OPTIMUM OPERATION-REGENERATION CYCLES FOR FIXED-BED CATALYTIC CRACKING

A method is presented for computing the optimal operation-regeneration cycle for a fixed-bed reactor such that the yield of desirable product is maximized. Where the lengths of the operation and regeneration cycle are of similar magnitudes, the optimum cycle times become very critical. A kinetic-mathematical model of catalytic cracking conversion, which describes experimental results well, is the key to the optimization procedure. It characterizes the cracking behavior of catalysts in terms of a reaction velocity constant and a catalyst activity decay velocity constant. The effect of these important parameters on the optimum operation-regeneration cycle timing is discussed. An economic optimum space velocity exists which, when coupled with the optimum operation-regeneration cycle, gives an over-all optimum design. The method is aimed specifically at fixed-bed catalytic cracking, but is applicable to other fixed-bed processes describable by similar reaction kinetics. © 1968, American Chemical Society. All rights reserved.