Binary Vapor-liquid Equilibrium Data Research Articles

Isobaric Vapor-Liquid Equilibrium Data for Tetrahydrofuran + Acetic Acid and Tetrahydrofuran + Trichloroethylene Mixtures.

Vapor-liquid equilibrium (VLE) data for the binary systems tetrahydrofuran (THF) + acetic acid (AA) and THF + trichloroethylene (TCE) were measured under isobaric conditions using an ebulliometer. The boiling temperatures for the systems (THF + AA/THF + TCE) are reported for 13/15 compositions and five/six different pressures ranging from 50.2/60.0 to 101.1/101.3 kPa, respectively. The THF + AA system shows simple phase behavior with no azeotrope formation. The THF + TCE system does not exhibit azeotrope formation but seems to have a pinch point close to the pure end of TCE. The nonrandom two-liquid (NRTL) and universal quasichemical (UNIQUAC) activity coefficient models were used to accurately fit the binary (PTx) data. Both models were able to fit the binary VLE data satisfactorily. However, the NRTL model was found to be slightly better than UNIQUAC model in fitting the VLE data for both systems. The results can be used for designing liquid-liquid extraction and distillation processes involving mixtures of THF, AA, and TCE.

Separation of ethylene glycol, 1,2‐butanediol and 1,2‐propanediol with azeotropic distillation

Abstract1,2‐butanediol (1,2‐BDO) and 1,2‐propanediol (1,2‐PDO) are inevitably side produced in the ethylene glycol (EG) production processes from non‐petroleum routes, but are very difficult to separate by the ordinary distillation method because of the closeness of their boiling temperatures to EG, thus compromise the economy of these processes. The azeotropic distillation process using 1‐octanol (CPO) as an entrainer to separate EG and 1,2‐BDO mixture with or without 1,2‐PDO was studied in this paper. Four binary vapour–liquid equilibrium data of EG‐1,2‐BDO, EG‐CPO, 1,2‐BDO‐CPO, and 1,2‐PDO‐CPO were measured using an Ellis equilibrium kettle and regressed with the thermodynamic model of non‐random two liquid to obtain the corresponding binary interaction parameters. On this basis, azeotropic distillations with CPO as an entrainer were designed to separate EG and 1,2‐BDO with or without 1,2‐PDO. The complete separation processes, including the azeotropic distillation and CPO recovery process consisting of extraction with H2O and subsequent distillation, were simulated and optimized with Aspen Plus for both the EG‐1,2‐BDO binary mixture and the EG‐1,2‐BDO‐1,2‐PDO ternary mixture. The simulation results show that the azeotropic distillation method with CPO as an entrainer can effectively separate the mixture of EG‐1,2‐BDO and EG‐1,2‐BDO‐1,2‐PDO, achieving EG of 99.90% purity with 99.98% recovery and 1,2‐BDO of 99.30% purity with 99.45% recovery for the binary mixture, and achieving EG of 99.90% purity with 99.80% recovery, 1,2‐BDO of 99.35% purity with 99.35% recovery, and 1,2‐PDO of 90.59% purity with 94.38% recovery for the ternary mixture. These processes are promising for industrial application and can significantly improve the economy of non‐petroleum EG production.

Density, viscosity, saturated vapor pressure, and isobaric vapor–liquid equilibrium for 4‑fluoronitrobenzene and 2-fluoronitrobenzene

Density and viscosity data of pure liquid 4‑fluoronitrobenzene and 2‑fluoronitrobenzene were determined in the temperature range from 303.15 to 353.15 K at the local atmospheric pressure of 100.8 kPa. Saturated vapor pressures of the two isomers and isobaric vapor–liquid equilibrium (VLE) data for the binary system of the two isomers at 10.0 kPa were measured experimentally by a modified Rose still. The relationship of density to temperature is accurately correlated by the DIPPR equation. The viscosity data were well described by the Litovitz, Ghatee, VFT, and Andrade equations. Among them, Andrade equation shows the best accuracy. Both Antoine and Riedel equations can successfully correlate the relationship between saturated vapor pressure and temperature, while Riedel equation is more accurate due to the small average relative deviation. The binary VLE data were correlated with NRTL and Wilson models, and the binary interaction parameters were obtained. The VLE data predicted by the obtained parameters are in good agreement with the experimental data, and the binary system did not exhibit azeotropic behavior. The thermodynamic properties of the pure components described above and the vapor–liquid equilibrium data provided are critical for the design and operation of the distillation of the isomeric mixture of 4‑fluoronitrobenzene + 2-fluoronitrobenzene.

