Phase equilibria for reactive distillation of diethyl succinate. Part II: Systems diethyl succinate+ethyl acetate+water and diethyl succinate+acetic acid+water

This work shows a new approach to the parameter-fitting problem useful in the solutions thermodynamic field, providing a more objective framework to obtain better empirical/semiempirical models for chemical engineering applications. A model based on the excess Gibbs energy function g E is used to represent the behavior of real solutions, together with its first derivative h E, using a combined modeling under the paradigm of multiobjective optimization. The problem is formulated as an MINLP methodology to simultaneously consider two aspects: the model complexity and the best parametrization to prevent the overfitting, controlling the trade-off between them by applying the Akaike Information Criterion to g E residuals. Two different solvers, one deterministic (SBB/CONOPT) and another evolutionary (GA), are used, and their ability to solve the problem is analyzed. The designed methodology is applied to three highlighted VLE cases in chemical engineering, and the results obtained show the ability of the method to get the best model in each case. The proposed methodology proved useful for modulating the number of parameters considering the imposed requirements, which decrease as the accuracy requirements for h E are relaxed. The efficient-fronts obtained show a small trade-off region, noting that the proposed framework provides the simplest models with the minimum completeness uncertainty.

Section: Dataset Descriptionmentioning

confidence: 99%

The Parametrization Problem in the Modeling of the Thermodynamic Behavior of Solutions. An Approach Based on Information Theory Fundamentals

Sosa

Fernández

Ortega

et al. 2019

“…Presently, some VLE data on these associating systems were dealt with the regular strategies of correlation and prediction in the previous literature. − The associating systems were also implemented to study the thermodynamic properties in aqueous salt solution by many researchers. − The ethanoic acid associating systems were computed in the systems susceptible to chemical reaction under atmospheric pressure or isothermal condition. − …”

Section: Introductionmentioning

confidence: 99%

Combined Experimental and Theoretical Studies on the Prediction of the Isobaric Vapor–Liquid Association Phenomena for Binary and Ternary Mixtures of Water, Ethanoic Acid, and Propanoic Acid

Zhang

Kwon

et al. 2020

It is a considerable challenge for the phase behavior of chemical separation industry to correlate and predict the vapor–liquid equilibria (VLE) data of the binary and ternary systems containing associating components because it is not known how these forms exist in the experimental condition, such as homogeneous or heterogeneous dimers or trimers, even polymers, and so on. Herein, VLE data for the associating ternary system, water + ethanoic acid + propanoic acid, and the three-constituent binary systems have been measured by different liquid-phase compositions using a Fischer ebulliometer at 101.33 kPa. The structures and distribution of various clusters in water, ethanoic acid, and propanoic acid systems were fully optimized at the B3LYP/6-31+G(d) level of theory using Gaussian 09. Then, we developed a strategy that could calculate the liquid activity coefficients by considering the distribution of the associating components in the strong association systems. This method is called the discrete clusters (DC) model, and, for comparison, Wilson, NRTL, and UNIQUAC models were employed to correlate the VLE data for the three-constituent binary systems. Also, the VLE data of the ternary system were estimated from the DC, Wilson, NRTL, and UNIQUAC models without any additional adjustment. Our DC model, which considered the explicit number of various clusters, showed better agreement and a smaller deviation from the experimental data. These VLE data derived from the DC model can be used for the design and simulation of the distillation behavior of the binary and ternary association systems.

“…Isobaric VLE data for the ethanol (1) + water (2) + [EMIM] + [Ac] − (3) system at 101.3 kPa. ■, experimental data from the literature; ●, experimental data from the literature; ▲, experimental data from the literature; dashed line, predicted results by the UNIFAC-Lei model with x 3 = 0; solid line, predicted results by the UNIFAC-Lei model with x 3 = 0.2.…”

Section: Results and Discussionmentioning

confidence: 99%

Separation of the Methanol–Ethanol–Water Mixture Using Ionic Liquid

Dong

Dai

Lei

2018

Vapor pressure data for the binary systems (water/methanol/ethanol + 1-ethyl-3-methylimidazolium acetate ([EMIM]+[Ac]−)) and the ternary systems (methanol + water + [EMIM]+[Ac]−, ethanol + water + [EMIM]+[Ac]−, and methanol + ethanol + [EMIM]+[Ac]−) were measured by a modified equilibrium still. For the above systems, the maximum average relative deviation between experimental data and the UNIFAC-Lei model predicted values was 7%, confirming the prediction accuracy of the UNIFAC-Lei model. Thus, this model was further used to predict the isobaric vapor–liquid equilibrium (VLE) data at 101.3 kPa for the methanol + water + [EMIM]+[Ac]−, ethanol + water + [EMIM]+[Ac]−, and methanol + ethanol + [EMIM]+[Ac]− systems at a fixed mole fraction of ionic liquid (IL) (x IL = 0.2). It was demonstrated that the ionic liquid [EMIM]+[Ac]− was an appropriate entrainer to separate the methanol–ethanol–water mixture. On this basis, the extractive distillation process was simulated using the rigorous equilibrium (EQ) stage model. The results showed that the entrainer consumption, the heat duty of total reboilers, and the heat duty of total condensers decrease by 25, 6, and 6%, respectively, when [EMIM]+[Ac]− replaces the conventional entrainer ethylene glycol (EG). Furthermore, the σ-profiles and excess enthalpies obtained by the COSMO-RS model provided theoretical insights into the separation mechanism at the molecular level.