Speeds of sound in {(1 − x)CH 4 + xN 2} with x = (0.10001, 0.19999, and 0.5422) at temperatures between 170 K and 400 K and pressures up to 30 MPa

• Published in: The Journal of chemical thermodynamics 2006-07, Vol.38 (7), p.929-937
• Main Authors: Estela-Uribe, J.F., Trusler, J.P.M., Chamorro, C.R., Segovia, J.J., Martín, M.C., Villamañán, M.A.
• Format: Article
• Language: English
• Subjects: Applied sciences; Crude oil, natural gas and petroleum products; Dispersion; Energy; Equation of state; Exact sciences and technology; Fuels; Gas mixture; Methane; Natural gas; Nitrogen; Prospecting and production of crude oil, natural gas, oil shales and tar sands; Relaxation; Speed of sound
• ISSN: 0021-9614; 1096-3626
• DOI: 10.1016/j.jct.2005.10.006

The speed of sound in {(1 − x)CH 4 + xN 2} has been measured with a spherical acoustic resonator. Two mixtures with x = (0.10001 and 0.19999) were studied along isotherms at temperatures between 220 K and 400 K with pressures up to 20 MPa; a few additional measurements at p = (25 and 30) MPa are also reported. A third mixture with x = 0.5422 was studied along pseudo-isochores at amount-of-substance densities between 0.2 mol · dm −3 and 5 mol · dm −3. Corrections for molecular vibrational relaxation are discussed in detail and relaxation times are reported. The overall uncertainty of the measured speeds of sound is estimated to be not worse than ±0.02%, except for those measurements in the mixture with x = 0.5422 that lie along the pseduo-isochore at the highest amount-of-substance density. The results have been compared with the predictions of several equations of state used for natural gas systems.