GE PM880 - Page 223

Application of the Hygrometer (900-901D1) A-41
4/9/98
B. Laboratory Procedures
If in-line measurements are not practical, then there are two
possible laboratory procedures:
1. The unique ability of the GE Panametrics sensor to determine
the moisture content of a liquid can be used as follows:
a. Using the apparatus shown in Figure A-3, dissolve a
known amount of the solids sample in a suitable
hydrocarbon liquid.
b. The measured increase in the moisture content of the
hydrocarbon liquid can then be used to calculate the
moisture content of the sample.
For best results, the hydrocarbon liquid used above should be
pre-dried to a moisture content that is insignificant compared
to the moisture content of the sample.
Note: Since the addition of the solid may significantly change
the saturation value for the solvent, published values
should not be used. Instead, an empirical calibration, as
discussed in the previous section, should be used.
A dew point of -110°C, which can correspond to a moisture
content of 10
-6
PPM
W
or less, represents the lower limit of
sensor sensitivity. The maximum measurable moisture content
depends to a great extent on the liquid itself. Generally, the
sensor becomes insensitive to moisture contents in excess of
1% by weight.