Vapor-liquid equilibrium of acid gases with imidazolium-based ionic liquids using the UMR-PRU model

The UMR-PRU group contribution equation of state (EoS), which couples the Peng-Robinson EoS with UNIFAC via the Universal Mixing Rules, is extended to pure imidazolium-based ionic liquids (ILs), as well as to their mixtures with CO2 and H2S. The studied ILs consist of alkyl-methylimidazolium cations and tetrafluoroborate, hexafluorophosphate and bis(trifluoromethylsulfonyl)imide anions. The EoS parameters of pure ionic liquids, are determined by fitting experimental vapor pressure and liquid density data. For the extension of UMR-PRU to binary CO2/IL and H2S/IL mixtures, the model parameters are determined by fitting experimental binary vapor-liquid equilibrium data of acid gases with ionic liquids. For comparison, the Peng-Robinson coupled with the conventional van der Waals one-fluid mixing rules (vdW1f) is also applied to the same systems, using adjustable attractive and co-volume cross interaction parameter. It is shown that Peng-Robinson accurately describes pure ionic liquid vapor pressures and liquid densities, while UMR-PRU yields very satisfactory vapor-liquid equilibrium results for binary and ternary mixtures containing ILs and acid gases. Overall, UMR-PRU yields much better results than Peng-Robinson coupled with the vdW1f mixing rules, which indicates the superiority of the UMR mixing rules over the vdW1f ones.

Calculation of azeotropic properties for binary mixtures with the PC-SAFT equation of state

In this work, we present a novel approach to predict the location of azeotropes for binary mixtures using the perturbed-chain statistical associating fluid theory equation of state (PC-SAFT).The proposed method requires as input the pure-component parameters of the PC-SAFT equation: the segment number (m), the hard-core segment diameter (σ), and the segment-segment interaction energy parameter (ε/k) for every pure non-associating fluid. By using these parameters, PC-SAFT estimates with accuracy the azeotropes properties of binary mixtures as well as the successful prediction of vapour-liquid equilibria for many non-associating binary systems. In order to improve the predictive ability of the PC-SAFT equation, the interaction parameters of 8 binary systems containing novel refrigeration fluid, were estimated from binary vapour–liquid equilibrium data. For comparison, the data were also modelled using the (PR-MC-WS-NRTL) thermodynamic model. Good agreements are found between the calculated results and reference data and the relative error does not exceed 3.69% and 0.97% for the molar fraction and the pressure respectively.

Vapor pressure curves and isobaric vapor–liquid equilibrium for binary systems with compounds obtained from glycerol to be used as components of a bio-diesel mixture

The search of new renewable fuels and the interest of finding new uses for the abundant subproducts of many industrial processes have prompt Eni S.p.A to develop a technology for producing biofuels from glycerol. One of the compounds involved in this process is 2-ethyl-4-ethoxymethyl-1,3‑dioxolane (PrEDO). In this paper their temperature - vapor pressure curve has been determined experimentally as well as binary vapor–liquid equilibrium data at different pressures of systems where this compound is involved.The experimental vapor pressure data of PrEDO have been fitted with the Antoine equation. The vapor liquid equilibrium data have been correlated and calculated with UNIFAC, UNIQUAC, NRTL and Wilson to analyze their use when designing distillation processes.

Vapor-liquid equilibrium and topological analysis of ethyl propionate synthesized by reaction distillation

Isobaric vapor–liquid equilibrium (VLE) data were measured for the binary systems propionic acid (1) + ethanol (2), propionic acid (1) + ethyl propionate (2) and propionic acid (1) + water (2) at 101.3 kPa. The Wilson, NRTL and UNIQUAC models were used to fit the binary VLE data. All the three models are applicable to all the binary systems. The binary interaction parameters were obtained by the regression of the experimental data, which can be used to describe the phase behavior of the quaternary system effectively. The phase equilibrium model was used to calculate the ternary and quaternary residue curve maps, and the topological analysis was performed. The results show that the obtained parameters and the thermodynamic model can be further used to model the reactive distillation process of ethyl propionate synthesis.

