Optimal catalyst acitivity profiles in pellets—VIII. General nonisothermal reacting systems with arbitrary kinetics

Abstract

The theory of optimal catalyst activity profiles is extended to include the most general case, viz. the case of arbitrary number of reactions with arbitrary kinetics occurring in a nonisothermal catalyst pellet with finite external heat and mass transfer resistances. The catalyst performance index can be any one among effectiveness, selectivity or yield. Similar to previous results obtained for simpler situations, it is shown analytically that, in all cases, the optimal catalyst activity distribution is a Dirac delta function, i.e., for optimum performance, all the active catalyst should be deposited at a specific position within the pellet. This position depends, in general, not only on the physicochemical parameters involved but also on the choice of the catalyst performance index selected for optimization. The proof follows an approach which is different from what has been utilized previously, and is illustrated first for a simpler case, before proceeding to the general case.