An investigation on the thermophysical properties of glycerol

A vibrating tube density meter (VTD) was used to measure density of pure glycerol at different isotherms between 298.16 and 423.12 K, and a pressure range up to 55 MPa. The VTD was calibrated based on the measurements conducted for water and nitrogen. Speed of sound in glycerol was also obtained by mean of a double path acoustic technique in a high pressure acoustic cell. Speed of sound measurements were conducted at five isotherms between 298.14 and 398.16 K with pressures limited to 55 MPa. The acoustic cell was calibrated with distilled water. Validation tests were performed by measuring the density and sound velocity in pure toluene using the VTD and acoustic cell, respectively. The maximum uncertainty (with 95 % level of confidence, k = 2) of the measured densities and sound velocities were found to be 1.27 kg.m−3 and 4.07 m.s−1, respectively.

In addition, the measured sound velocities combined with some reliable literature data for density, heat capacity and sound velocity at atmospheric pressure were utilised to determine density, isobaric, and isochoric heat capacities and the Joule-Thomson coefficient using a numerical integration method. Finally, the calculated densities were compared with measured densities from this work and literature, and a good agreement was observed.