Phase equilibria and critical phenomena in fluid (n-alkane + water) systems at high pressures and temperatures

Loos, Theo W. de; Dorp, J.H. van; Lichtenthaler, R. N.

doi:10.1016/0378-3812(83)80041-7

Cited by 51 publications

(48 citation statements)

References 8 publications

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“…As one can see from these figures, the derived critical temperatures and pressures are in fair agreement with the data reported by other authors. The present result is in satisfactory agreement with the interpolated values calculated from the data by de Loos et al 6 and Brunner. 7 For example, the derived values of the critical pressure (P C ) 75.50 MPa) and the critical temperature (T C ) 646.30 K) for the concentration of x ) 0.115 mole fraction of n-C 5 H 12 are in satisfactory (within 1.4 MPa and 0.4 K) agreement with the values 76.90 MPa and 646.7 K, reported by de Loos et al 6 for very close (0.118 mole fraction) to the present concentration.…”

Section: Resultssupporting

confidence: 95%

“…The qualitative comparison between the T S -P S data reported by de Loos et al 6 (the reported data presented only graphically) and the present data for three selected concentrations is presented in Figure 11. As Figure 11 shows, in general, the agreement between the present results and the data reported by de Loos et al 6 is satisfactory. We determined the phasetransition pressures and temperatures by "straight" extrapolations of the isochore behavior before and after phase transition occurs.…”

Section: Resultsmentioning

confidence: 81%

“…The critical curves of H 2 O + n-alkane mixtures show typical gas-gas equilibria of the second type. 6,7 The critical parameters for the water + n-pentane mixture has been also measured by Connolly 8 and Roof. 9 The critical point is defined by Connolly 8 as the minimum temperature for the mixing of two components in all proportions as a liquid or as the maximum temperature of a binary system for two liquid phases in equilibrium.…”

Section: Review Of Available Experimental Datamentioning

confidence: 99%

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PVTx Measurements of Water−n-Pentane Mixtures in Critical and Supercritical Regions

Расулов

Abdulagatov

2010

J. Chem. Eng. Data

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The PVTx properties of H 2 O + n-C 5 H 12 mixtures have been measured in the near-and supercritical regions. Measurements were made along 66 liquid and vapor isochores in the density range from (63 to 713) kg · m -3 , at temperatures from (303 to 684) K, and at pressures up to 63 MPa. Measurements were made for eight concentrations between 0.0270 and 0.8898 mole fractions of n-C 5 H 12 . The temperatures and pressures at the three-phase (liquid-liquid-gas) and two-phase (liquid-gas) boundary curves for the H 2 O + n-C 5 H 12 mixtures were obtained using the isochoric (P-T) break point technique. The expanded uncertainty of the density, pressure, and temperature measurements at the 95 % confidence level with a coverage factor of k ) 2 is estimated to be 0.12 % (at high densities) to 0.15 % (at low densities), (0.0005 to 0.03) MPa, and 15 mK, respectively. The critical property (P C ,T C ) data of the upper and lower branches of the critical curves were extracted from the derived phase-boundary data. The measured three-phase data were used to estimate the value of the upper critical end point. The value of the Krichevskii parameter was calculated from the direct measured PVTx and the derived critical property data.

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Section: Resultssupporting

confidence: 95%

Section: Resultsmentioning

confidence: 81%

Section: Review Of Available Experimental Datamentioning

confidence: 99%

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PVTx Measurements of Water−n-Pentane Mixtures in Critical and Supercritical Regions

Расулов

Abdulagatov

2010

J. Chem. Eng. Data

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“…They found that the critical curve of the mixture starts at the critical point of pure water (T C ) 647.1 K and P C ) 22.1 MPa) and runs via a temperature minimum at T m ) 627.8 ( 0.2 K and P m ) 31 ( 2 MPa to higher pressures. They showed also that the critical line changes systematically with the carbon number of the n-alkane 43,44,46 (see Figures 2 and 3). The temperature of the disappearance of the second fluid phase was measured to accuracy within (0.1 K. The pressure was measured with accuracy within (0.02 MPa at pressures up to 40 MPa and (0.05 MPa at higher pressures.…”

Section: Mixturesmentioning

confidence: 91%

PVTx Measurements and Crossover Equation of State of Pure n-Hexane and Dilute Aqueous n-Hexane Solutions in the Critical and Supercritical Regions

Abdulagatov

Базаев

Magee

et al. 2005

Ind. Eng. Chem. Res.

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The PVTx relationship of aqueous n-hexane solutions (0.0201, 0.082, and 0.8500 mole fraction of n-hexane) has been measured in the near-critical and supercritical regions with a constantvolume piezometer. Measurements were made on the critical isotherm of pure water 647.1 K with pressures ranging from 8 to 33 MPa. The total uncertainties of density, pressure, temperature, and composition measurements are estimated to be less than 0.16%, 0.05%, 15 mK, and 0.001 mole fraction, respectively. The Krichevskii parameter was estimated (124.4 ( 20 MPa) from direct measurements of the P-x dependence along the critical isotherm-isochore of pure water. The measured PVTx data were used to calculate partial molar volumes at infinite dilution for n-hexane V h 2 ∞ in near-critical water. The asymptotic behavior of the partial molar volume along the solvent's (pure water) critical isotherm-isobar was studied. The molar volume values for the dilute H 2 O + n-C 6 H 14 mixture along the critical isotherm-isochore of pure water were also used to estimate the critical exponent of partial molar volume V h 2 ∞ ∝ x -( ) 0.795 ( 0.001). Using our new PVTx data together with data obtained in other studies, we developed a crossover Helmholtz free-energy model (CREOS) for dilute aqueous n-hexane solutions in wide temperature and pressure ranges around the vapor-liquid critical points. The CREOS model requires only the critical locus as an input and represents all available experimental PVTx data for a dilute H 2 O + n-C 6 H 14 mixture with an average absolute deviation (AAD) of about 0.50-0.65% in the temperature and density ranges 0.98T c (x) e T e 1.15T c (x) and 0.35F c (x) e F e 1.65F c (x), respectively, and concentrations up to 0.05 mole fractions of n-hexane. The accuracy and predictive capability of the crossover model was confirmed by comprehensive comparison of present crossover EOS for the pure n-hexane with the available experimental data in the critical and supercritical regions.

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“…The effect of n-alkane chain length on phase equilibria has received considerable experimental attention [62][63][64][65]. Gas-gas immiscibility of the second kind exists for all the n-alkanes although the results of Tsiklis and Maslennikova [66] describing immiscibility of the first kind for n-butane + water seem to be incorrect.…”

Section: Water + N-alkane Mixturesmentioning

confidence: 99%

Phase equilibria in water containing binary systems from molecular based equations of state

Aparicio-Martinez

Hall

2007

Fluid Phase Equilibria

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Phase equilibria and critical phenomena in fluid (n-alkane + water) systems at high pressures and temperatures

Cited by 51 publications

References 8 publications

PVTx Measurements of Water−n-Pentane Mixtures in Critical and Supercritical Regions

PVTx Measurements of Water−n-Pentane Mixtures in Critical and Supercritical Regions

PVTx Measurements and Crossover Equation of State of Pure n-Hexane and Dilute Aqueous n-Hexane Solutions in the Critical and Supercritical Regions

Phase equilibria in water containing binary systems from molecular based equations of state

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