Fluidized solids

For heat transfer directly to solids, predictive equations give directly the volume V or the heat-transfer area A, as determined by heat balance and airflow rate. For devices with gas flow normal to a fluidized-solids bed,... 

Heat Treatment Heat treatment can be divided into two types, treatment of fluidizable solids and treatment of large, usually metallic objects in a fluid bed. The former is generally accomplished in nmlti-compartment units to conserve heat (Fig. 17-27). The heat treatment of large metallic objects is accomplished in long, narrow heated beds. 

This equation has been experimentally verified in liquids, and Figure 2 shows that it applies equally well for fluidized solids, provided that G is taken as the flow rate in excess of minimum fluidization requirements. In most practical fluidized beds, bubbles coalesce or break up after formation, but this equation nevertheless gives a useful starting point estimate of bubble size. 

Effects of current density(I) on the recovery of copper in the reactor can be seen in Fig. 5. As can be seen, the value of R increased gradually with increasing ciurent density, since the mass transfer rate of copper ion is proportional to the current density. Effects of amount of fluidized particles on the recovery of copper can be seen in Fig. 6. Note that the addition of a small amount of fluidized particles (W=1.0wt.%) to the reactor could increase the copper recovery up to 10 25%. It has been mderstood that the contacting of fluidized solid particles with the cathode plate could clean the siuface as well as decrease the diffusion layer of copper ion, which results in the increases of reaction rate and current efficiency, thus, the recovery of copper could be increased. 

Fig. 6. Effects of amount of fluidized solid particles on the recovery of copper in an inverse fluidized bed electrode reactor(LAc=0.015m, Ug= 0.001m/s,UL=0.001m/s).

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