GE PM880 - Page 211

Application of the Hygrometer (900-901D1) A-29
4/9/98
A: General Case
Determination of Moisture Content if C
S
is Known:
The nomograph for liquids in Figure A-2 can be used to
determine the moisture content in an organic liquid, if the
following values are known:
• the temperature of the liquid at the time of measurement
• the saturation water concentration at the measurement
temperature
• the dew point, as measured with the GE Panametrics
hygrometer
Complete the following steps to determine the moisture content
from the nomograph:
1. Using a straightedge on the two scales on the right of the
figure, connect the known saturation concentration (PPM
W
)
with the measurement temperature (°C).
2. Read the Henry’s Law constant (K) on the center scale.
3. Using a straightedge, connect above K value with the dew/
frost point, as measured with the GE Panametrics’
hygrometer.
4. Read the moisture content (PPM
W
) where the straight edge
crosses the moisture content scale.
Empirical Determination of K and C
S
If the values of K and C
S
are not known, the GE Panametrics
hygrometer can be used to determine these values. In fact, only
one of the values is required to determine PPM
W
from the
nomograph in Figure A-2. To perform such an analysis, proceed
as follows:
1. Obtain a sample of the test solution with a known water
content; or perform a Karl Fischer titration on a sample of the
test stream to determine the PPM
W
of water.