Page 206 - Packed bed columns for absorption, desorption, rectification and direct heat transfer

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2
where a/ is the surface area of one packing element in m .
For different packings the values of the constants in equation (60) are as
follows:

b p m N

Ceramic Rasehig rings 0.0046 1.21 0.02 0.99
Carbon Rasehig rings 0.0113 1.21 0.02 0.2S
Ceramic Berl Saddles 0.00076 1.56 0.04 0.55

Theoretically the liquid viscosity should not influence the static holdup
because this value is not connected with the motion of the liquid, but only with
the capillary and gravity forces. That is why the obtained results for the value of
m which differs from 0 varying from 0.02 to 0,04 must be considered an
experimental error.
Later, Charpentier et al. [200] presented a correlation with the plot of H s
versus the Eotvos number, defined with the packing size.

Based on the data for Rasehig rings, cylindrical and spherical particles,
Saez and Carbonell [199] proposed an empirical correlation in terms of a
modified EStvos number, Ed*;

H= , (62)
s
20 + 0.9ES*

where

E6* =

Zai-Sha Mao et al. [198] proposed a theoretical model for calculation of
the static holdup of spherical packings using the fundamental principle of
thermodynamics.