Application of the Moving Bed

In moving-bed transport, solid particles are in contiguous contact with one another and are pushed along by the transporting fluid more or less in plug flow, with a voidage equivalent to that of the loosest fixed bed. The velocity of solids movement can be varied from zero to any practical upper limit. 

This type of solids transport came into vogue during the 1950s, when bead-type catalyst was used in petroleum processing (Berg, 1951,1952,1953,1954, 

1956 Weber, 1952), though the mechanism of the related particle-fluid motion was not amply studied until much later (Kwauk, 1963c Sandy et al, 1970 Aoki et al, 1973 Kano et al., 1981). More basic investigations of such particulate systems were provided by Delaplaine (1956). 

From the preceding discussion, it is evident that the uptransport tube needs to be contoured to realize metastable operation of critical transport in order to insure equal lift of all the solid particles. 

The general equation of motion for a thin slice of thickness dz for a moving bed, shown schematically in Fig. 29, can be written as 

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