Page 10 - Packed bed columns for absorption, desorption, rectification and direct heat transfer

concentration of the same component corresponding to its concentration in the
bulk of the liquid;
3
3
AC L in kg/m (or kmol/m ) and AX in mol/mol - driving force of the mass
transfer process calculated as a difference between the concentration of the
transferred component in the bulk of the liquid phase and the equilibrium
concentration of the same component corresponding to its concentration in the
bulk of the gas;
.KG and Ky- overall mass transfer coefficients, when calculating the driving force
2
with the concentration in the gas phase in m/s and mol/(m s) respectively;
Ki and Kjr overall mass transfer coefficients, when calculating the driving force
2
with the concentration in the liquid phase in m/s and in mol/(m s) respectively;
2
F- interfacial mass transfer area, m 9 calculated by the equation;

(8)

3
V p is the volume of the packing in m .
The methods for calculating the overall mass transfer coefficients and
the driving forces are considered below. The products

K Ga = K G.a e, (9)

K Ya = K Y.a e, (10)

respectively

K La = K Lja 9, (11)

K xa = K x.a e, (12)

are called volumetric mass transfer coefficients for the gas (vapour), and for the
liquid phase.

1.1,3. Hydrodynamic regimes of packed bed columns
The liquid phase influences the hydrodynamics of the gas phase in two
different ways. The first of them is by the liquid holdup, according to Eq. (5) it
leads to increasing of the gas velocity. The second one is because the pressure