Systematic Strategy for Obtaining a Dividing-Wall Column Applied to an Extractive Distillation Process

Currently, process intensification using dividing-wall columns (DWCs) is one of the most promising alternatives for reducing the costs of the distillation process. However, for extractive distillation, there are still questions regarding whether the DWC is a more economical option than the conventional sequence (CS). Normally, extractive DWCs are simulated with two thermally coupled columns (TCSs), and their designs are usually obtained by setting the TCSs in different ways that do not necessarily constitute an optimum design. Thus, this work proposes a systematic procedure based on stage equilibrium for obtaining an optimized DWC configuration, in terms of operability and design. A strict comparison between the DWC configuration and the CS (also optimized) was performed, and the best results in terms of the total annual cost (TAC) were obtained for columns with a distinct number of stages in each section of the wall; however, these columns did not outperform the optimized conventional systems.