PVT measurements of high pressure gas by the Burnett method

A PVT measurement apparatus by the Burnett method for the temperature range from room temperature to 250 °C and at pressures up to 100 MPa has been developed with a remote operation system. PVT measurements of hydrogen, helium and nitrogen have been accomplished up to 97 MPa. The density uncertainty of the present measurements at 80 °C is estimated to be 0.2 % from the deviations for nitrogen. An existing equation of state (EOS) for hydrogen agrees well with the present measurements within ±0.22 % at 80 °C. The systematic deviations between the EOS and the present measurements at 120 °C and 160 °C are shown with the maximum deviation of 0.52 % at 120 °C and 97 MPa.