(441c) Process Intensification Framework for Extractive Separation Systems

The separation of azeotropic mixtures to achieve a higher purity beyond the azeotrope point is a frequent but challenging task in chemical processes. Extractive separation, a classic process intensification invention, offers the solution to overcome the physical equilibrium by introducing an extra mass separating agent (i.e., entrainer) [1-3]. Thus, the entrainers play a key role in these processes due to: (i) their solubility properties to enhance the system’s mass transfer driving force to drive separation, and (ii) their hazardous properties (e.g., toxicity, flammability) for environmental and safety considerations.

Recent advances in the synthesis of process intensification systems have been leveraging phenomenological representation methods to systematically generate process solutions without pre-postulation of plausible equipment-based flowsheets which may hinder the discovery of novel design configurations [4-6], which also provides the opportunity to investigate the effect of functional materials at phenomenal level from process fundamental perspective [7]. However, the operational performances (e.g., flexibility, safety, controllability) in the resulting intensified designs, which are crucial to practical implementation, are mostly neglected at this synthesis stage [8]. Therefore, a holistic approach for the synthesis of extractive separation systems, with simultaneous consideration of entrainer selection and operability assessment, is still lacking.

To address this challenge, we have recently developed a systematic framework for the synthesis of operable process intensification systems [9], which features: (i) process synthesis, integration, and intensification using phenomena-based Generalized Modular Representation Framework (GMF) [10] to derive optimal design configurations, (ii) integrated steady-state operability and inherent safety considerations [11], and (iii) simultaneous design and control with explicit model-based predictive control strategies following the PAROC (PARametric Optimization and Control) framework [12]. In this work, we apply the proposed framework to synthesize enthanol/water extractive separation processes with guaranteed operability, safety, and controllability performances. Two entrainer candidates are considered and examined with respect to process profitability, safety, and environmental considerations: a conventional entrainer ethylene glycol (EG) and an ionic liquid entrainer 1-ethyl-3-methyl-imidazolium acetate ([EMIM][OAc]). Mass and/or heat integration are also simultaneously explored to reduce energy consumption, resource utilization, and waste production.

Reference

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