Yokogawa GC8000 Process Gas Chromatograph - Manual (Page 488)

<Appendix E Computation Scheme>
App.E-15
IM 11B08A01-01E
The computation formula is:
x
j
=
x
k
x
m
Where:
x
j
: result of ratio computation
x
k
: concentration of peak k
x
m
: concentration of peak m
 Resolution Computation
Resolution computation calculates the peak resolution from the retention time and peak half-
width of two peaks.
The expression formula is:
x
j
=
Where:
x
j
: result of resolution computation
t
r(l)
: retention time of peak l
t
r(m)
: retention time of peak m
t
w(l)
: peak half width of peak l
t
w(m)
: peak half width of peak m
2(t
r(l)
– t
r(m)
)
1.699(t
w(l)
+ t
w(m)
)
 Divisor Computation
When all components, such as a total compensation and area percentage, in the sample are
measured and compensated so that the total is compensated to 100 % of measured values (or a
specifi c value), the trend of changes in the absolute volume of the component concentrations. In
this case, using this computation the trend of changes in the absolute volume can be monitored.
(a) When the standard method (absolute calibration model method) is specifi ed
for computation and the total compensation is enabled.
To perform the Divisor computation, the total compensation should be set to be enabled.
Assuming that the concentrations of each peak by the absolute calibration model are a1, a2,
a3, a4, a5, and a6, that “Total compensation disabled” is set for a2 and a3, and that the total
compensation values is T, the Divisor value is calculated as follows.
Sum = a1 + a2 + a3 + a4 + a5 + a6
Divisor_Value = (Sum - (a2 + a3)) / (T - (a2 + a3))
If (Sum - (a2 + a3)) or (T - (a2 + a3)) is zero, Divisor_Value should be zero.
(b) When the area percentage method is specifi ed for computation.
In the area percentage method, the Divisor value is output in 0 to 1 as taking the standard total
area (set value) as 100 %.
 Function of Calorifi c Value Calculation
As a standard function the GC8000 is capable of calculating calorifi c values. This section
explains how it calculates the value in accordance with the following standards.
• ISO 6976
• ASTM D3588-81
• ASTM D3588-91
• JlS K2301
2nd Edition : May 11, 2012-00
App.E