Optimal retrofit of a side stream column to a dividing wall column for energy efficiency maximization

• Systematic methodology for optimal retrofit of a side distillation column to a DWC.
• Minimum energy requirement is effectively utilized for feasibility study.
• Optimal designs are efficiently done by response surface methodology.
• The retrofitted DWC reduces energy requirement by 25.16%.
• Large potential for retrofitting a side stream column to a DWC.

A side distillation column is widely used to separate multicomponent mixtures into three products. However, this kind of column consumes considerable amounts of energy due to thermodynamic restrictions and the nature of the distillation process. Retrofit of the side distillation column to a dividing wall column (DWC) can result in significant energy savings. This study evaluated a systematic method for optimal retrofit of a side stream column to a DWC. The minimum energy requirement for the separation of a multicomponent mixture was used for a feasibility study. Subsequently, design and optimization was performed using shortcut, rigorous and response surface methodology. One case study was illustrated to demonstrate the proposed methodology. The results showed that the optimal retrofit of a side distillation column to the DWC could not only save a significant amount of energy, but also increase the capacity. This study highlights the potential for retrofitting a side stream column to a DWC from a techno economic point of view.