Further Properties of the Successive Contact Mechanism

Further Properties of the Successive Contact Mechanism 

The concept of the successive contact mechanism has been given its simplest form by dividing the fluidized catalyst bed into two parts—dense phase and dilute phase. The concept has been found to apply to bed performance, as shown in the preceding section. The reactor model has been developed on the basis of several simplifying assumptions, partly to retain mathematical simplicity as a workable design equation accounting for the relative effects of the variables, and partly due to a relative lack of information about bed performance. Further properties of the mechanism are examined here, particularly as to axial distribution of reactivity inside the bed. 

The dilute phase as defined in Section VII,B,1 partly includes the transition zone. Gas-solid contacting there is much more complicated than is 

Apparently the reaction seems to have almost ended near the distributor this is because the sample has been mostly taken from the emulsion phase. The calculated concentration profile, assuming (eb)sampie = 0.2, is close to the observed profile. However, the axial reactivity distribution inside the bed is not always clear, although this kind of experiment does give useful information. A similar experimental approach has been utilized by other investigators (C7a, F12). 

An alternative to the above method is to introduce one of the reactants at a given vertical bed height and to measure steady-state conversion at the bed outlet by varying the height. This method, named the differential reactivity test, was suggested by T. Kikuchi and applied experimentally to catalytic hydrogenation of ethylene by Furusaki et al. (F18). 

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VIII. Further Properties of the Successive Contact Mechanism. 402... 

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