Page 238 - Packed bed columns for absorption, desorption, rectification and direct heat transfer
P. 238
228
p G - Reynolds number for the gas phase, calculated with nominal
packing size;
m = [0.013-0.088(d p/d c)]Xe u; (119)
d c is the column diameter in m; Read and RBM, the Reynolds numbers for the gas
and for the liquid phase, are calculated using the packing size d p and L,
respectively wg.
The relevance of including the column diameter in equation (119) is
doubtful because the hydrodynamics of the column does not depend on its
diameter. The column diameter could have some influence on m only at great
ratio d/d a but then the equation which takes into account this influence must
have a form which eliminates d c with decreasing of the ratio d/d c.
Sater and Levenspiel [118] offered the equation:
(120)
For calculation of the Peclet numbed for the gas phase in random
packings, Charpentier and Midoux [330] presented the expression:
°
Pe rh= W ph =11.6H'-6.4H t+0.9, (121)
where the packing hydraulic diameter is defined as:
(
'
3
2
« g is the particle specific surface area in m /m .
Linek et al. [331] proposed the equation: