TRANSIENT KINETICS FROM THE TAP REACTOR SYSTEM - APPLICATION TO THE OXIDATION OF PROPYLENE TO ACROLEIN

Transient kinetic data have been extracted by use of the Temporal Anal ysis of Products (TAP) reactor system. In the TAP reactor high resolut ion transient pulse experiments are performed under vacuum conditions. A rigorous model is developed and applied to the determination of Knu dsen diffusivities from experiments with inert pulses. The model was a pplied to the catalytic oxidation of propylene over an industrial mult icomponent bismuth molybdate catalyst. By fitting simulated curves to the experimentally observed response curves, kinetic parameters for th e different elementary steps of the reaction were determined. It was s hown that the adsorption of propylene is practically irreversible at r eaction temperature and that CO2 and acrylic acid are formed in consec utive reactions from propylene via acrolein. From the values for the k inetic parameters it is proven that under industrial conditions the ad sorption of propylene is rate determining. The surface coverage under typical conditions is shown to be quite low. The kinetic model is succ essfully used for the simulation of a steady state reactor operating u nder industrial conditions. (C) 1995 Academic Press, Inc.