A Reactive Distillation Column With Double Reacitve Sections For The Separations Of Two-Stage Consecutive Reversible Reactions

Reactive distillation integrates reaction operation with separation operation into an apparatus, the highly integration to two kinds of operations can lead to the reduction of energy cost as well as capital investment. Substantial economical profit have motivated its wide application in chemical industry, mainly including simple reversible reactions, parallel reversible reactions and two-stage consecutive reversible reactions. The two-stage consecutive reversible reactions can easily find its place in esterifications, acetalizations, trans-esterifications and aminations, but just a few literatures reported their studies in the separations of two-stage consecutive reversible reactions with reactive distillation columns. Their studies demonstrated the difficulty of achieving high conversion rate along with high selectivity, which results from the complicate coordination of two reaction operations involved.Up to now, the studies in reactive distillation column nearly all have been devoted to the conventional reactive distillation column with a single reactive section (RDC-SRS), which have difficult in achieving careful coordination of the reactions involved and then deteriorate the internal mass integration and internal energy integration between the reaction operations and the separation operation involved in the separations of two-stage consecutive reversible reactions. In order to make up the incapability of the RDC-SRS, a novel reactive distillation with double reactive sections (RDC-DRS) is proposed in which added degrees of freedom by the arrangement of two reactive sections not only allow careful coordination between two reaction operations involved and reinforcement of the internal mass integration and internal energy integration between the reaction operations and the separation operation involved. These features bring the strong competence of the RDC-DRS in utility cost and capital investment over the RDC-SRS.In the current work, a hypothetical two-stage consecutive reversible reaction and the two-stage consecutive trans-esterification of dimethyl carbonate with ethanol are used to evaluate the steady-state performance of the RDC-DRS. Under the two constraints that the total number of stages and reactive stages are kept the identical with the RDC-SRS, the reboiler duty is abated by6.39%and45.49%respectively.Considerable reduction of utility cost for the separations of the two-stage consecutive reversible reactions with the RDC-DRS not only indicate its potential competence in the kind of complicate reaction but also suggest that the number of reactive sections should be considered as an important variable in the synthesis and design of the reactive distillation column for the separations of the multiple complex reactions.