The voidage variation and operation selectin in a recir culating jet-fluidized bed

摘要

A new recirculating jet-fluidized bed (RJFB), composed of bottom jet, draft tube, top separator and surrounding downcomer, was developed for solid coating and drying. The voidage variation and the selection of gas velocity in both draft tube and downcomer are presented firstly in this study. To achieve a stable solid circulation, the minimum transport gas velocity in the draft tube should be taken a value greater than (0.36 approx 0.5)U_t and the maximum aeration gas velocity from the conical distributor must not cause the solid sluggng occurring in the downcomer. These results are very useful to the design and operation of the RJFB.