Vapor-liquid equilibrium experiment and extractive distillation process design for the azeotrope ethyl propionate n-propanol using ionic liquid

Ionic liquid 1-ethyl-3-methylimidazolium acetate ([Emim][OAC]) and organic solvent ethylene glycol (EG) were evaluated for their performance to disrupt the ethyl propionate and n-propanol azeotrope through the phase equilibrium experiment. Isobaric vapor–liquid equilibrium (VLE) data of ethyl propionate + n-propanol, ethyl propionate + n-propanol + [Emim][OAC] and ethyl propionate + n-propanol + EG was measured at atmospheric pressure. The experimental apparatus and procedure were confirmed for reliability by comparing the binary experimental VLE data to published data. The NRTL model was employed to correlate the VLE data and predict the phase equilibrium behavior of systems. The results demonstrated that the separation performance of [Emim][OAC] is more excellent than EG, and the more ionic liquid is added, the better the separation performance. The simulation of the extractive distillation process using [Emim][OAC] as entrainer was developed via Aspen Plus software. The optimal operating variables were determined by reducing the total annual cost (TAC) to a minimum. Finally, the economic assessment analysis indicated that the TAC of optimal operating conditions is 803.39 k$ and the feasibility of the extractive distillation scheme to separate azeotropic systems.

New association schemes for tri-ethylene glycol: Cubic-Plus-Association parameterization and uncertainty analysis

Transportation of natural gas extracted from subterranean reservoirs is subject to several risks introduced by the presence of water. These risks can be mitigated through subsea dehydration, the design of which requires an accurate understanding of the thermodynamics of these systems. Having previously investigated the use of mono-ethylene glycol as a dehydration agent, this research focusses on the industry workhorse: tri-ethylene glycol (TEG). The Cubic-Plus-Association (CPA) equation of state has previously provided a good description for systems of equal complexity and in this work the literature 4C and 6D association schemes, as well as four newly proposed association schemes (4F, 5F, 6F and 5C) are evaluated for the description of TEG. These association schemes, which are explained in the manuscript, represent different ways of self-association for TEG.Pure component parameters are estimated by fitting to vapor pressure, liquid density, and liquid-liquid equilibrium data, with statistical uncertainty analysis implemented to determine the confidence intervals of the parameters. Binary interaction parameters are similarly fitted to binary vapor-liquid equilibrium (VLE) data. Optimized parameters are evaluated by testing their performance in predicting binary and ternary VLE systems.Due to the strong influence of certain experimental data sets, the literature 6D parameters are shown to be unsuitable for the applications in this work. The need for consistent experimental data quantifying both vapor and liquid phases, specifically for TEG – CH4 has been highlighted. The best overall performance was obtained using the newly proposed 4F association scheme. Along with improved overall description of various VLE and LLE systems, with average absolute relative deviations generally between 2-20%, single parameter sensitivity analysis shows improved optimality for several systems also not included in the parameterization. This is indicative of a better fundamental characterization of the TEG molecule. The value of the uncertainty analysis is shown for the binary interaction parameters, where for TEG – CH4 VLE a temperature-dependent correlation is shown to be unnecessary using the optimum association schemes.

Isobaric Binary Vapor–Liquid Equilibrium of Ethanol + Glycerol and 1-Propanol + Glycerol Systems at 16.0 and 101.3 kPa

The isobaric binary vapor–liquid equilibrium data of ethanol + glycerol and 1-propanol + glycerol systems were collected experimentally at two pressure levels of 16.0 and 101.3 kPa using modified G...

Isobaric vapor-liquid equilibrium of methanol + glycerol binary mixture at 31.3 kPa

In this study the binary vapor-liquid equilibrium (VLE) data of methanol + glycerol system were determined experimentally of using modified Glass Otmher - Still. The equilibrium compositions of liquid and vapor phases were analysis using refractometer index type Bausch and Lomb ABBE. The experimental data obtained in this work were thermodynamically consistent based on the area test. The experimental data were correlated well with the Wilson and Non Random Two Liquid (NRTL) and Universal Quasi-Chemical (UNIQUAC) models. The performance of Universal Chemical Functional Group Activity Coefficients (UNIFAC) in predicting VLE of the system studied were evaluated as well.

Solubility of benzyl alcohol in supercritical carbon dioxide, comparison of literature data and thermodynamic modelling

Benzyl alcohols are an important class of aromatic alcohols used in the fine chemical and pharmaceutical industries which can be found in extracted bio-oils produced from the thermochemical liquefaction of lignocellulosic biomass.Equation-of-state (EOS) models can be used to describe the vapour-liquid equilibrium (VLE) to support supercritical fluid extraction (SFE) studies of key compounds from bio-oils, but ideally require experimentally determined binary VLE data at appropriate conditions of temperature and pressure.In this study, high-pressure solubility data of benzyl alcohol in supercritical carbon dioxide (scCO2) is reported. Data has been determined experimentally at temperatures of 313 K, 333 K and 353 K and at pressures up to 284 bar. Data was used to validate and support existing published solubility data. It was shown that the literature VLE data regression to the Peng-Robinson-Boston-Mathias (PR-BM) model was good in fitting benzyl alcohol solubility data determined both in this study and in previous literature.

