Yokogawa 415 Steam and Gas - Manual (Page 27)

3.2.3 Natural Gas
In the gas industry, compressibility is referred to by a factor, F
PV
, termed the
supercompressibility factor where:
......(10) F
PV
=
Z
B
Z
F
F
PV
is calculated in the flow computer using the NX-19 equation for natural gas
and (F
PV
)
2
is substituted into equations 4 to 8 in place of .
Z
B
Z
F
In order to calculate F
PV
, the following must be programmed within the following
ranges:
Specific Gravity G: 0.554 to 1.000
Carbon Dioxide mol%: 0 to 15%
Nitrogen mol%: 0 to 15%
Also, the temperature and pressure must be within the following ranges:
Temperature -40 to 115°C
(-40 to 240°F)
Pressure 0 to 34,372 kPa
(0 to 5000 psia)
Operation 25