Optimal design of reduced vapor transfer dividing wall structures with and without heat integration

Abstract A dividing wall column (DWC) is a prime example of process intensification, whereby significant energy and cost savings can be achieved for some systems compared to operation in conventional design of two columns in series. It has been theorized that the vapor and liquid thermal coupling streams in the DWC could be replaced by liquid‐only transfer streams, making the DWC unit less complex. The ultimate structure is the liquid‐liquid (LL) structure with all thermal coupling streams replaced and a dividing wall extending from the top to the bottom. This article compares the separation and economic performances of the regular DWC and the LL structure, and further investigates the benefits of heat‐integrated alternatives of both (combined condenser and reboiler, double‐effect, vapor recompression assisted). Optimization uncovered that vapor recompression assisted structures exhibit substantial energy savings and lowered total annualized cost but that the savings depend on electricity and utility costs.