A meta-heuristic approach for heat-integrated distillation sequence synthesis with nonsharp splits and thermal coupling

The synthesis of multicomponent separation systems is an important field in process engineering. Separation systems such as distillation trains have high energy demands. Hence, strategies for mitigating energy requirements in these processes are fundamental. Therefore, methods that can yield heat-integrated distillation sequences (HIDiS) are useful for reducing energy-related expenses in an industrial plant. This work presents an improved meta-heuristics-based framework for the synthesis of HIDiS encompassing nonsharp splits and intensification strategies such as thermal coupling and nonsharp distillation columns with side streams. The method is based on a sequence of two bi-level optimization strategies: one for the distillation sequence with simultaneous implicit heat integration (via multi-utility Pinch Analysis based approach) and one for the explicit heat exchanger network synthesis. Results show that considering the aforementioned options in HIDiS synthesis leads to more economically efficient configurations than in simpler heat-integrated configurations (e.g., sharp splits, no column stacking). Solutions achieved in literature case studies outperformed previous works by 8.3 % and 5.2 %.