The Fluid Bed with Astaritas Uniform Kinetics

We have seen that this model of the bubbling bed is essentially the same as a stirred tank when the two sources of the feed are recognized. These are the fraction (1 - /3) that comes with the gas feed at the bottom of the bed and the fraction /3 in the bubbles which feeds the reactor at all levels and from a diminishing concentration difference. The latter, when referred to the inlet difference c0 - cp, delivers a fraction 1 - exp(- Tr). Thus the total feed minus outlet is (1 - j8) + 3(1 - exp(- Tr)) (c0 — cp) = 1 - /3 exp(-7r) (c0 — cp) and this is what is equated to the reaction rate, (kH0IU)cp. 

On this view of the reactor it is not surprising to find Astarita and Occone s methods for uniform kinetics work for the bubbling fluid bed. Replacing kcp by kcp x, t) F[/ K(y)cp(y)dy]. Thus the balance over the dense phase is 

This leads to the remarkably simple result that the performance of the bed is given be exactly the same function as before, equation (23), save only that Da is further modified by the factor 8. 

A good example is afforded by Langmuir kinetics of a continuous mixture, 

FIGURE 3 Rescaled output as a function of the modified DamkOhler number n = I, 2, 3,4, 5, 10  

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