Dividing wall column—A breakthrough towards sustainable distilling

Dividing wall column (DWC) is a single shell, fully thermally coupled distillation column capable of separating mixtures of three or more components into high purity products. Compared to conventional columns-in-series and/or in-parallel configurations a DWC requires much less energy, capital and space. This makes DWC to something that corresponds with the present day idea of sustainable process technology. Based on published papers and patent literature this paper aims to give a complete overview of the work done so far on the research and implementation of DWCs, from early ideas on thermal coupling of distillation columns to practical issues that needed to be solved for their successful implementation. Approaches to short-cut and rigorous simulation, optimization, and control are highlighted, with particular focus on column internals and dimensioning, which is only conceptually considered in academic publications. A survey of relevant patents is included providing information on equipment innovations and application areas of industrial interest. Finally authors look at what is needed on research and engineering side to enable maximization of potential gains by building DWCs for obtaining four or even more products containing two or more partition walls in parallel, which is something not yet attempted in industrial practice.