Introduction to Dividing Wall Columns : CEP

Published in AIChE’s Chemical Engineering Progress (March 2019), this DWC Innovations article is a practical introduction to dividing wall columns (DWCs) — distillation columns that add an internal wall to separate a mixture into three or more high-purity products within a single shell, using 20–30% less capital, energy, and plant space than a conventional sequence of columns. It explains how a DWC works as a thermally and mechanically integrated Petlyuk column that curbs the component remixing which penalizes ordinary side-cut columns, and walks through the three basic wall configurations — middle, top and bottom — and where each fits best. A worked example follows an Indian refinery upgrading its naphtha splitter and depentanizer to recover more medium-weight hydrocarbons: weighing a new deisopentanizer column, a side-cut revamp, and a DWC, the dividing-wall option produced high-purity iC5 for premium (RON 90) gasoline without extra reboiler energy while reusing most existing equipment — matching a two-column sequence’s recovery and purity at far lower capital cost.