Cross second virial coefficients and dilute gas transport properties of the (CH4+CO2), (CH4+H2S), and (H2S+CO2) systems from accurate intermolecular potential energy surfaces

• Published in: The Journal of chemical thermodynamics Vol. 102; pp. 429 - 441
• Main Authors: Hellmann, Robert, Bich, Eckard, Vesovic, Velisa
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-11-2016
• Subjects: Carbon dioxide; Hydrogen sulphide; Methane; Potential energy surface; Second virial coefficient; Transport properties; Potential energy surface; Methane; Hydrogen sulphide; Second virial coefficient; Transport properties; Carbon dioxide
• ISSN: 0021-9614; 1096-3626
• DOI: 10.1016/j.jct.2016.07.034

•Highly accurate intermolecular potential surfaces for the CH4–CO2, CH4–H2S, and H2S–CO2 molecule pairs have been developed.•The cross second virial coefficients for these molecule pairs have been calculated.•Dilute gas viscosities, thermal conductivities, and binary diffusion coefficients of the binary mixtures have been computed.•The calculated values accurately characterize the thermophysical properties of the dilute mixtures at T=(150 to 1200)K.
The cross second virial coefficient and the dilute gas shear viscosity, thermal conductivity, and binary diffusion coefficient have been calculated for (CH4+CO2), (CH4+H2S), and (H2S+CO2) 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 (CH4+CO2) 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 low-density (CH4+CO2), (CH4+H2S), and (H2S+CO2) mixtures. Tables of recommended values for all investigated thermophysical properties as a function of temperature and composition are provided.