Page 141 - Packed bed columns for absorption, desorption, rectification and direct heat transfer

136

From equations (58)-(64) it follows:

a.= K&LZKO/F* ft. (66)

Where from equations (66) and (59 ) it follows:

a e = K Ga.K He.273.16/(P o. fr T. 22.4) (67)

Using data from [63] and [64] the following equation is offered [40]:

Mm a0mf
0J
s
^K He=7.6Jff .(C o^ J(f - ' (68)
From (67) and (68) it follows:

5
0J
'
a e =Kaa. 273.16/(Po TJ2,4x7,6.1(r .(C oli) J(f M87t 0M76 »). (69)
Equation (69) was used [40] for obtaining experimental data for different
0 5 an
random packings. The values of fi, (Con) " d t in equation (69) are calculated
as arithmetical average, based on the initial and end magnitudes of each of
them,

2.1.2.5.9. Method for investigation of the effective surface area at different
properties of the liquid phase
The above discussed methods allow determination of the effective
surface area of the packings for irrigation with water or solution of similar
properties. To study the effect of the liquid phase properties, the following
method is proposed [83].
1. Using the method of Danekwerts, the effective surface area is
obtained.
2. By means of absorption of ammonia in dilute strong acid, or of SO2
in dilute NaOH, the gas film controlled volumetric mass transfer coefficient is
determined.
3. Taking into account that the liquid phase properties for the
experiments in point 1 and 2 are practically the same, from the obtained data it
is possible to calculate the gas-side controlled mass transfer coefficient.
4. Investigations of evaporation of liquid with the necessary viscosity
and surface tension in an air stream. The properties of the chosen liquid insure