Study of Thermodynamic Modeling of Isothermal and Isobaric Binary Mixtures in Vapor-Liquid Equilibrium (VLE) of Tetrahydrofuran with Benzene (303.15 K) Cyclohexane (333.15 K), Methanol (103 kPa), and Ethanol (100 kPa)

Tetrahydrofuran (THF) is an aprotic solvent with multiple applications in diverse areas of chemical, petrochemical, and pharmaceutical industries with an important impact in chemical waste liquid with other solvents. In this work, 51 available VLE data, for isothermal binary mixtures of THF(1) + Benzene(2) and THF(1) + Cyclohexane(2) at 303.15 and 333.15 K, respectively, and isobaric THF(1) + Methanol(2) at 103 kPa and THF(1) + Ethanol(2) at 100 kPa were used in the development of the activity coefficient models. The quality of experimental data was checked using the Herington test. VLE binary data was correlated with models Wilson, NRTL UNIQUAC, and UNIFAC to obtain binary parameters and activity coefficients. The best thermodynamic consistency when conducting the Herington test for the VLE data was found for the THF(1) +Cyclohexane(2) isothermal system and THF(1) + Ethanol(2) isobaric system. The UNIQUAC model for isothermal systems THF(1) + Benzene(2) and THF(1) + Cyclohexane(2), the NRTL model for the isobaric system THF(1) + Methanol(2), and the UNIQUAC model for THF(1) + Ethanol(2) perform better than the other models.

Vapour-Liquid Equilibrium Study for the Carbon Dioxide and Hydrogen Sulphide in Deionized Water and NaCl Aqueous Solution at Temperature from 373.15 to 423.15 K

New vapour liquid equilibrium (VLE) data for carbon dioxide (CO2) and hydrogen sulphide (H2S) mixture in deionized water and NaCl aqueous solution are generated at temperature range from 373.15 to 423.15 K and pressure up to 25.0 MPa. A static-analytic type method, taking advantage of two magnetic capillary samplers for phase sampling is used for this VLE measurements. The VLE data generated in this work are compared against literature data, Duan model and the simplified cubic plus association (CPA-SRK72) Equation of State (EoS) model predictions. From the results, it is demonstrated that the CPA-SRK72 EoS model is able to predict the phase behaviour of CO2 and H2S in water and NaCl aqueous solutions with low absolute average deviation (AAD) against the measured experimental data.

Vapor−Liquid Equilibrium For The Mixture of m-Xylene, Ethylbenzene and 1, 2, 4-Trichlorobenzene at 101.3 kPa

The vapor-liquid phase equilibrium (VLE) data for binary systems of m-xylene + ethylbenzene, m-xylene + 1, 2, 4-trichlorobenzene, ethylbenzene + 1, 2, 4-trichlorobenzene and ternary system of m-xylene + ethylbenzene + 1, 2, 4-trichlorobenzene were determined with a modified Rose still at 101.3 kPa, and all the binary data passed the Wisniak’s test, which accorded with the thermodynamic consistency. Three activity coefficient models namely, Wilson, NRTL and UNIQUAC were used to correlate VLE data and get binary interaction parameters, then the ternary VLE data of m-xylene + ethylbenzene + 1, 2, 4-trichlorobenzene were estimated based on these model parameters using Aspen Plus software. The estimation values of the three models agree well with the experimental data. Moreover, the effect of 1, 2, 4-trichlorobenzene was analyzed, and it found to be an effective candidate extractant for the extractive distillation of ethylbenzene from mixed xylenes.

Sensitivity of the Non-Equilibrium Approach for Mixture Condensation to Heat and Mass Transfer Correlations and Thermophysical Properties

The prediction of mixture condensation is still complex due to coupled heat and mass transfer and insufficient data of thermophysical mixture properties. This article analyzes the impact of various heat and mass transfer correlations on the non-equilibrium approach for mixture condensation in a vertical plain tube. Furthermore, the influence of thermophysical properties from different databases is investigated. The results are shown for ethanol-water, but allow conclusions to other fluid mixtures. They indicate that the liquid heat transfer coefficient in the non-equilibrium approach dominates the qualitative behavior of the condensation process, but the vapor mass transfer coefficient can only decrease or increase the quantitative level of the effective heat transfer with minor impact. More importantly, the logarithm in the vapor mass transfer term is central for the prediction of the condensation heat transfer. As this logarithm contains VLE data, it proves that there is a strong connection between VLE and overall prediction of mixture condensation. A demonstration of available data for thermophysical mixture properties of ethanol-water shows significant deviations, which affect the calculations as well. Besides, data from our own experiments are presented for mixture viscosity of ethanol-water. It is recommended to focus not only on improved heat and mass transfer correlations, but also on thermophysical properties and VLE data for a precise prediction of mixture condensation.

