Intermolecular potential energy surface and thermophysical properties of the CH4–N2 system

Hellmann, Robert; Bich, Eckard; Vogel, E.; Vesovic, Velisa

doi:10.1063/1.4902807

Cited by 51 publications

(145 citation statements)

References 54 publications

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“…However, by adjusting only one dispersion-related parameter for each PES, we were able to achieve excellent agreement with the best experimental data over wide temperature ranges [3,14]. For the CH 4 -CO 2 and CH 4 -H 2 S potentials, we have performed a similar fine tuning by adjusting the C 6 fitting parameter for the site-site interaction between the carbon atoms of CH 4 …”

Section: Analytical Potential Functionsmentioning

confidence: 98%

“…Quantum effects can be taken into account semiclassically by replacing the pair potential V in equation (6) by the QFH effective pair potential [23]. For a molecule pair consisting of a spherical top and a linear molecule, such as the CH 4 -CO 2 molecule pair, the QFH potential can be written as follows [14]:…”

Section: Cross Second Virial Coefficientsmentioning

confidence: 99%

“…In our studies of the CH 4 -CH 4 [3] and CH 4 -N 2 [14] potentials, we also used zero-point vibrationally averaged monomer geometries and applied the highly accurate CCSD(T) method in combination with extrapolation to the CBS limit for the calculation of the interaction energies. However, despite the high level of theory, the calculated values for both the second virial coefficient of pure CH 4 and the CH 4 -N 2 cross second virial coefficient turned out to be systematically too positive in comparison with most of the experimental data.…”

Section: Analytical Potential Functionsmentioning

confidence: 99%

“…Such calculations have been performed for a number of simple gases, such as methane [9,10], carbon dioxide [5], hydrogen sulfide [4,11], water vapor [12,13], or ethylene oxide [6], yielding transport property values with an uncertainty commensurate with the best experimental measurements over wide temperature ranges. We have recently extended the calculations to binary mixtures and have reported values for three traditional transport properties (viscosity, thermal conductivity, binary diffusion coefficient) and for the cross second virial coefficient of (CH 4 + N 2 ) mixtures [8,14]. The objective of this paper is to extend the study to include (CH 4 + CO 2 ), (CH 4 + H 2 S), and (H 2 S + CO 2 ) mixtures.…”

Section: Introductionmentioning

confidence: 99%

“…To account for quantum effects semiclassically, the quadratic Feynman-Hibbs (QFH) effective pair potential [23] was utilized. Transport properties in the dilute gas limit have been determined by means of the classical trajectory approach in conjunction with the kinetic theory of molecular gases [8,14,[24][25][26]. The accuracy and usefulness of this approach has been demonstrated for several pure molecular gases and gas mixtures, see, for example, references [5][6][7][8][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

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Cross second virial coefficients and dilute gas transport properties of the (CH 4 + CO 2 ), (CH 4 + H 2 S), and (H 2 S + CO 2 ) systems from accurate intermolecular potential energy surfaces

Hellmann

Bich

Vesovic

2016

The Journal of Chemical Thermodynamics

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The cross second virial coefficient and the dilute gas shear viscosity, thermal conductivity, and binary diffusion coefficient have been calculated for (CH 4 + CO 2 ), (CH 4 + H 2 S), and (H 2 S + CO 2 ) mixtures in the temperature range from (150 to 1200) K. The cross second virial coefficient was obtained using the Mayer-sampling Monte Carlo approach, while the transport properties were evaluated by means of the classical trajectory method. State-of-the-art intermolecular potential energy surfaces for the like and unlike species interactions were employed in the calculations. All potential energy surfaces are based on highly accurate quantum-chemical ab initio calculations, with the potentials for the unlike interactions reported in this work and those for the like interactions taken from our previous studies of the pure gases. The computed transport property values are in good agreement with the few available experimental data, which are limited to (CH 4 + CO 2 ) mixtures close to room temperature. The lack of reliable data makes the values of the thermophysical properties calculated in this work currently the most accurate estimates for lowdensity (CH 4 + CO 2 ), (CH 4 + H 2 S), and (H 2 S + CO 2 ) mixtures. Tables of recommended values for all investigated thermophysical properties as a function of temperature and composition are provided.

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Section: Analytical Potential Functionsmentioning

confidence: 98%

Section: Cross Second Virial Coefficientsmentioning

confidence: 99%

Section: Analytical Potential Functionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Cross second virial coefficients and dilute gas transport properties of the (CH 4 + CO 2 ), (CH 4 + H 2 S), and (H 2 S + CO 2 ) systems from accurate intermolecular potential energy surfaces

