PSEUDOADIABATIC OPERATION FOR FIXED-BED CATALYTIC REACTORS - METHODS FOR FINDING THE LIMITS OF THE REGIME

Fixed bed reactors for exothermic catalytic reaction offer special cha llenges given the problems of safe operation and hot spot development. These problems can be considered in the context of so-called pseudoad iabatic operation (PO), with the highest temperature occurring at the reactor exit. This study deals with the derivation of analytical equat ions for finding the limiting PO and POAT (pseudoadiabatic operation f or the average cross-sectional temperature) conditions. These relation ships are used to validate a numerical methodology for the search of t hese limiting conditions in the case of complex kinetic models. It is observed that, in addition to the hot spot (HS) operation and PO, ther e are other possible regimes: decreasing temperature profile (DTP), is othermal (IS) operation, cold spot (CS) operation, hot spot-cold spot (HS-CS) and cold spot-hot spot (CS-HS) operations. Identification of t hese regimes for a given kinetic model is of importance in exploring t he conditions leading to PO and POAT regimes.