Page 92 - Packed bed columns for absorption, desorption, rectification and direct heat transfer

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y- coordinate in m.
z- coordinates in m;
Z(r thickness of the diffusion layer in the gas phase, m;
Zi- thickness of the diffusion layer in the liquid phase, m;

Greek
2
a - partial heat transfer coefficient, W/(m °C);
P
Ofj = — - relative volatility;
P B
3 3
A- driving force of the process, kg/m or mol/m ;
AQ- driving force of the mass transfer process calculated with the
concentrations for the gas phase as a difference between its bulk concentration
and its equilibrium concentration calculated with the bulk concentration in the
3
3
liquid phase, kg/m or kmol/m ;
A L- driving force for the mass transfer process calculated with the
concentrations for liquid phase as a difference between its bulk concentration
and its equilibrium concentration calculated with the bulk concentration in the
3 3
gas phase, kg/m or kmol/m ;
AQ t- driving force for the mass transfer process calculated with the
concentrations for the gas phase as a difference between its bulk concentration
3 3
and its equilibrium concentration at the interface, kg/m or kmol/m ;
A Li- driving force for the mass transfer process calculated with the
concentrations for liquid phase as a difference between its bulk concentration
3
3
and its equilibrium concentration at the interface, kg/m or kmol/m ;
AA - increase of A over the loading point;
3
3
AH d - increase of the liquid holdup over the loading point, m /m ;
At - difference between the gas and the liquid temperatures, °C;
AP- pressure drop, Pa;
AY m - average driving force of the mass transfer process, for the gas phase,
3
3
kg/m or mol/m ;
AY V- difference between the concentration of the gas phase and the
corresponding equilibrium concentration determined for the concentration of the
3
3
liquid phase, kg/m or mol/m .
2
2
3
3
e - packing void fraction, m /m ;equal to the free column cross-section, m /m ;
H - enhancement factor (coefficient of acceleration as a results of chemical
reaction);
1 - thermal conductivity, J/(m.s.°C)