ON INHIBITING RUNAWAY IN CATALYTIC REACTORS

We consider the problem of heat and mass transfer in porous catalyst pellets. Both the steady and time dependent operating characteristics are studied. Accurate approximate equations are derived from the basic governing equations of motion. A nonlinear stability analysis is employed to account for the observation that under certain conditions reactions on catalyst pellets can pass transiently stably into a region which would correspond to instability in the steady state. One consequence of our analysis is a possible control mechanism which inhibits temperature runaway by extending the stable operating characteristics desirable in modern reactors.