Interfacial area generation

In Eq. (31c), Nxn and N n are the mass transfer rates. These are calculated from multicomponent mass transfer equations. The equations used take into account the mass transfer coefficients and interfacial areas generated in the specific contactor, reaction rates, heat effects, and any interactions among the above processes. 

On the other hand, when the reaction occurs in both bulk and film, the reactor should combine good interfacial area generation with efficient bulk liquid utilization. A measure of the efficiency of bulk liquid utilization is the parameter 7bu given by (Kramers and Westerterp, 1963)... 

Reactor selection tends to be complicated in the range 0.03 < y/M < 0.1 where large values of both interfacial area and liquid holdup are required. This is also true of regime 2, despite its very low value of y/M, because pure mass transfer through the film is the controlling resistance, so that interfacial area generation becomes an important consideration. In all such cases, the minimum volume criterion for reactor selection becomes inadequate, and the choice has to be based only on the minimum energy criterion to be discussed in the next section. 

Reactor type Criterion 2(a) minimum specific energy required to achieve contact, P, (kW/m ) Criterion 2(b) interfacial area generated per unit volume per unit energy input, 12 (m /kWh)... 

So, for laminar contactors we predict that the mass transfer is a much weaker function of the amount of energy dissipated than for turbulent contactors. The fact that energy is not required for interfacial area generation is in perfect agreement with this scaling analysis. Of course, there still is an impact of velocity on... 

The reaction chemistries themselves are typically very fast and irreversible. Thus, the overall reaction kinetics are controlled primarily by the kinetics of interfacial area generation. 

When a fluid is mixed, the interfacial area generally increases and the striation thickness decreases. Spencer and Wiley (6) derived for a surface element with an arbitrary orientation the interfacial area generation after a total shear of y ... 

Table 5.2 Interfacial Area Generation for Different Amounts of Total Shear and a Different Number of Process Steps...

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