The Countercurrent Gas Scrubber Genesis of Steady Integral and Differential Mass Balances

Illustration 2,3 The Countercurrent Gas Scrubber Genesis of Steady Integral and Differential Mass Balances 

The packed gas absorber (a), (b) types of mass balances leading to AE (c), (d) types of mass balances leading to ODE. 

These two expressions are processed further by casting them in the following difference form 

We must next formulate an expression for the mass transfer rate N g and here we encounter the same difficulty we had seen in Illustration 2.2 dealing with the reaeration of rivers. In both cases the interfacial area is unknown and we must therefore resort again to the use of a volumetric mass transfer coefficient Kji where the unknown interfacial area a (m /m column volume) is lumped together with If the gas phase is assumed to be controlling, we can write 

Introducing this expression into Equation 2.12a and Equation 2.12b, dividing by AcAz, and letting Az go to zero, we obtain the twin result 

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