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Title: Equation of state for natural gas systems
Author: Estela-Uribe, Jorge Francisco
ISNI:       0000 0004 2737 3587
Awarding Body: Imperial College London
Current Institution: Imperial College London
Date of Award: 1999
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The development of an accurate equation of state for natural gas systems and an experimental programme of measurements of the speed of sound in binary gaseous mixtures is presented. Accounts are given of the statistical mechanical foundations of the extended principle of corresponding states, the theory of spherical acoustic resonators, the relationship between the speed of sound and thermodynamic properties and the theory of virial coefficients and intermolecular potential energy functions. Detailed information is presented on the development of two separate extended corresponding states models based on correlations of molecular shape factors over a wide range of reduced temperature and density, with methane as the reference fluid. One of the models constitute a generalised functionality in terms of the critical constants and the acentric factors; the other is a substance-dependent formulation whose parameters are reported for hydrocarbons from methane to w-pentane, nitrogen, carbon monoxide, carbon dioxide and normal hydrogen. Predicted volumetric, vapour-liquid equilibria and caloric properties are presented and compared to up-to-date experimental data. The method by which these models may be extended to multicomponent systems is also presented along with values of parameters in correlations of temperature- and density dependent binary interaction parameters for eighteen binary systems. Calculated compression factors and speeds of sound are presented for binary and natural gas systems and compared to predictions from other models. Compression factors and speeds of sound in natural gas mixtures are calculated on average within ± 0.05 per cent for temperatures between 270 K and 330 K and pressures up to 12 MPa. The technique of the measurement of the speed of sound in gases from the resonance frequencies of an spherical cavity is described. Results of measurements on two binary mixtures of methane with nitrogen and one of methane plus carbon dioxide are reported. These results were utilised to validate the models mentioned above. These speeds of sound are precise within about 15 parts per million. Second and third acoustic virial coefficients were also determined for these mixtures. Parameters of isotropic and site-site Maitland-Smith intermolecular potentials and Axilrod-Teller triple-dipole terms were obtained, from which interaction second and third ordinary virial coefficients are calculated.
Supervisor: Trusler, Martin Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available