Optimal Distribution of Multifunctional Catalysts in a Packed Bed Reactor

The problem of the optimal distribution of two multifunctional catalysts is analyzed. Two methods for obtaining optimal catalyst profiles, an analytic—numeric method and the method of steepest ascent, are compared. Though the analytic—numeric method yields a more accurate solution, the method of steepest ascent is usually easier to apply. Optimal catalyst loading profiles are determined for two cases of commercial interest: selective oxidation of butene and naphtha reforming with bimetallic catalysts_ A sequential loading of the bismuth molybdate and the vanadium phosphate catalysts is recommended for low butene concentration levels, while at higher butene levels a mixed loading of the two catalysts may be desirable. For commonly encountered naphtha feedstocks a sequential loading of the Pt-Re and the Pt-Ir catalysts tends to be optimal. These compare well with experimental evidence in the literature.