Page 76 - Packed bed columns for absorption, desorption, rectification and direct heat transfer

71

H dX
= Xe-X; (253)
Bo L dh

at h=H:
dX
= 0, (254)
dh

H dX
= Y-Y. (255)
Bo G dh

X e and Y e are the initial concentrations of the absorbed component in the liquid
and in the gas phase respectively in kmol/kmol;
2
1
G m and L m molar velocities of the gas and liquid phase in kmol. m" . s" ;
w H
Bo G = ;— Bodenstein number for the gas phase;
e(l-H d).D G
T ff
Bo L = r - Bodenstein number for the liquid phase;
3
3
e - free volume of the packing- m /m ;
D G and D L - axial mixing coefficients for the gas and for the liquid phases in
2
m /s;
Because the axial mixing coefficients are depending on the packing
dimensions, they are determined in the dimensionless equations as Peclet
numbers defined for the two phases by:

Peclet number for the gas phase:

p e = ^-^ (256)

E(l-H d).D G

Peclet number for the liquid phase:

Ld n J> L
H d
(257)