Reactive Distillation Columns with Multiple Reactive Sections: A Case Study on the Disproportionation of Trichlorosilane to Silane

With reference to the disproportionation of trichlorosilane to silane, a three-stage consecutive reversible reaction with rather unfavorable reaction kinetics of a near zero thermodynamic conversion, an in-depth comparison in steady-state performance is performed between the reactive distillation column with a single reactive section (RDC-SRS) and those with multiple reactive sections (RDC-MRS), under the assumptions of the same total number of stages and the same total amount of catalyst employed. With the incremental arrangement of reactive sections, the RDC-MRS shows a steady improvement in steady-state performance with considerably reduced operating cost and capital investment as compared with the RDC-SRS. The great advantages originate essentially from the additional degrees of freedom resulting from the arrangement of multiple reactive sections in process synthesis and design. Apart from the coordination effect to the three-stage consecutive reversible reactions processed, the additional degrees of freedom serve also to reinforce internal mass integration and internal energy interaction between the reaction operations and the separation operations involved. Arrangement of side-condensers is also examined toward the RDC-MRS, and the outcomes reveal the thermodynamic rationale to adopt multiple reactive sections in process development. Although these findings are derived from the specific case study chosen, it should be considered to be of general significance for the synthesis and design of reactive distillation columns separating complicated reacting mixtures involving multiple reversible reactions.