Process-driven Solvent Screening for Efficient Extractive Distillation Using Interpolative Rational Functions published in Chemical Engineering Science
Process-driven Solvent Screening for Efficient Extractive Distillation Using Interpolative Rational Functions
Sahil Sethi, Xiang Zhang, Kai Sundmacher
We are thrilled to announce that Sahil Sethi's latest research paper, "Process-driven Solvent Screening for Efficient Extractive Distillation Using Interpolative Rational Functions," has been published in the prestigious journal Chemical Engineering Science!
About the research topic: This groundbreaking study introduces a novel multilevel methodology for solvent screening, revolutionizing extractive distillation by replacing complex and nonlinear thermodynamic vapor-liquid equilibrium (VLE) models with simple yet reliable surrogate models using interpolative rational functions. This innovation significantly accelerates process optimization, reducing the solution time of rigorous Mixed-Integer Nonlinear Programming (MINLP) problems from hours to mere minutes or seconds, enabling the efficient evaluation of multiple solvents. The study’s results are transformative, with the optimal solvent identified achieving a 27.9% reduction in total annualized cost compared to Sulfolane, the current industry standard for separating ethylbenzene/styrene mixtures.
When designing extractive distillation processes, using selectivity and capacity at infinite dilution alone is hard to identify the real optimal solvent with minimal process cost. To overcome this problem, a new process-driven solvent screening approach is developed. As simple and reliable surrogate models, rational functions (algebraic fractions such that the numerator and the denominator are polynomials) and multivariate polynomials (a subset of rational functions) are trained to interpolate vapor–liquid equilibria with thermodynamic consistency. The surrogate models can directly be embedded into superstructure-based extractive distillation process design to obtain optimal solutions within a few seconds. This enables to evaluate the real process performance of numerous solvents efficiently. Incorporating the accelerated process design strategy, a multi-level solvent screening framework is proposed and exemplified for the separation of a close-boiling mixture ethylbenzene/styrene. The solvent C2H2Br4 ultimately enables a cost reduction of 27.9 % compared to the industrially used benchmark solvent sulfolane.
Sahil extends his heartfelt gratitude to his co-authors, Xiang Zhang and Kai Sundmacher, for their invaluable contributions, and acknowledges the IMPRS for Advanced Methods in Process and Systems Engineering for funding his PhD and supporting this transformative research. This work represents a significant leap forward in process systems engineering and offers scalable solutions for the chemical industry.
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