Insight into the trade-off among economics, controllability, and resilience in pressure-swing distillation systems

Pressure-swing distillation (PSD) is an effective technique for separating azeotropes, yet it faces limitations due to high energy consumption and complex dynamic controllability. Heat integration (HI) enhances PSD's energy efficiency but diminishes control degrees of freedom (CDOF) and undermines process safety. This study adopts a resilience-based perspective to assess and enhance PSD control performance. Focusing on the partially heat-integrated PSD (PSD-PHI) system for methanol/acetone separation, rigorous simulations compare conventional (PSD-CONV) and heat-integrated alternatives with various control structures. Resilience is quantitatively evaluated via a previously developed framework, highlighting the impacts of process designs and controls. The PSD-CONV with independent pressure control shows superior resilience but the highest total annual cost (TAC). The economically favorable CS2 scheme, using pressure-compensated temperature control (PCTC), exhibits poor resilience from limited pressure deviation mitigation. Incorporating hot vapor bypass or auxiliary condenser boosts resilience to conventional levels while reducing energy use and TAC by 11–20%. Comprehensive trade-off analysis integrating economics, controllability, and resilience identifies CS5 as optimal for balanced performance and CS6 for stringent pressure stability. This resilience-integrated methodology supplements traditional economic-controllability assessments, providing a holistic framework for PSD. With industrial applicability, it enables chemical enterprises to achieve energy-efficient, safe distillation for low-carbon resilience.