The task of separating a multicomponent mixture into streams enriched in the respective constituents is commonly carried out in conventional distillation columns arranged in series. However, due to the scrutiny of tighter requirements for energy and cost efficiency, current research aims at alternative column arrangements that offer savings in both operational (energy) and capital costs. Among these are the Petlyuk or dividing wall column, in which three components are separated in a single shell using only one reboiler and one condenser. In this paper we extend the Petlyuk ideas to separations of four components, although extensions to more components is straightforward. We provide a general definition of Petlyuk arrangements and discuss alternative structures from the literature. Following this overview we consider the arrangements which allows for implementation in a single shell using dividing walls or vertical partitions.
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