Solids Flow in Presence of Bed Internals

A very complex solids flow pattern will result when solid obstacles exist in the fluidized bed. The solids recirculation pattern in a cylindrical bed with a single sphere was presented by Lin, Chen, and Chao (1985), and in a 2-D bed with a single and multiple cylinders by Ai (1991). It was demonstrated that large obstacles would not only affect the local solids velocity, but also the global solids circulation patterns. 

A comprehensive study of the effects of internal rod bundles on bed hydrodynamics was compiled (Chen, Chao, and Liljegren, 1983). It was found that, qualitatively, the flow pattern of the solids in the bed was not significantly affected by the presence of distributed tube banks. 

FIGURE 9.11 Effect of internal rod bundles on the magnitude of solids velocity 

Quantitatively, however, the magnitudes of the solids circulation velocity was significantly reduced. A sample result is shown in Fig. 9.11. 

---