DESIGN CONSIDERATIONS FOR TUBULAR REACTORS WITH HIGHLY EXOTHERMIC REACTIONS

Practical guidelines are required for the design and operation of complicated catalytic packed-bed reactors. Primary among design considerations is the avoidance of operating regions of high parametric sensitivity, in which small changes in operating conditions can lead to thermal runaway in the reactor. Existing criteria for predicting these regions rely on complex mathematical formulations for differential sensitivity between input and output variables. The present work centers on the development of practical design criteria for avoiding reactor instability and temperature sensitivity in multitubular packed-bed reactors. A set of simple guidelines is proposed for the sizing of reactors and proper selection of operating conditions. The implications of these open-loop sensitivities for a controlled reactor are investigated. It is shown through simulation studies that violation of the proposed criteria leads to control problems and difficulty in operating at the design point.