Vapor-liquid Equilibrium Data For Binary Systems Research Articles

Development of a novel MW-VLE model for calculation of vapor–liquid equilibrium under microwave irradiation

Microwave (MW) irradiation can intensify the vapor–liquid separation of polar/non-polar binary system mixtures, but its industrialization requires vapor–liquid equilibrium (VLE) data in microwave field. Therefore, a novel MW-VLE model was proposed to predict the VLE data of binary systems in microwave fields by using system thermodynamic properties, dielectric properties, and electric field strength. For modeling, first, the influence of thermodynamic and dielectric properties on microwave-induced relative volatility change (MIRVC) was investigated experimentally in detail. It indicated that increasing the system dielectric loss difference, boiling temperature difference, and decreasing the thermal conductivity can enhance the effect of MIRVC. Then, the model characteristic parameters were obtained by fitting the VLE curves with/without microwave irradiation. Afterwards, the empirical correlation equations of MW-VLE were derived by correlating model characteristic parameters with mentioned above factors and electric field strength. Finally, the model predictions well agreed with the experimental results of PrOH-PP and IPA-EA systems within 10% error, verifying the model accuracy.

Measurement and correlation of vapor–liquid equilibrium data for binary and ternary systems composed of (−)-β-caryophyllene, p-cymene and 3-carene at 101.33 kPa

Abstract New experimental vapor–liquid equilibrium (VLE) data for three binary systems composed of p-cymene + (−)-β-caryophyllene, 3-carene + (−)-β-caryophyllene, and 3-carene + p-cymene and for the ternary system of (−)-β-caryophyllene + p-cymene + 3-carene were obtained using a modified Ellis equilibrium still over the temperature range from 444.44 to 528.78 K at 101.33 kPa. The compositions of these mixtures were assessed using gas chromatography. The VLE data for the binary systems passed thermodynamic consistency tests based on the Herington method and Van Ness test. The thermodynamic consistency of the ternary system was checked by a Van Ness test. The VLE data for binary systems were correlated using the Wilson, NRTL, and UNIQUAC activity coefficient models with minor deviations. The ternary VLE data were also satisfactorily correlated using the Wilson, NRTL and UNIQUAC models. By comparing the experimental values for the ternary system with the values calculated using the three models, the average absolute deviation of the equilibrium temperature and vapor–phase composition were determined to be less than 0.57 K and 0.0060, respectively. These results indicated excellent agreement of the models with experimental values.

Isobaric Vapor–Liquid Equilibrium for the Binary and Ternary System with Isobutyl Alcohol, Isobutyl Acetate and Dimethyl Sulfoxide at 101.3 kPa

The isobaric vapor–liquid equilibrium (VLE) data for the binary systems isobutyl alcohol + dimethyl sulfoxide (DMSO), isobutyl acetate + DMSO, and ternary system isobutyl alcohol + isobutyl acetate + DMSO were measured at 101.3 kPa. All of the binary VLE data passed Wisniak’s modifed Herington area test and Wisniak point and area test. Ternary VLE data passed Wisniak point test. The VLE data of binary systems were correlated with NRTL, UNIQUAC, and Wilson models. The ternary VLE behavior were successfully predicted by the correlated binary parameters. The VLE data for the binary and ternary systems predicted by the correlated interaction parameters were in good agreement with all the experimental data. The relative volatility of isobutyl acetate to isobutyl alcohol can be greatly increased by DMSO and the azeotropic point of isobutyl acetate and isobutyl alcohol will disappear if the mole fraction of DMSO is greater than 0.36. DMSO is a promising solvent for separating the azeotrope of isobutyl alcohol an...

