Elsevier

Fluid Phase Equilibria

Volume 318, 25 March 2012, Pages 96-101
Fluid Phase Equilibria

Vapor–liquid equilibrium measurement and thermodynamic modeling of binary systems (methane + n-tetradecane)

https://doi.org/10.1016/j.fluid.2012.01.023Get rights and content

Abstract

The vapor–liquid equilibrium (VLE) data for binary system of methane + n-tetradecane at four temperatures T = 295, 324, 373, and 448 K were measured using a designed pressure–volume–temperature (PVT) apparatus. The phase composition and density and viscosity of saturated liquid phase were measured for pressures up to 10 MPa. The experimental VLE data were compared with the modeling results obtained using the Peng–Robinson and Soave–Redlich–Kwong equations of state. Two approaches, a single temperature-independent interaction parameter and temperature-dependent interaction parameter, were considered to fit the generated experimental data.

Highlights

► Vapor–liquid equilibrium properties over wide range of pressure (2–10 MPa). ► Binary system of methane + n-tetradecane at T = 295, 324, 373, and 448 K. ► Experimental measurements, density, viscosity, and composition, using a designed PVT apparatus. ► The experimental data were modeled using the Peng–Robinson and Soave–Redlich–Kwong equations of state.

Introduction

The thermodynamic behavior of binary and multi-components systems, including hydrocarbons, is of considerable interest in the design and development of many industrial processes, such as enhanced oil recovery methods and the processing of petroleum products. Moreover, the knowledge of the phase behavior of the fluids becomes important at certain stages of the many industrial processes, especially in the cases that the operational conditions change. This would be certainly of vital importance when the mixtures of volatile components and heavy normal hydrocarbons have been considered.

The non-ideal behavior in binary systems containing hydrocarbons with greatly different molecular sizes has gained less attention while these systems provide the information for the description of the phase behavior of multi-component systems. The present study was attempted to measure the phase equilibrium properties (solubility, density, and viscosity) of hydrocarbon mixtures that contain components of greatly different volatilities. From reservoir and production prospective, the density and viscosity are of especial importance because they determine the fluid flow properties as well as estimation about the total mass of reserves.

In the past, some experimental studies on the phase behavior of binary systems containing methane and heavy normal hydrocarbons have been reported. Ng et al. [1] reported low pressure solubilities of light hydrocarbons, methane, ethane, propane, ethylene, and propylene, in octadecane, eicosane, and docosane in the temperature region 30–200 °C (303–473 K). Cukor and Prausnitz [2] measured Henry's constants for methane, ethane, and hydrogen in n-hexadecane, bicyclohexyl and diphenylmethane for the temperature range 25–200 °C (298–473 K) using a new gas solubility apparatus. Cordeiro et al. [3] performed the VL isotherm measurements for the methane + n-dotriacontane system at 70 °C (343 K) and pressures up to 70 atm (7.09 MPa).

Chappelow and Prausnitz [4] reported the low-pressure solubilities of methane, ethane, propane, n-butane, isobutane, and hydrogen in n-hexadecane, n-eicosane, squalane, bicyclohexyl, octamethylcyclotetrasiloxane, diphenylmethane, and 1-methylnaphthalene over the temperature range 25–200 °C (298–473 K).

D’Avila et al. [5] reported vapor-phase solubilities of n-decane, 2,2,5- trimethylhexane, tert-butylbenzene, and n-dodecane in compressed methane and compressed nitrogen in the range 30–100 atm (3.04–10.13 MPa) and 25–125 °C (298–398 K). Kaul and Prausnitz [6] also measured the solubilities of heavy hydrocarbons in compressed gases, methane, ethane, and ethylene, at temperatures 50–170 °C (323–443 K) for hexadecane, bicyclohexyl, diphenylmethane, and 1-methyl naphthalene, and in the region 165–272 °C (438–545 K) for eicosane and squalane. Measurements were made in the pressure region 9–80 atm (0.91–8.11 MPa).

Lin et al. [7] presented experimental results for gas–liquid phase equilibria in binary mixtures of n-hexadecane with methane at four temperatures from 190 to 430 °C (463 to 703 K) and pressures from 20 to 250 atm (2.03 to 25.33 MPa). Glaser et al. [8] performed the experimental measurements for several kinds of two-phase boundary in methane + n-hexadecane binary systems in the temperature region from about 285 up to 360 K and pressures up to 85 MPa.

