| dc.description.abstract | Highly accurate density data is required for engineering calculations to make
property estimations in natural gas custody transfer through pipelines. It is also essential
to have accurate pressure-volume-temperature (PVT) data for developing equations of
state (EOS). A highly accurate, high pressure and temperature, compact single sinker
magnetic suspension densimeter has been used for density measurements. First, the
densimeter is calibrated against pure component densities for which very reliable data
are available. After validating its performance, the densities of four light natural gas
mixtures that do not contain components heavier than hexane and two heavy gas
mixtures containing hexane and heavier components having fractions more than 0.2
mole percent were measured. The light mixtures were measured in the temperature range
of 250 to 450 K and in the pressure range of 10 to 150 MPa (1450 to 21,750 psi); the
heavy mixtures were measured in the range of 270 to 340 K and in the pressure range of
3 to 35 MPa (500 to 5,000 psi). Out of those, the data for only four light natural gas
mixtures have been presented in the dissertation due to confidentiality agreements that
are still in force. A force transmission error and uncertainty analysis was carried out. The
total uncertainty was calculated to be 0.11%. Data calculated in this work is compared
with the current industry standard EOS for natural gas systems (AGA8-DC92 EOS) and
GERG EOS, which is the most recently developed EOS for natural gas systems. The
data measured as a part of this research should be used as reference quality data, either to
modify the parameters of AGA8-DC92 EOS and GERG EOS or to develop a more
reliable equation of state with wider ranges of pressure and temperature. | en |
