Designing a Packed Dividing Wall Column for an Aromatics Processing Plant

Abstract

This paper introduces a comprehensive design method assembled using facilities of a commercial software package that complemented by Excel programs, which contain own column dimensioning and well established cost estimation procedures, enables proper assessment of the industrial viability of a dividing wall column (DWC) equipped with corrugated sheet structured packings. The heart of the performance simulation tool is a detailed four-column model that in conjunction with a simple, theoretically founded short-cut method providing reliable initial values for liquid and vapor splits and a simple but effective objective function for design optimality indication allows determination of the adequate stage and reflux requirement of a DWC. The proposed dimensioning method enables a close approach in accuracy to that required at the stage of conceptual design for purposes of making a bid by an equipment manufacturer. Compared to a two-columns-in-series configuration, as employed in an aromatics processing complex within a refinery, a DWC equipped with state-of-the-art structured packing and auxiliary internals requires approximately 43% less energy to deliver three fractions at required product specifications. This, accompanied by savings of nearly 51% based on total annualized costs, indicates that implementing a DWC could lead to a significant increase in profitability of aromatics processing plants.