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.
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