Page 225 - Packed bed columns for absorption, desorption, rectification and direct heat transfer

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3 2
m /(m h). Similar is the situation in Fig, 20 for IMTP. Maybe the difference in
the results is because the comparison for the different Nutter packings is made
at different hydrodynamic regimes, under the loading point for the bigger, and
over the loading point for the smaller packings. Unfortunately, the data for the
gas velocity necessary to solve the problem are not given in [214],

5
B
i
: ,. ,-,.4—i.i
&» I *
1 : i
• NR#
130 1 *
• NR# 75
120 •i - •
dNRft
110
100 J - 1 s |
0 2 4 0 8 10 12 14 10 18 20 22 24
2
Pressum Dmp x10~ , Pa/m
Fig. 28. Influence of the pressure drop on the effective interfacial area. The lines are calculated
according to Eq. (1 IS).

Almost all researchers investigating the effective area of packings have
made their experiments at atmospheric pressure, assuming that under the
loading point the hydrodynamics of the gas phase does not affect the motion of
the liquid. This assumption can be considered as an axiom because under this
point there are no significant forces connected with the gas phase acting on the
liquid, respectively on its distribution over the packing area. That means, if an
effect of the gas phase, respectively of its pressure, on the effective surface area
under the loading point is experimentally proved, it must be looked for different
effects of the pressure which can be detected as changing of the effective area.
That is why the results of Benadda et al [294] that the pressure increasing from