The rotated disc reactor

A rotated disc in a fluid behaves as a pump which draws fluid towards the disc and throws it out radially, Fig. 5.17. Flow to a rotated disc has the surprising property that, under laminar flow conditions, the film thickness is uniform across the whole of the disc surface, excluding edge eifects, and the film thickness (5) is rigorously calculable using fluid mechanics theory [22]. ft is given by Equation 5.12 where D is the diffusion coefficient in cm2 s-1, v is the kinematic viscosity in cm2 s 1 and a is the rotation speed in rad s-1  

This device has been used for many years to measure diffusion coefficients and, more recently, to study the rates of chemical reactions involving solids. In the latter case, a circular pellet of reactant is embedded in the disc. For a dissolving solid which reacts with first-order kinetics (rate constant ki) in the receiving phase (Fig. 5.18) the flux j is given by Equation 5.13 [13]  

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Three phase slurry reactors are characterized by a gas-liquid (K,a) and liquid-solid (k ) mass transfer coefficient. These coefficients were determined for the rotating disc reactor at the appropriate operation conditions ... 

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