Systematic Synthesis of Dividing-wall Columns for Multicomponent Distillations

Abstract Dividing-wall columns(DWC) are intensified distillation systems for multicomponent separations. They have the potential to save both energy and capital costs significantly than conventional simple column configurations. The several DWC columns for ternary distillations have been figured out by some creative activities from different inventors. Recently they have gained the momentum to be widely implemented in industrial separation processes. As industrial separation problems very often involve four or more components, for such problems, due to complexity, it is impossible to find all the feasible DWC columns by inventive activities. On the other hand, industrial experience shows that the optimal system for a specific application can only be guaranteed by predefining all of the feasible options. In this work, a procedure for systematic synthesis of DWC columns for multicomponent distillation is presented. Starting from the conventional simple column configurations for the separation of a multicomponent mixture, a four-step procedure is formulated which systematically generates all the possible DWC columns. First, the subspace of the possible thermally coupled configurations corresponding to the simple column configurations is generated. Then, the subspace of the possible thermodynamically equivalent structures corresponding to the thermally coupled configurations is produced. Finally, the subspace of the DWC columns corresponding to the thermodynamically equivalent structures is achieved. The method is simple, easy-to-use and can systematically synthesize all the possible DWC columns. An example of quaternary distillation is used to illustrate the synthesis procedure which is applicable to a mixture with any number of components.