investigation of a cold model of internally circulating fluidized bed with draft tube to be used as a two-zone fluidized bed reactor

in this research, a cold model of internally circulating fluidized bed is investigated. the aim is to find the effects of some of the operating parameters on the performance of the reactor. experiments were carried out in a glass column (30 mm i.d. and 25 cm height) with a centrally located draft tube (11 mm i.d. and 5 or 7 cm height). the bed was loaded with white silica particles (dp = 0.15 - 0.25 mm, ?s = 9500 kg/m3, umf = 1.6 cm/s, ?mf =0.61). specified amount of air was supplied separately into two zones. increasing the gas velocity inside the draft tube led to an increase in pressure deference between two zones, and also led to pulling the solid particles into the draft tube. on the other hand, increasing the gas velocity inside the annular zone resulted in an increase in the movement of the particles which in turn increased the circulating rate of the solid particles