Estimation of Overall Mass Transfer Coefficients A Simplified Result

5 Estimation of Overall Mass Transfer Coefficients A Simplified Result 

We may use the results of Sections 8.8.3 and 8.8.4 to develop a simple method for estimating overall mass transfer coefficients. The starting point for this development is Eq. 7.3.14 for [Koy] 

For the vapor phase—here assumed ideal—[k ] may be estimated from Eq. 8.3.27 

The matrices [R ] and [R ] have elements defined by Eqs. 8.3.25 using the appropriate mole fractions and ideal mass transfer coefficients of the binary i-j pair kij for the appropriate phase. If we substitute Eqs. 8.8.17 and 8.8.18, together with Eq. 7.3.7 for the linearized equilibrium matrix, into Eq. 7.3.16 we find 

It is interesting to note that the thermodynamic factors cancel out of Eqs. 8.8.19 and 8.8.20. The elimination of the thermodynamic factors will prove particularly useful in the estimation of transfer efficiencies in multicomponent distillation (Section 12.3). 

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