THERMAL REGIMES IN COCURRENTLY COOLED FIXED-BED REACTORS

Seven different thermal regimes can be achieved when an exothermic fir st-order reaction takes place in a cocurrently cooled fixed-bed reacto r. All the regimes are feasible in reactors where the inlet temperatur e of the coolant is different from that of the reacting stream. New th ermal regimes were found; they are qualitatively very different from t hose commonly reported in the literature (e.g. maximum-minimum, or min imum-maximum profiles, cold-spot regime). Based on a pseudohomogeneous plug-flow model, the conditions of existence for all the regimes, as well as guidelines to select the operating conditions to achieve the d esired profile properly are presented. The diversity of feasible regim es can be very useful to track optimum thermal profiles required to so lve practical optimization problems.