STABILITY OF CHEMICAL REACTION IN FLUID CATALYTIC REACTORS

Abstract

Effect of the freeboard and the transition region on stability of fluid catalytic reactors is presented. Wall heat transfer coefficient and solid circulation rate have a significant effect on stability. These properties were measured. Both decrease as bed density decreases in the dilute phase (freeboard) and transition region. On the premise that non-catalytic violent reactions are induced due to temperature rise initiated by catalytic reactions in the dilute phase and/or the transition region, an approach to instability of the reaction system is presented by calculations. If the noncatalytic reactions are highly exothermic and their activation energies are large, the system can easily run away at any level of solid circulation. Thus, the possibility of these non-catalytic reactions, e. g. combustion or polymerization, should be avoided by such means as control of inlet compositions or close control of temperature in the dilute phase.