Pressure-density-temperature measurements of ethylene

As a contribution to current projects on the thermophysical properties of ethylene for the preparation of reference tables, measured PVT data are presented. For the measurements in the single-phase region, two types of equipment have been employed: an expansion apparatus to determine isotherms and a constant volume apparatus to determine isochores. Both the design and calibration of each type of equipment and the experimental procedures are described. The accuracy of the 251 measured PVT data on 10 isotherms and 16 isochores, which cover the temperature range from –30 to 80C, with pressures up to 250 bar, is about 0.1% in the compressibility factors. The critical temperature was determined with the result t _c =9.22±0.02C by visual observation of the disappearance of the meniscus.