GE PM880 - Page 213

Application of the Hygrometer (900-901D1) A-31
4/9/98
B: SPECIAL CASE (cont.)
Typical Problems
1. Find the moisture content in benzene, at an ambient
temperature of 30°C, if a dew point of 0°C is measured with
the GE Panametrics hygrometer.
a. From the literature, it is found that C
S
for benzene at a
temperature of 30°C is 870 PPM
W
.
b. Using a straightedge on Figure A-2, connect the 870
PPM
W
saturation concentration with the 30°C ambient
temperature and read the Henry’s Law Constant of 27.4 on
the center scale.
c. Using the straightedge, connect the above K value of 27.4
with the measured dew point of 0°C, and read the correct
moisture content of 125 PPM
W
where the straightedge
crosses the moisture content scale.
2. Find the moisture content in heptane, at an ambient
temperature of 50°C, if a dew point of 3°C is measured with
the GE Panametrics hygrometer.
a. From the literature, it is found that C
S
for heptane at a
temperature of 50°C is 480 PPM
W
.
b. Using a straightedge on Figure A-2, connect the 480
PPM
W
saturation concentration with the 50°C ambient
temperature and read the Henry’s Law Constant of 5.2 on
the center scale.
c. Using the straightedge, connect the above K value of 5.2
with the measured dew point of 3°C, and read the correct
moisture content of 29 PPM
W
where the straightedge
crosses the moisture content scale.