28
3 Operation
Criteria for determining good analysis quality
● Methane is definitely present.
●
Methane concentration is 1 % vol.
●
Peaks of the gas components present are clearly recognisable.
Criteria for determining the presence of natural gas
● Good analysis quality (see above)
● Ethane is definitely present.
Ethane analyses of insufficient quality
Note:
Never use poor-quality ethane analyses to demonstrate the pres-
ence of natural gas.
Poor-quality ethane analyses can exhibit the following features, for
example:
●
Curve does not contain any clear peaks (smooth concentra-
tion plot)
Reason:
Residual gases from previous analyses have
accumulated.
Corrective
action:
Purge with test gas, for example:
– 1 % vol. CH
4
in synthetic air
OR
– 100 ppm C
2
H
6
with 1 % vol. CH
4
in synthetic air
●
Curve and symbols (
Analysis
) provide contradictory informa
-
tion about gas components
Reason:
Extremely high or low temperatures (optimal
working temperature: 20°C)