Experimental isobaric vapour-liquid equilibrium data for binary systems of {sec-butyl acetate (SBAC) + acetamide} and {sec-butyl alcohol (SBA) + acetamide} and the ternary system of (SBAC + SBA + acetamide) at 101.3 kPa

Isobaric vapour - liquid equilibrium (VLE) data for the binary systems of sec-butyl acetate (SBAC) + acetamide and sec-butyl alcohol (SBA) + acetamide and the ternary system of SBAC + SBA + acetamide were measured at 101.3 kPa using a modified Othmer still. The thermodynamic consistency tests for the experimental data were checked by Van Ness point test and Wisniak’s L-W method. The experimental VLE data of the binary systems were correlated with NRTL, Wilson and UNIQUAC activity coefficient models. The results indicate that the binary and ternary VLE data predicted by the three models agree well with the experimental data. And the ‘pseudo-azeotropic’ phenomenon of sec-butyl acetate + sec-butyl alcohol mixture can be eliminated by acetamide.

Isobaric Vapor-Liquid Equilibria for Binary System of Ethanol (1) + Eugenol (2) at 400 and 760 mmHg

Eugenol is the main component of clove oil, while the main impuritis of it is β-caryophyllene. Eugenol with a purity higher than 98% has a higher price than low purity eugenol. Thus, further eugenol purification process is needed. Common purification processes are extraction and distillation. In the design and simulation of the distillation process it requires a knowledge of Vapor-Liquid Equilibrium (VLE) data from a mixture of components to be separated (eugenol and ethanol) as the result of extraction process. In this work, the experimental VLE data were measured for binary mixtures of ethanol(1) + eugenol(2) at 400 and 760 mmHg. The apparatus used for this experiment is an othmer still equipped with a vacuum pump and a manometer. The experiments were performed to obtain equilibrium data (T), component concentrations in liquid phase (x), and in vapor phase (y). The binary VLE data were correlated with the Wilson, NRTL and UNIQUAC models to obtain the binary parameters. The reliability of these models were tested by comparing with experimental results using Root Mean Square Deviation (RMSD). For the system and the operation condition studied, the Wilson, NRTL and UNIQUAC models suited well and give satisfactory results based on the RMSD values .

Isobaric Vapor-Liquid Equilibria for Binary System of Ethanol (1) + Eugenol (2) at 400 and 760 mmHg

Eugenol is the main component of clove oil, while the main impuritis of it is β-caryophyllene. Eugenol with a purity higher than 98% has a higher price than low purity eugenol. Thus, further eugenol purification process is needed. Common purification processes are extraction and distillation. In the design and simulation of the distillation process it requires a knowledge of Vapor-Liquid Equilibrium (VLE) data from a mixture of components to be separated (eugenol and ethanol) as the result of extraction process. In this work, the experimental VLE data were measured for binary mixtures of ethanol(1) + eugenol(2) at 400 and 760 mmHg. The apparatus used for this experiment is an othmer still equipped with a vacuum pump and a manometer. The experiments were performed to obtain equilibrium data (T), component concentrations in liquid phase (x), and in vapor phase (y). The binary VLE data were correlated with the Wilson, NRTL and UNIQUAC models to obtain the binary parameters. The reliability of these models were tested by comparing with experimental results using Root Mean Square Deviation (RMSD). For the system and the operation condition studied, the Wilson, NRTL and UNIQUAC models suited well and give satisfactory results based on the RMSD values .

