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The speed of sound in the normal hydrocarbonsn- C23H48andn- C24H50has been measured up to 150 MPa in the temperature range (293.15 to 373.15) K using a pulse technique operating at 3 MHz. The data have been used to evaluate various thermophysical properties such as density, and isentropic and isothermal compressibilities up to 150 MPa with the help of additional density measurements performed at atmospheric pressure.

The speed of sound in a synthetic and a real distillation cut has been measured up top=150 MPa in the temperature rangeT=(293.15to373.15) K. The synthetic system, which is representative of distillation cuts, is made up of five components with high boiling point temperatures of aboutTb=523 K belonging to essential chemical families found in natural fluids {iso, or n-paraffins, naphthenes, and aromatics (alkybenzene, or alkylnaphtalene)}. The distillation cut comes from the separation of a standard crude oil by distillation aroundT=523 K. The measurements allow the evaluation of various thermophysical properties such as densities, and isentropic and isothermal compressibilities up top=150 MPa with the help of additional density measurements performed at atmospheric pressure.

This paper presents essentially measurements of ultrasonic speeduand phase transition in a ternary mixture made up of methane, propane, and octane, envisaged in the gaseous state. The ultrasonic-speed measurements were carried out in the temperature range from 293.15 K to 373.15 K and at pressures from the phase boundary up to 100 MPa with a total uncertainty of less than 0.1 per cent. Comparisons between the results and the predictions of several equations of state, widely used in the petroleum industry, are reported and discussed.

Thermophysical properties such as speed of sound, density, and isentropic and isothermal compressibilities have been obtained from ultrasonic speed measurements on two synthetic systems which are representative of distillation cuts with high bubble points (T=520 K andT=573 K, respectively). The first system (composition expressed in mass fraction), (0.40C13H28+0.35C13H26+0.25C13H20), was investigated at pressures from (0.1 to 150) MPa in the temperature rangeT=(293.15 to 373.15) K, whereas the second one, (0.40C17H36+0.35C16H32+0.25C16H26), was investigated at pressures up to 100 MPa in the temperature rangeT=(293.15 to 373.15) K.Copyrigt 1998 Academic Press Limited

This paper reports experimental ultrasonic-speed measurements for two gaseous binary mixtures. The first: (0.90CH₄ + 0.10C₃H₈)(g) was investigated at pressures p from 10 MPa to 70 MPa in the temperature domain from 262 K to 400 K. The second: {0.98CH₄ + 0.02CH₃(CH₂)₆CH₃}(g) was investigated from the phase boundary to p = 100 MPa. The ultrasonic speeds obtained were compared with the values calculated from the Lee-Kesler equation of state. Copyright 1994, 1999 Academic Press