Double-partitioned dividing wall column for a multicomponent azeotropic system

Abstract

In this work, we propose the development of a dividing wall column (DWC) for the separation of ternary azeotropic mixture using an entrainer. Traditionally, this type of complex ternary system is traditionally separated in a triple column extractive distillation (TCED), among which, the first column is served as an extractive distillation. For this, at first, the first two towers are proposed to transform into a single column with a dividing wall. The resulting scheme is called here as extractive single-partitioned dividing wall column (ESPDWC). Subsequently, further intensification is made by merging all three columns of TCED into a single unit with two dividing walls, from which, one can get three products and the entrainer simultaneously with reasonably high purity. This proposed configuration is named as extractive double-partitioned dividing wall column (EDPDWC). To make the proposed extractive DWCs more practical, the heat transfer through the internal dividing wall is taken into account. For the separation of a ternary azeotropic mixture (tetrahydrofuran-methanol-water) with the use of an entrainer (ethylene glycol), the performance improvement of the proposed DWCs is quantified over the conventional TCED in terms of energy and cost savings. It appears that the proposed double-partitioned extractive DWC secures a better performance than its single-partitioned counterpart for the sample multiple binary azeotropes case.