GE Moisture Image 1 Series Service Manual page 85

Application of the Hygrometer (900-901D1)
Henry's Law Type Analysis (cont.)
Also, the value of K is determined from the known water saturation
concentration of the organic liquid at the measurement temperature:
K =
For a mixture of organic liquids, an average saturation value can be
calculated from the weight fractions and saturation values of the pure
components as follows:
Ave. C
where, X is the weight fraction of the i
i
saturation concentration (PPM
total number of components.
In conclusion, the Henry's Law constant (K) is a constant of
proportionality between the saturation concentration (C
saturation vapor pressure (P
temperature. In the General Case, the Henry's Law constant varies
with the measurement temperature, but there is a Special Case in
which the Henry's Law constant does not vary appreciably with the
measurement temperature. This special case applies to saturated,
straight-chain hydrocarbons such as pentane, hexane, heptane, etc.
A: General Case
Determination of Moisture Content if C
The nomograph for liquids in Figure A-2 on page A-32 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
Saturation PPM
W
------------------------------------------- -
P
S
n
∑
( )
= X C
S i S
i
i = 1
th
component, (C
th
) of the i component, and n is the
W
) of water, at the measurement
S
is Known:
S
June 2003
(b)
(c)
) is the
S i
) and the
S
A-23