Page 216 - Packed bed columns for absorption, desorption, rectification and direct heat transfer

206

Without this limitation the same authors presented also the following equation:

(90)

Here the index "w" denotes water.
For calculation of the liquid holdup H tip between the loading and the
flooding points the following equation is presented in [316,322]:

(91)

The comparison of the experimental data with all equations by Billet
and Schultes [316, 322] using the constants presented in Table 6 shows the
following average relative deviations:
for loading and flooding point - 5%;
for liquid holdup- 6.7%;
for pressure drop- 9.1%;
for absorption and desorption mass transfer coefficients controlled by the gas
and the liquid phase -12.4%;
for rectification efficiency - 14.1%.
Because the static holdup of an industrial packing is very low in
comparison to the dynamic one, usually in their calculation the dynamic holdup
is used instead of the total liquid holdup.
For determination of the liquid holdup over the loading point, the
following equation is presented [326]:

(-T
1 + 36 (92)

The comparison of Eq. (92), published in 2001 (after transformation)
and Eq. (88) from 1965 shows that the only difference between them is the
value of the experimental constant, 36, respectively 17. Probably, this is