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In the recent years, the need to improve the thermodynamic models, particularly making them more precise and predictable for complex systems, has increased [Industrial Requirements for Thermodynamics and Transport PropertiesHendriksE. Hendriks, E. Ind. Eng. Chem. Res.2010491113111141 Industrial Requirements for Thermodynamic and Transport PropertiesKontogeorgisG. Kontogeorgis, G. Ind. Eng. Chem. Res.20216049875013 The complexity of electrolyte systems is due to the strong interactions between ions, the hydration forces that take place during salt dissociation, and the physical forces at high concentrations of solute. Consequently, the existing thermodynamic electrolyte models show some limitations and are far from being completely optimized for industrial simulations. Thermodynamics based on electrolyte mixtures and mixed solvents requires further development and research [PolingB. E. Poling, B. E. The Properties of Gases and LiquidsMcGraw-Hill Education2001The EleTher Joint Industrial Project (JIP) aims at promoting research in this field. A practical workflow is under development where the first stage consists in analyzing the data. The present work is part of this larger scope and presents a strategy to analyze the internal and external consistency of experimental data for electrolyte mixtures. The focus is on alkali halide salts in water. Internal consistency allows testing the quality of data by confronting them to each other and using the thermodynamic relationships between these data. For that purpose, the data are confronted with a model that was initially optimized and the deviations are analyzed. For this purpose, the electrolyte non-random two-liquid (eNRTL) thermodynamic model was selected. Some deviations are attributed to the model inadequacy (high temperature or high molalities). Others are to be attributed to data inconsistencies. On the other hand, the objective of external consistency is to evaluate the consistency between different systems of the same family. The Bromley model is used for this purpose, as it contains a single adjustable parameter. Investigating the trend of this parameter with type of compound or with temperature may provide valuable information regarding the underlying physics, in addition to identifying outliers.

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A new approach for the feasibility analysis of reactive distillation processes based on the reactive extractive curve maps (rExCM) concept is introduced. A method dedicated to reactive distillation feasibility analysis, and design has been developed in our team since 1999. From minimal information concerning the physicochemical properties of the system, three steps lead to the design of the unit and the specification of its operating conditions. Currently, the procedure permits the conceptual design of hybrid reactive column configuration with one or two feed plates, for any number of equilibrium reactions (provided that the degree of freedom of the system is equal to 2) occurring in liquid or vapor phase. This contribution focuses on the most recent developments: the generalization of the feasibility analysis step to double‐feed processes thanks to the introduction of the rExCM concept. This methodology is illustrated through two examples: the emblematic methyl acetate example and the production of dimethyl methyl glutarate. © 2011 American Institute of Chemical Engineers AIChE J, 58: 2346–2356, 2012

Résumé -Étude de faisabilité de l'estérification d'un diacide par distillation réactive -Cette étude propose une approche systématique de la conception d'une colonne à distiller réactive. Elle a été appliquée avec succès au cas peu étudié des réactions consécutives. L'estérification de l'acide 2 methyl glutarique par le méthanol a été traitée. Les 3 premières étapes de la méthode montrent la faisabilité de la production dans une colonne hybride avec un taux de reflux faible et la nécessité de travailler avec un excès de méthanol. Ces résultats théoriques ont ensuite été consolidés par un pilotage sur une colonne de diamètre 75 mm. Dans tous les régimes pilotés, les résultats obtenus sont significativement supérieurs à un réacteur en lit fixe même avec des excès de réactif plus importants. Abstract -Feasibility Study of Diacid Esterification by Reactive Distillation

This work describes a new non-ideal shortcut method for distillation design and includes a graphical representation. Based on the operation leaves of Castillo et al. (1998) the method uses production segment rather than completely specified product which eliminates any sensitivity to the composition of the minor products. It has two aims. The first is to determine if a specified separation respects the mass balance and the thermodynamic feasibility. The second one is to find the minimum reflux ratio and a preliminary design of the column. The following mixtures are investigated: an ideal mixture of ethanol, n-propanol, and n-butanol; a non-ideal mixture of acetone, water, and acetic acid; and an azeotropic mixture of acetone, isopropanol, and water. Designs obtained with this new method lead to purity and recovery rate close to specifications which is sometimes impossible with conventional ideal shortcut like the well-known Fenske-Underwood-Gilliland shortcut.

OATAO is an open access repository that collects the work of some Toulouse researchers and makes it freely available over the web where possible.

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