CONTINUOUSLY STIRRED DECANTING REACTOR - OPERABILITY AND STABILITY CONSIDERATIONS

A continuously stirred decanting reactor (CSDR) is a well-mixed vessel fed with two immiscible liquid phases, while its effluent consists of a single phase containing the reaction products. We consider a CSDR i n which a desired highly exothermic reaction occurs in one phase, whil e and undesirable exothermic side reaction occurs in the second extrac ting phase. The holdup of the two phases in the CSDR is sensitive to i ts temperature. Thus, the reactor has to be kept in a narrow temperatu re range to avoid breakthrough, that is, with effluent containing both phases, and to maintain a high selectivity of the desired product. Pi lot-plant data for a proprietary selective-oxidation process verified the predictions of the steady-state model. A high rate of heat generat ion may lead to various exotic and undesired periodic and aperiodic os cillations, which may shift the reactor out of the region of safe oper ation and have deleterious impact on the decantation efficiency. In so me cases, the oscillations lead to a breakthrough during part of the p eriod. To avoid these oscillatory states, one may have to maintain a s ufficiently small difference between the reactor and coolant temperatu res. We show how loci of local and global singular points of codimensi on 1 and 2 can be used to construct maps of parameters regions with qu alitatively different steady-state and dynamic bifurcation diagrams. T hese maps clearly describe the desirable regions of operation and poin t out all the potential stability and operability issues in other regi ons.