A recent paper developed a complex divided-wall column with two walls in a single vessel that was capable of separating a four-component mixture into four high-purity products. The walls created three internal sections in the middle of the column. One section was sealed at the bottom and had a small reboiler from which the lighter of the intermediate-boiling components was withdrawn. A second section was sealed at the top and had a small condenser and reflux drum from which the heavier of the intermediate components was withdrawn. The feed was introduced into the middle of the third section that was open at both ends. The top of this section was connected to the rectifying section of the vessel, which had a main condenser and reflux drum from which the lightest component was produced in the overhead distillate. This section was also open at the bottom and connected to the stripping section of the vessel, which had a main reboiler from which the heaviest component was produced as the bottoms. The purpose of this paper is to demonstrate that the process conceptual design and the practical plumbing is much more straightforward by using a conventional main column that has a side-stripper connected to the upper part of the column and a side-rectifier connected to the lower part of the column. Separating the functions into three vessels simplifies the design, has equivalent economics and improves the dynamic controllability. (C) 2020 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.