A modified UNIFAC group-contribution model for prediction of phase equilibria and heats of mixing

Larsen, Bent L.; Rasmussen, Peter; Fredenslund, Aage

doi:10.1021/ie00071a018

Cited by 838 publications

(674 citation statements)

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“…In the present study, PSRK mixing rule has been used with the PSRK version of UNIFAC model proposed by Fredenslund et al [38] and modified in such a way that binary interaction coefficients between functional groups depend on temperature [35,39] and with UNIQUAC activity coefficient model [40,41]. In a same way, MHV2 mixing rule is used with the Lingby version of UNIFAC [42]. When UNIQUAC model is used in the mixing rule, two binary interaction coefficients (A ij and A ji ) have to be fitted on experimental data.…”

Section: Phase Equilibrium Modelingmentioning

confidence: 99%

Phase equilibrium of the CO2/glycerol system: Experimental data by in situ FT-IR spectroscopy and thermodynamic modeling

Medina-González

Tassaing

Camy

et al. 2013

The Journal of Supercritical Fluids

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OATAO is an open access repository that collects the work of Toulouse researchers and makes it freely available over the web where possible. This is an author-deposited version published in : http://oatao. a b s t r a c tPhase equilibrium experimental data for the CO 2 /glycerol system are reported in this paper. The measurements were performed using an in situ FT-IR method for temperatures ranging from 40 • C to 200 • C and pressures up to 35.0 MPa, allowing determination of the mutual solubility of both compounds. Concerning the CO 2 rich phase, it was observed that the glycerol solubility in CO 2 was extremely low (in the range of 10 −5 in mole fraction) in the pressure and temperature domains investigated here. Conversely, the glycerol rich phase dissolved CO 2 at mole fractions up to 0.13. Negligible swelling of the glycerol rich phase has been observed. Modeling of the phase equilibrium has been performed using the Peng-Robinson equation of state (PR EoS) with classical van der Waals one fluid and EoS/G E based mixing rules (PSRK and MHV2). Satisfactory agreement was observed between modeling results and experimental measurements when PSRK mixing rules are used in combination with UNIQUAC model, although UNIFAC predictive approach gives unsatisfactory representation of experimental behavior.

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Section: Phase Equilibrium Modelingmentioning

confidence: 99%

Phase equilibrium of the CO2/glycerol system: Experimental data by in situ FT-IR spectroscopy and thermodynamic modeling

Medina-González

Tassaing

Camy

et al. 2013

The Journal of Supercritical Fluids

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“…The UNIFAC (Fredenslund et al, 1977;Fredenslund et al, 1975;Larsen et al, 1987) group contribution method and the ASOG (Kojima and Tochigi, 1979) model were used in previous papers Susial et al, 1989) for the prediction of the VLE of isobaric data at pressures near atmospheric. This paper evaluates the behaviour in the prediction of VLE data by the different versions of UNIFAC and the ASOG group contribution models with respect to the experimental data obtained in this study at moderate pressures.…”

Section: Results and Treatmentmentioning

confidence: 99%

“…These data were used to check the reliability of UNIFAC (Fredenslund et al, 1977;Fredenslund et al, 1975;Gmehling et al, 1993;Larsen et al, 1987) and ASOG (Kojima and Tochigi, 1979) group contribution models in order to expand the applicability of these predictive models.…”

Section: Introductionmentioning

confidence: 99%

Vapor-liquid equilibrium measurements for the binary system methyl acetate+ethanol at 0.3 and 0.7 MPa

Badajoz

Rios-Santana

Sosa-Rosario

2011

Braz. J. Chem. Eng.

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-This paper reports experimental data of the isobaric vapor-liquid equilibria (VLE) for the mixture methyl acetate + ethanol at 0.3 and 0.7 MPa, determined using a copper still ebulliometer. The activity coefficients obtained from the experimental data were correlated by using different thermodynamic mathematical models. All the binary systems show a positive consistency when subjected to the point-to-point test of Van Ness. The prediction of VLE data obtained with the UNIFAC and ASOG methods has been verified with experimental data.

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“…The UNIFAC method is one of the most common methods applied to much research on the ethanol distribution over the aqueous and organic phases. In this study, the ordinary 14) and modified 15) UNFAC methods were used to predict the distribution behaviors. The UNIFAC method cannot easily estimate the activity coefficients of high polar components, such as water, in many cases.…”

Section: Resultsmentioning

confidence: 99%

“…Firstly the methodology of solvent selection was used to identify preferable solvents and the liquid-liquid equilibria of ethanol in the system of ethanol, water and the selected solvent were experimentally measured at 298.15 K. The experimental results were compared with the liquid-liquid equilibria estimated by the ordinary 13), 14) and modified 15) UNIFAC models. The extraction behaviors were also analyzed with respect to the ethanol distribution and separation selectivity.…”

Section: Introductionmentioning

confidence: 99%

Extraction Equilibrium of Ethanol for Bioethanol Production — Solvent Selection and Liquid-liquid Equilibrium Measurement —

Habaki

Tabata²,

Kawasaki

et al. 2010

J. Jpn. Petrol. Inst.

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Ethanol distributions between selected organic and aqueous phases were measured for recovery and concentration of bioethanol from fermented solution. The strategy of solvent selection was based on the background of biofuel production, and m-xylene was selected as the primary solvent and capric acid, 1-hexanol and 2-ethyl hexanol secondary solvents were utilized to enhance the ethanol solubility. The extraction performance was evaluated through the liquid-liquid equilibrium. m-Xylene showed low distribution coefficient of ethanol and high separation selectivity of ethanol relative to water. All secondary solvents increased the distribution coefficient. The separation selectivity was greatly reduced by capric acid, but was similar for 1-hexanol and 2-ethyl hexanol. The two phase region was smaller for 1-hexanol than for 2-ethyl hexanol, chosen as the best secondary solvent. Examination of the effects of 2-ethyl hexanol concentration in the solvent found that a small amount of 2-ethyl hexanol could enhance the distribution coefficient and maintain the separation selectivity constant. The measured liquid-liquid equilibria were estimated with the ordinary and modified UNIFAC methods. Both methods could predict the liquid-liquid equilibrium behaviors of the measured systems, but the modified UNIFAC method could show a better correlation. However, the water concentrations in the organic phases were estimated to be larger than the measured values if the measured concentrations were very low.

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A modified UNIFAC group-contribution model for prediction of phase equilibria and heats of mixing

Cited by 838 publications

References 5 publications

Phase equilibrium of the CO2/glycerol system: Experimental data by in situ FT-IR spectroscopy and thermodynamic modeling

Phase equilibrium of the CO2/glycerol system: Experimental data by in situ FT-IR spectroscopy and thermodynamic modeling

Vapor-liquid equilibrium measurements for the binary system methyl acetate+ethanol at 0.3 and 0.7 MPa

Extraction Equilibrium of Ethanol for Bioethanol Production — Solvent Selection and Liquid-liquid Equilibrium Measurement —

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