Multi-objective optimization of a cascade system for 136Xe enrichment via microchannel distillation

To address the significant limitations of conventional distillation methods in xenon isotope separation, this study proposes a cascade distillation system for 136Xe enrichment based on MCD (Microchannel Distillation) technology. First, the relative volatilities among xenon isotopes were precisely calculated. A virtual component model was developed in Aspen HYSYS and validated against experimental data to ensure its accuracy and reliability. Then, the operational parameters of the MCD unit were analyzed, and the optimal operating pressure and reflux ratio for a single-stage system were identified. The effects of the feed-to-product flow rate ratio on 136Xe enrichment efficiency, recovery rate, and reboiler power consumption were also investigated. Finally, a cascade distillation model was developed, and its operating parameters were optimized through a combination of uniform design, stepwise quadratic regression, the NSGA-III multi-objective optimization algorithm, and the TOPSIS decision-making method. The optimized system significantly reduced power consumption and increased the 136Xe abundance from 8.670 % to 13.612 %, while reducing the total reboiler power consumption by 8.42 %.This study demonstrates that the MCD-based cascade distillation system effectively overcomes the limitations of conventional methods, such as low separation efficiency and high energy consumption. It offers a novel and efficient approach for 136Xe enrichment with both theoretical and practical significance.