The stability conditions of the fed-batch reactor. Part I: Monod type growth kinetics

The semicontinuous operation of a biological reactor consists of batch operation periods interspaced by withdrawal of part of the contents and its renewal in the form of fresh feed. This system has certain advantages with regard to productivity in some cases and also to the control. A study has been made of this mode of operation for Monod kinetics under both ideal conditions (perfectly mixed reactor, instantaneous withdrawal and renewal) and real conditions. An assessment is given of the operating limits (cycle time, reintegrated volume) within which stable condition can be obtained. A determination is also undertaken of reactor performance in terms of productivity, utilisation of the substrate and final concentrations by comparison with the corresponding parameter values for the chemostat.