Experimental isobaric vapour-liquid equilibrium data for the binary system (N, N-dimethyl acetamide + dimethyl sulfoxide) and the quaternary system (sec-butyl acetate + sec-butyl alcohol + N, N-dimethyl acetamide + dimethyl sulfoxide) at 101.3 kPa

Isobaric vapour-liquid equilibrium (VLE) data for the binary system of {N, N-dimethyl acetamide (DMAC) + dimethyl sulfoxide (DMSO)} and the quaternary system of {sec-butyl acetate (SBAC) + sec-butyl alcohol (SBA) + DMAC + DMSO} were measured at 101.3 kPa using a modified Othmer still. The thermodynamic consistency test for the binary experimental data was checked by Van Ness point test. The experimental VLE data of the binary system were correlated with Wilson, NRTL and UNIQUAC activity coefficient models. The binary and quaternary VLE data predicted by the binary interaction parameters agreed well with the experimental data. And the mixed solvent (DMAC + DMSO) can eliminate the pseudo-azeotrope of SBAC and SBA. Thus the mixture of (DMAC + DMSO) is a potential extractive solvent in the separation of the pseudo-azeotrope of SBAC and SBA by extractive distillation.

Measurement and Correlation of Isobaric Vapor Liquid Equilibrium Data for Cyclopentyl Methyl Ether and Cyclopentanol

Isobaric vapor–liquid equilibrium data for pure components cyclopentyl methyl ether (CPME) and cyclopentanol (CP) and their binary mixtures was generated using a modified ebulliometer. This data has been reported for five different pressures in the range of 71.50 to 101.79 kPa. Pure component boiling points were correlated using the Antoine equation and compared with the literature data. Binary vapor–liquid equilibrium data was modeled using Wilson, NRTL, and UNIQUAC models. Deviation plots for experimental and predicted temperatures are given. UNIQUAC and NRTL model predictions showed a better fit with the experimental values relative to the Wilson model.

Experimental and predicted vapor–liquid equilibrium for binary systems with diethanolamine, m-cresol and p-cresol at 20.0 kPa

Isobaric vapour–liquid equilibrium (VLE) data for two binary systems of p-Cresol (PC) + diethanolamine (DEA) and m-Cresol (MC) + DEA were measured at 20.0 kPa. The Herington area method was used to check the binary VLE data, and the results showed good thermodynamic consistency. Meanwhile, the Wilson, NRTL, UNIQUAC models and the chemistry theory proposed by Dolezalek were used to correlate the VLE data. The binary energy interaction parameters for activity models, and reaction equilibrium constants for chemistry theory were obtained. With help of the parameters obtained in this work, the NRTL model was used to predict the VLE data of the two binary systems at the pressure of 8.33 kPa. The predictive results were compared with the literature’s data. At same time, the excess Gibbs free energy for the two binary systems, and infinite dilution activity coefficients for MC and PC in DEA were estimated. The calculated results showed that the DEA had slightly stronger interaction with PC than MC.

Isobaric Vapor–Liquid Equilibrium for Binary and Ternary Systems of 2-Methoxyethanol, Ethylbenzene, and Dimethyl Sulfoxide at 100.00 kPa

The isobaric vapor–liquid equilibrium (VLE) data for the binary systems 2-methoxyethanol + ethylbenzene, ethylbenzene + dimethyl sulfoxide (DMSO), and 2-methoxyethanol + DMSO and the ternary system 2-methoxyethanol + ethylbenzene + DMSO were measured with a Fischer VLE 602 apparatus at 100.00 kPa. The VLE data for all the binary and ternary systems were thermodynamically consistent and passed the Wisniak’s L–W test. The binary VLE data were correlated with the Wilson, nonrandom two-liquid, and universal quasichemical models with minor deviations. The ternary VLE data predicted from the corresponding binary interaction parameters agreed well with the experimental data. The azeotropic temperature and composition of the 2-methoxyethanol and ethylbenzene azeotropic mixture at 100.00 kPa were 391.05 K and 60.15 mol % 2-methoxyethanol, respectively. Additionally, the azeotrope disappeared after adding DMSO, which confirms that DMSO can serve as a prospective entrainer for separating 2-methoxyethanol from ethylb...

A model for predicting flash point of alkane-alkane and water-alcohol mixtures by the Cubic-Plus-Association Equation of State

A vapor-pressure-based model has been constructed to predict the closed-cup flash points of binary miscible mixtures. The model utilizes a cubic-plus-association (CPA) equation of state (EoS) to thermodynamically describe the behavior of both liquid and vapor phases. The alkane-alkane and water-alcohol mixtures were selected to examine the predictive potential of the model. Compared to known models, which use the activity coefficient models, the proposed flash point calculation procedure has fewer binary interaction parameters (BIPs) and does not need the Antoine equation to calculate the vapor pressure of pure components. Moreover, another advantage is that by utilizing the published experimental flash point data, no binary vapor-liquid equilibrium (VLE) data are required to obtain the BIPs.