Measurement and Correlation of Isobaric Vapor-Liquid Equilibrium Data for Water + 2-Azido-N,N-Dimethylethanamine System at 4 kPa

Isobaric vapor-liquid equilibrium (VLE) data for binary system of water + 2-azido-N,N-dimethylethanamine (DMAZ) was measured at 4 kPa. The results showed an azeotropic point at x1 = 0.985 and T = 302.17 K. The data was correlated with nonrandom two-liquid (NRTL), Wilson and universal quasi-chemical activity coefficient (UNIQUAC) models for the liquid phase. A comparison of the model performances was made using of the criterion of the average absolute deviation, standard deviation and mean standard deviation in boiling-point temperature. The results indicated that the NRTL activity coefficient model satisfactorily correlated the VLE data.

Predictions of the vapor-liquid equilibrium data for low-GWP Hydrofluorocarbons + polyethylene-glycol dimethylether solvents by modified UNIFAC model

The working fluids are crucial for developing the absorption refrigeration system. Our previous work has proposed three novel working pairs, which uses the low-GWP HFCs (R32, R152a and R161) as the refrigerants and the polyethylene-glycol dimethylether solvent DMETEG as the absorbent. To explore the VLE behaviors of HFCs in other longer chain structures of polyethylene-glycol dimethylether solvents, the modified UNIFAC (Dortmund) model was applied for prediction. The previous binary parameters showed large deviations from the experimental data. Then the new binary parameters were obtained by regression. For R32+DMEDEG and R152a/R161+DMETrEG, the prediction ARAD results were reduced from 17.13%, 24.06% and 12.48% to 3.71%, 2.61% and 6.86%, respectively. Finally, the VLE data of R161 + PGDE at the temperatures of 293.15-343.15K were predicted.

Improvement of Component Flux Estimating Model for Pervaporation Processes

Separating non-ideal mixtures by pervaporation (hence PV) is a competitive alternative to most traditional methods, such as distillation, which are based on the vapour–liquid equilibrium (VLE). It must be said, in many cases, accurate VLE data are already well known in the literature. They make the method of PV modelling a lot more complicated, and most of the viable models are (semi)empirical and focus on component flux (Ji) estimation. The pervaporation model of Mizsey and Valentinyi, which is based on Rautenbach’s works, is further improved in this work and tested rigorously by statistical means. Until now, this type of exponential modelling was only used for alcohol–water mixtures, but in this work, it was extended to an ethyl acetate–water binary mixture as well. Furthermore, a flowchart of modelling is presented for the first time in the case of an exponential pervaporation model. The results of laboratory-scale experiments were used as the basis of the study and least squares approximation was used to compare them to the different model’s estimations. According to our results, Valentinyi’s model (Model I) and the alternative model (Model III) appear to be the best methods for PV modelling, and there is no significant difference between the models, mainly in organophilic cases. In the case of the permeation component, Model I, which better follows the exponential function, is recommended. It is important to emphasize that our research confirms that the exponential type model seems to be universally feasible for most organic–water binary mixtures. Another novelty of the work is that after PDMS and PVA-based membranes, the accuracy of the semiempirical model for the description of water flux on a PEBA-based membrane was also proved, in the organophilic case.

New Fitting Method for Vapour-Liquid Equilibrium Data and its Application for Ethanol-Water Distillation Process Modeling

For modeling and simulation of distillation processes, the main information required is the vapour-liquid equilibrium (VLE) data. These are available as discrete values, but for modeling purpose, an analytical function would be more suitable. We developed a simple calculation protocol to obtain a single continuous function for the VLE curve on the entire concentration domain, without using thermodynamic functions. The fitting parameters of binary ethanol-water mixture VLE curve were determined. The methodology is suitable for fitting continuous functions on VLE data of any binary or multicomponent, non-ideal (even azeotropic) mixtures.