Page 185 - Industrial Ventilation Design Guidebook
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4.3 HEAT AND MASS TRANSFER I 47
Applying mass transfer theory to a component i in the liquid, assuming
good mixing and neglecting atmospheric concentrations, the evaporation mo-
lar rate of a single component can be expressed as
where
k Gj is the mass transfer coefficient
A is the surface area of the liquid
n t is the total moles of liquid
p\ is the saturation vapor pressure of pure component /
Integrating Eq. (4.331) and knowing that « z° is the initial number of moles of
component / yields
where
Equation (4.333) assumes a constant ratio.
The total mass is
The total evaporation mass flow rate is obtained as
Defining
we obtain the following:
where x i is the mole fraction of component i in the liquid phase, and M is the
molecular weight.