Mass Transfer in Two-Component Binary System

The mass transfer coefficient of two-component system is the basic information necessary for the prediction of mass transfer rate in the process. The calculation of mass transfer for multicomponent system is also based on the mass transfer coefficients of the correspondent binary pairs (see Sect. 4.1.3). 

One of the traditional models for predicting the binary mass transfer coefficient is based on the penetration theory by Higbie [37]. It is used as our starting point. 

Let us consider the case of a wetted wall (falling film) column undergoing gas absorption with the following assumptions  

The component i in gas phase is absorbed by binary liquid absorbent containing components i and j. 

The velocity of falling absorbent is very low, and mass is transferred by molecular diffusion. The absorption rate is low so as to keep the density of absorbent remains unchanged. 

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