Page 305 - Packed bed columns for absorption, desorption, rectification and direct heat transfer

291

1
0.8

0.6 +15% f
45. w
0.01 0.4

to -15%
CD
V
0.2 -

0.1
0.08
8 10 20 40 80100 200

L

Fig. 63. Comparison of the experimental data with the results calculated with Eq. (202).

The calculation of the volumetric mass transfer coefficients using Eq.
(202) for the packing Nr 4 and 5, discussed by Ramm and Chagina [140], shows
that though the specific surface area of the second packing is 1.88 times larger,
their volumetric mass transfer coefficients are practically equal.

3.2.2.1.3 Comparison of the structured packings with vertical smooth walls to
other highly effective types of packings
The most important comparison between different types of packings is
this which gives the possibility to compare them from economical point of
view. Indeed, such comparison is possible only for a given process, with given
prices of equipment and operating costs. Taking into account that the capital
investments are approximately proportional to the packing volume, and that for
a given process the volume of the packing is reverse proportional to the mass
transfer coefficient, the volumetric mass transfer coefficient can be used as a
measure for the capital investments in the mass transfer columns.