Aspen plus simulation-assisted vacuum distillation process optimization via response surface methodology (RSM): High-purity recovery of extractant from complex mixed phenolic raffinate and its industrial feasibility

• Addressed multi-component azeotropic interference/thermal sensitivity in phenol raffinate extractant recovery; overcame traditional distillation’s 6–12-month cycle and high cost. • Proposed Aspen Plus-RSM integrated simulation-optimization with “shortcut→rigorous” strategy, improving design accuracy and efficiency. • Determined sieve tray column optimal parameters: >99.5 % extractant recovery, thermal decomposition avoidance, and enhanced gas-liquid mass transfer. • Achieved significant economic benefits: 27.3 % lower annual operating cost than ether-based schemes; process cycle shortened to 1–2 months. • Provided theoretical support and quantitative design basis for industrial scale-up of phenol raffinate extractant recovery, with prominent engineering value. Extractant recovery from phenol raffinate faces critical challenges: multi-component azeotropy, thermal sensitivity of target components, and traditional distillation’s limitations (semi-empirical models, 6–12-month development cycles, high costs). This is industrially important as efficient extractant recycling and thermal decomposition avoidance directly determine process economics and product quality. Novelty lies in integrating Aspen Plus simulation with Response Surface Methodology (RSM) for multi-factor optimization, coupled with a "shortcut-to-rigorous" strategy (DSTWU to RadFrac) to enhance design accuracy—going beyond previous studies that lacked systematic optimization or ignored cross-method synergy. Methods include establishing sieve tray distillation models, optimizing key parameters (operating pressure, feed conditions, reflux ratio) via RSM, and comparing two extractants (cyclohexane, isopropyl ether). Key results: >99.5 % extractant recovery for both systems, complete avoidance of thermal decomposition, and sieve tray optimization boosting gas-liquid mass transfer. The cyclohexane-based scheme reduces annual operating costs by 27.3 % vs. isopropyl ether, with the development cycle shortened to 1–2 months. Conclusions: The integrated "simulation-optimization" approach provides a robust, cost-effective solution for phenol raffinate extractant recovery, laying a reliable foundation for industrial scale-up with significant engineering application value.