTF and PFF in Series

If the final cell concentration (CX2 ) is known, the final substrate concentration (Cs ) can be calculated from Eq. (6.48). The residence time ofthe second fermenter can then be calculated using Eq. (6.49). If the residence time of the second fermenter is known, 

48) and (6.49) have to be solved simultaneously to estimate the cell and substrate concentrations. Another approach is to integrate Eq. (6.47) numerically until the given xp2 value is reached. 

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