Hellmann

Bich

Vesovic

2016

The Journal of Chemical Thermodynamics

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Precise determination of LJ parameters and Eucken correction factors for a more accurate modeling of transport properties in gases

et al. 2020

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The kinetic gas theory, in particular the equations of Chapman and Enskog, proved to be good and widely applicable approximations for modeling transport properties like diffusion coefficients, viscosities and thermal conductivities. However, these equations rely on at least the Lennard-Jones parameters and for polar gases also the dipole moment. In the scientific literature, the Lennard-Jones parameters are fitted to only one experimentally determined transport coefficient. This approach leads to good agreement between the Chapman Enskog equations employing the so obtained parameters with the experimental data for this specific transport property. However, utilizing the same parameters for modeling different transport properties oftentimes leads to distinct deviations. In this work, it is shown that the subset of Lennard-Jones parameters with which the Chapman Enskog equations can predict the experimental results with deviations comparable to the experimental uncertainty are not identical for each transport property. Hence, fitting towards one property doesn't necessarily yield parameters that are suited to describe the other transport properties. In this publication, the Lennard-Jones parameters and a temperature dependent Eucken correction factor, leading to a significantly higher accuracy than the classical Eucken correction and also its modification by Hirschfelder, are therefore fitted towards all three transport properties simultaneously for seven exemplary gases. This approach leads to a significantly better agreement with experimental data for the three transport properties than the classical approach that relies on fitting to one single transport property and can be utilized to determine accurate sets of Lennard-Jones parameters and Eucken correction factors for any gas species. It provides a computationally inexpensive and practical method for the precise calculation of transport properties over a wide range of temperatures relevant for processes in the chemical industry.

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Determination of the Binary Diffusion Coefficients and Interaction Viscosities of the Systems Carbon Dioxide–Nitrogen and Ethane–Methane in the Dilute Gas Phase from Accurate Experimental Viscosity Data Using the Kinetic Theory of Gases

2023

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The results of viscosity measurements at moderate densities on the two gaseous mixtures carbon dioxide–nitrogen and ethane–methane including the pure gases between 253.15 K and 473.15 K, originally performed by Humberg et al. at Ruhr University Bochum, Germany, using a rotating-cylinder viscometer between 0.1 MPa and 2.0 MPa, were employed to determine the interaction viscosity, $$\eta _{12}^{(0)}$$ η 12 ( 0 ) , and the product of molar density and diffusion coefficient, $$(\rho D_{12})^{(0)}$$ ( ρ D 12 ) ( 0 ) , each in the limit of zero density. The isothermal viscosity data were evaluated by those authors with density series restricted to the second order at most to derive the zero-density viscosities and initial density viscosity coefficients, $$\eta _\textrm{mix}^{(0)}$$ η mix ( 0 ) and $$\eta _\textrm{mix}^{(1)}$$ η mix ( 1 ) , for the mixtures, as well as, $$\eta _i^{(0)}$$ η i ( 0 ) and $$\eta _i^{(1)}$$ η i ( 1 ) ($$i=1,2$$ i = 1 , 2 ), respectively, for the pure gases. Humberg et al. have already compared their $$\eta _\textrm{mix}^{(0)}$$ η mix ( 0 ) and $$\eta _i^{(0)}$$ η i ( 0 ) data for carbon dioxide–nitrogen and ethane–methane with corresponding viscosity values theoretically computed for the nonspherical potentials of the intermolecular interaction. Now we employed $$\eta _\textrm{mix}^{(0)}$$ η mix ( 0 ) and $$\eta _\textrm{mix}^{(1)}$$ η mix ( 1 ) as well as $$\eta _i^{(0)}$$ η i ( 0 ) and $$\eta _i^{(1)}$$ η i ( 1 ) in two procedures to derive $$\eta _{12}^{(0)}$$ η 12 ( 0 ) values. For this, we needed $$A_{12}^*$$ A 12 ∗ values (ratio between effective cross-sections of viscosity and diffusion). But the second procedure applying the initial density viscosity coefficients $$\eta _\textrm{mix}^{(1)}$$ η mix ( 1 ) and $$\eta _i^{(1)}$$ η i ( 1 ) failed to yield reasonable $$\eta _{12}^{(0)}$$ η 12 ( 0 ) values. The first procedure should provide the best results when it is possible to use $$A_{12}^*$$ A 12 ∗ values computed for the nonspherical potential. The effect is comparatively small if $$\eta _{12}^{(0)}$$ η 12 ( 0 ) is determined. But if $$(\rho D_{12})^{(0)}$$ ( ρ D 12 ) ( 0 ) is calculated from $$\eta _{12}^{(0)}$$ η 12 ( 0 ) using $$A_{12}^*$$ A 12 ∗ values for the nonspherical potential, the impact is several percent. Moreover, the experimentally based $$\eta _{12}^{(0)}$$ η 12 ( 0 ) and $$(\rho D_{12})^{(0)}$$ ( ρ D 12 ) ( 0 ) data agree with theoretically calculated values for the nonspherical potentials.

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Intermolecular potential energy surface and thermophysical properties of the CH4–N2 system

Cited by 51 publications

References 54 publications

Cross second virial coefficients and dilute gas transport properties of the (CH 4 + CO 2 ), (CH 4 + H 2 S), and (H 2 S + CO 2 ) systems from accurate intermolecular potential energy surfaces

Cross second virial coefficients and dilute gas transport properties of the (CH 4 + CO 2 ), (CH 4 + H 2 S), and (H 2 S + CO 2 ) systems from accurate intermolecular potential energy surfaces

Precise determination of LJ parameters and Eucken correction factors for a more accurate modeling of transport properties in gases

Determination of the Binary Diffusion Coefficients and Interaction Viscosities of the Systems Carbon Dioxide–Nitrogen and Ethane–Methane in the Dilute Gas Phase from Accurate Experimental Viscosity Data Using the Kinetic Theory of Gases

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