Mass Transfer to Suspensions of Small Particles

For a gas-liquid-solid dispersion, such as in fermentation, the same principles hold. However, increased agitation increases the number of gas bubbles and hence the interfacial area. The mass-transfer coefficients from the gas bubble to the liquid and from the liquid to the solid are relatively unaffected. 

Mass tranter to small particles 0.6 mm. Equations to predict mass transfer to small particles in suspension have been developed which cover three size ranges of 

7 Principles of Unsteady-Stale and Convective Mass Transfer 

The following equation has been shown to hold to predict mass-transfer coefficients from small gas bubbles such as oxygen or air to the liquid phase or from the liquid phase to the surface of small catalyst particles, microorganisms, other solids, or liquid drops (B2,C3). 

The first term on the right in Eq. (7.4-1) is the molecular diffusion term, and the second term is that due to free fall or rise of the sphere by gravitational forces. This equation has been experimentally checked for dispersions of low-density solids in agitated dispersions and for small gas bubbles in agitated systems. 

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