| Abstract: | The classical fixed bed C3–C4 paraffin dehydrogenation process is a cyclic operation in which the reactor alternates between reaction and reheat cycles. During the reheat cycle, the necessary energy for the dehydrogenation reaction is stored in the fixed bed by passing hot air through it. In this established technology, both the hydrocarbon reactant and the reheat hot air are fed into the fixed bed from the same end (top) of the reactor. This is termed parallel flow (cocurrent) operation. An alternative feeding fixed bed has the hydrocarbon reactant and the reheat air entering from the opposite ends of the reactor. This is termed reverse flow (countercurrent) operation. This alternate creates an ideal temperature profile for an equilibrium limited endothermic reaction (rising temperature profile along the reactor). The transient flow behavior of both parallel and reverse flow reactors has been modelled and the dynamics of temperature profile development for both concepts have been analyzed. Based upon the model predictions, the characteristics as well as the reactor stability of the both concepts have been discussed. |
