Mass Transfer Rates and Effective Interfacial Areas

Mass Transfer Rates and Effective Interfacial Areas 

Liquid-phase mass transfer data [13-15] were correlated by the following dimensionless equation [13]  

The effective interfacial areas for absorption with a chemical reaction [6] in packed columns are the same as those for physical absorption except that absorption is accompanied by rapid, second-order reactions. For absorption with a moderately fast first-order or pseudo first-order reaction, almost the entire interfacial area is effective, because the absorption rates are independent of kL as can be seen from Equation 6.24 for the enhancement factor for such cases. For a new system with an unknown reaction rate constant, an experimental determination of the enhancement factor by using an experimental absorber with a known interfacial area would serve as a guide. 

Ample allowance should be made in practical design calculations, since previously published correlations have been based on data obtained with carefully designed experimental apparatus. 

The absorption of ammonia into water is a typical case where gas-phase resistance controls the mass transfer rates. 

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YOS 58] Yoshida F., Koyanagi T., Liquid phase mass transfer rates and effective interfacial area in packed absorption columns , Ind. and Eng. Chemistry, vol. 50, no. 3, p. 365, 1958. 

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