An improved static–analytic apparatus for vapor–liquid equilibrium (PTxy) measurement using modified in-situ samplers

An improved apparatus based on the static-analytic method for reliable vapor–liquid equilibrium (VLE) data measurement is presented in this work. It has been applied to investigate systems containing organic sulfur compounds. New sampling mechanisms were combined with ROLSI™ capillary samplers to achieve on-line sampling for both vapor and liquid phases in a pressure range between 0.1 and 10 bar. Phase samples were directly sent to a gas chromatograph for composition analysis. The equipment was tested against other commonly used experimental methods in this pressure range on the (n-butane + ethanol) and (diethyl sulfide + ethanol) systems. The obtained data were correlated by Wilson model and compared with existing data. The improved apparatus has shown comparable performances to existing methods, while showing some advantages such as complete PTxy phase measurements and less product consumption. After the validation step, additional VLE data for binary systems of interest, (diethyl sulfide + n-butane) and (1-pentanethiol + 1-pentanol), were reported and modeled in this work.

Prediction of phase equilibrium of CO2/cyclic compound binary mixtures using a rigorous modeling approach

Vapor liquid equilibrium (VLE) data has significant role in designing processes which include vapor and liquid in equilibrium. Since it is impractical to measure equilibrium data at any desired temperature and pressure, particularly near critical region, thermodynamic models based on equation of state (EOS) are usually used for VLE estimating. In recent years due to the development of numerical tools like artificial intelligence methods, VLE prediction has been find new alternatives.In the present study a novel method called Least-Squares Support Vector Machine (LSSVM) used for predicting bubble/dew point pressures of binary mixtures containing carbon dioxide (CO2)+cyclic compounds as function of reduced temperature of the system, critical pressure, acentric factor of the cyclic compound, and CO2 composition. A 333 binary equilibrium data points of CO2 and six cyclic compounds within temperature and pressure ranges of 308.15–473.15K and 0.5–27.71MPa were used to develop the model. Results show that the proposed model is able to predict VLE data for binary systems containing supercritical or near-critical CO2/cyclic compounds with an acceptable average absolute relative deviation percent (AARD%) of 3.9381% and the coefficient of determination (R2) value of 0.9980. For detection of the probable doubtful experimental data, and applicability of the model, the Leverage statistical approach performed on the data sets. This algorithm showed that the proposed LSSVM model is statistically valid for VLE prediction and the whole phase equilibrium data points are in applicability domain of the model.

Isobaric Vapor−Liquid Equilibria of Heptane + 1-Butanol and Heptane + 1-Pentanol Systems at (53.3 and 91.3) kPa

Isobaric vapor−liquid equilibrium (VLE) data have been determined at (53.3 and 91.3) kPa for the binary mixtures of heptane + 1-butanol and heptane + 1-pentanol. The VLE data of binary systems were found to be thermodynamically consistent. In addition, the experimental VLE data were correlated by using the Wilson, nonrandom two-liquid (NRTL), and universal quasi-chemical (UNIQUAC) activity coefficient models for the liquid phases. The binary interaction parameters of the activity coefficient models have been determined and reported. A comparison of model performances has been made by using the criterion of the average absolute deviation (AAD) in boiling-point and vapor-phase composition. The obtained results indicate that the used activity coefficient models satisfactorily correlate the VLE data of the studied systems.

Phase equilibria at superatmospheric pressures for systems containing halohydrocarbon, aromatic hydrocarbon, and alcohol

The vapor-liquid equilibrium (VLE) data for four binary and two ternary systems concerning chloroform, benzene, ethanol, and 1-butanol are determined at pressures from 101.3 to 303.0 kPa. The experimental VLE data of binary systems are correlated with the Wilson equation, and those at relevant pressures for ternary systems are predicted with the three-component Wilson equation in which the parameters are taken from the corresponding binary systems. Minimum boiling azeotropes are found for chloroform + ethanol, ethanol + benzene, and benzene + 1-butanol only at 303.0 kPa. In the presence of alcohols, chloroform decomposes at T > 400 K, so the experimental investigation cannot be completed for chloroform + alcohol containing systems at higher pressures.