Huang et al. [9], [10] have measured the solubility of carbon dioxide, methane, ethane in n-octacosane and n-eicosane at temperatures up to 300 °C (573 K) and pressures to 50 atm (5.07 MPa). de Leeuw et al. [11] measured VLE of the binary systems nitrogen + tetradecane, methane + tetradecane, and butane + tetradecane at 320–440 K. Rijkers et al. [12] reported experimental measurements on the solubility of hexadecane in methane at temperatures between 285 and 315 K and at pressures up to 25 MPa.

van der Kooi et al. [13] reported the experimental results for the various phase equilibria of methane + eicosane at temperatures varied between 303 K and 370 K and pressures up to 100 MPa. Flöter et al. [14] have measured the experimental vapor–liquid, solid–fluid, and solid–liquid–vapor equilibrium data of the binary system (methane + tetracosane) in the temperature range 315–450 K and for pressures up to 200 MPa. In a subsequent study, Flöter et al. [15] reported the experimental results on vapor–liquid and solid–fluid phase equilibria for three types of ternary mixtures, methane + water + hexadecane, ethane + propane + tetracosane, and methane + docosane + tetracosane at temperatures up to 350 K and at pressures up to 200 MPa.

Machado and de Loos [16] measured the experimental vapor–liquid and solid–fluid equilibrium data for the system methane + triacontane over the temperature range of 315–450 K, and pressures up to 200 MPa. In subsequent study, Machado and de Loos [17] experimentally determined bubble-point curves, dew-point curves, and solid + fluid/fluid boundary curves of methane + tetracosane + triacontane in the temperature range 320–475 K and at pressures up to 200 MPa.

Recently, Campos et al. [18] conducted the experimental measurement of methane solubility in water and hexadecane at temperature range from 303.2 to 323.2 K and a low pressure range from 60.8 to 638.5 kPa. Although only a few data [11] for vapor–liquid equilibrium of binary systems of methane + n-tetradecane has been reported, there is also a lack of experimental data for density and viscosity of saturated liquid phase. We have already reported the binary pair ethane + n-tetradecane [19], ethane + n-octadecane [20], methane + n-octadecane [21], and in the current text, the experimental results of the VLE properties for binary system of methane + n-tetradecane were measured. The solubility, density, and viscosity of methane-saturated n-tetradecane were reported at four temperatures 295, 324, 373, and 448 K and pressures up to 10 MPa. Finally, the phase compositions and densities were modeled using Peng–Robinson (PR) and Soave–Redlich–Kwong (SRK) equations of state.

Section snippets

Apparatus

In previous studies [19], [20], [21], a designed PVT apparatus for gas solubility measurement was described in detail. In the present work, this equipment was used for the measurements, where Fig. 1 represents its schematic diagram. The apparatus consists of two feeding cells, an equilibration cell, four sampling cells, a density measuring cell, a viscometer and two Quizix automated pressure activated pumps.

The equilibration and sampling cells, density measuring cell, and viscometer are placed

Results and discussion

Isothermal VLE data for the methane + n-tetradecane system were measured at T = 294.7, 324.1, 373.4, and 447.6 K, and are presented in Table 2. Experiments were performed for six different pressures from 2 to 10 MPa. The saturated liquid density and viscosity were also measured and summarized in Table 2. The uncertainty of the measurements for compositions was 0.001. The equilibrium gases for all experiments were virtually pure methane due to low volatility of n-tetradecane and the n-tetradecane

Conclusion

The experimental VLE data, composition and saturated liquid density and viscosity for binary system of methane + n-tetradecane were measured at four different temperatures. Measurements were performed using a designed PVT apparatus. The experimental data obtained were modeled using the PR and SRK equations of state. Two different approaches, universal binary interaction parameter and temperature dependent parameter, were considered for the equations of state. The modeling results with the

Acknowledgements

This work was carried out as part of the SHARP (Solvent/Heat-Assisted Recovery Processes) research consortium. The authors wish to express their appreciation for the financial support of all member companies of the SHARP consortium: Alberta Innovates Energy and Environment Solutions, Chevron Energy Technology Co., Computer Modeling Group Limited, ConocoPhillips Canada, Devon Canada Co., Foundation CMG, Husky Energy, Japan Canada Oil Sands Limited, MacKay Operating Co., Nexen Inc., Laricina

References (26)

  • M. Glaser et al.

    J. Chem. Thermodyn.

    (1985)
  • V.V. de Leeuw et al.

    Fluid Phase Equilib.

    (1992)
  • M.P.W.M. Rijkers et al.

    Fluid Phase Equilib.

    (1993)
  • H.J. van der Kooi et al.

    J. Chem. Thermodyn.

    (1995)
  • E. Flöter et al.

    Fluid Phase Equilib.

    (1997)
  • E. Flöter et al.

    Fluid Phase Equilib.

    (1998)
  • J.J.B. Machado et al.

    Fluid Phase Equilib.

    (2004)
  • J.J.B. Machado et al.

    Fluid Phase Equilib.

    (2005)
  • M. Kariznovi et al.

    Fluid Phase Equilib.

    (2012)
  • G. Soave

    Chem. Eng. Sci.

    (1972)
  • A. Peneloux et al.

    Fluid Phase Equilib.

    (1982)
  • S. Ng et al.

    J. Chem. Eng. Data

    (1969)
  • P.M. Cukor et al.

    J. Phys. Chem.

    (1972)
  • Cited by (24)

    View all citing articles on Scopus
    View full text