Extractive Heterogeneous Azeotropic Distillation (EHAD) is a separation technique designed for non-ideal mixtures exhibiting azeotropic behaviour, capable of achieving separations that are difficult or impossible to achieve with conventional distillation. Unlike conventional extractive distillation, which typically requires external entrainers, the distinguishing feature of this study is the exclusive use of water as an auto-entrainer, eliminating the need for additional chemicals, simplifying operational procedures, and enhancing the sustainability of the process. A defining characteristic of EHAD is the relatively small temperature difference between the top and bottom of the distillation column. This narrow thermal profile governs heat and mass transfer, directly influences entropy generation, and affects overall thermodynamic efficiency, while providing a suitable basis for energy integration and process intensification.

The applicability and performance of EHAD are investigated through a case study involving the separation and recycling of a quaternary mixture of water, ethanol, ethyl acetate, and methyl ethyl ketone from the waste stream of a printing firm, representing a complex system with multiple azeotropes. A rigorous process simulation is conducted using Aspen modelling software in conjunction with detailed entropy generation and exergy analyses to evaluate thermodynamic performance, identify inefficiencies within the configurations, and quantify losses throughout the process. Process-intensification strategies, including heat integration and heat-pump coupling, are explored to reduce energy consumption and minimize thermodynamic irreversibilities. Entropy generation analysis is used to determine dominant sources of energy degradation, while exergy analysis quantifies thermodynamic losses and allows for the calculation of exergy efficiency across different configurations.

Results indicate that energy integration reduces the total energy demand by approximately 57% compared to non-integrated operation, significantly lowering both entropy generation and exergy destruction. The overall exergy efficiency of the integrated EHAD process reaches 35%, demonstrating the thermodynamic advantages of the approach. The findings highlight that using water as an auto-entrainer enables EHAD to achieve energy-efficient, thermodynamically optimized separation of complex azeotropic mixtures, offering strong potential for sustainable industrial applications in the chemical and pharmaceutical sectors.