APPLICATIONS OF THE FLUIDISED SOLIDS TECHNIQUE

The use of the fluidised solids technique was developed mainly by the petroleum and chemical industries, for processes where the very high heat transfer coefficients and the 

More recent tests have shown that much of the cracking takes place in the transfer line in which the regenerated catalyst is conveyed into the reactor in the stream of oil vapour. The chemical reaction involved is very fast, and the performance of the reactor is not sensitive to the hydrodynamic conditions. 

Fluidised catalysts are also used in the synthesis of high-grade fuels from mixtures of carbon monoxide and hydrogen, obtained either by coal carbonisation or by partial oxidation of methane. An important application in the chemical industry is the oxidation of naphthalene to phthalic anhydride, as discussed by Riley(131). The kinetics of this reaction are much slower than those of catalytic cracking, and considerable difficulties have been experienced in correctly designing the system. 

Purely physical operations are also frequently carried out in fluidised beds. Thus, fluidised bed dryers, discussed in Chapter 16, are successfully used, frequently for heat-sensitive materials which must not be subjected to elevated temperatures for prolonged periods. 

The design of a fluidised bed for the carrying out of an exothermic reaction involving a long reaction time has been considered by Rowe(132) and, as an example, the reaction 

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