Instruction Manual

<Appendix E Computation Scheme>
App.E-18
IM 11B08A01-01E
(b) ASTM D3588-81
The GC8000 converts each peak result obtained in volume percent into the one in mole fraction,
and calculates the real gas calorifi c value, real gas specifi c gravity, compressibility factor, and
Wobbe index of the sample gas from the ideal gas calorifi c value, ideal gas specifi c gravity,
compressibility factor, and compressibility summation factor of each component.
<Formula>
Z = 1 – ( )
2
+ 0.005(2x
H
– x
H
2
)x
i
H
r
: real gas calorific value (total or net)
H:ideal gas calorific value (total or net)
H
i
: ideal gas calorific value of component i (total or net)
G
r
: real gas specific gravity
G:ideal gas specific gravity
G
i
: ideal gas specific gravity of component i
z:compressibility factor
z
i
: compressibility factor of component i
b
i
: compressibility summation factor of component i
x
i
: mole fraction of component i
x
H
: mole fraction of hydrogen
x
Vi
: volume percent of component i
W:Wobbe Index

H
r
=
z
H
G
r
=
z
0.99959G
W =
G
r
H
r
H =
x
i
H
i

G =
x
i
G
i

x
i
=
x
Vi
z
i
x
Vi
z
i

b
i
Where:
2nd Edition : May 11, 2012-00