Multiple Reactive Sections: An Effective Option for the Design of Reactive Distillation Columns

In this paper, a novel reactive distillation column with multiple reactive sections (RDC-MRS) is proposed for the separations of reacting mixtures with complicated thermodynamic properties and reaction kinetics. The typical examples include those with multiple-stage consecutive reactions and/or unfavorable relative volatilities.^1-4 The arrangement of multiple reactive sections not only allows the careful coordination of the multiple reaction operations involved, but also provides additional degrees of freedom for the reinforcement of internal mass integration and/or internal energy integration between the reaction operations and the separation operation involved, which could facilitate the RDC-MRS to be more advantageous than the conventional reactive distillation column with a single reactive section (RDC-SRS) in operating cost and capital investment. A number of representative example systems, including the separations of reacting mixtures with multiple-stage consecutive reactions and/or unfavorable relative volatilities, are chosen to evaluate the steady-state performance of the RDC-DRS. With the constraints of the same total number of stages and the same total amount of catalyst, the RDC-MRS is clearly demonstrated to require less utility consumption and capital investment than the RDC-SRS and this outcome indicates that the former could be a competitive alternative to the latter in the separations of the reacting mixtures with complicated thermodynamic properties and reaction kinetics. The number of reactive sections should therefore be viewed as an important decision variable for the synthesis and design of reactive distillation columns.