The pressure-drop-velocity curve of -0.4+0.3 mm magnetite medium.
In the gas-solid fluidized bed system, the minimum fluidization velocity, Umf, which can be calculated by pressure-dropvelocity
curve, represents the transition between the fully fixed and initial fluidized state. Fluidization of magnetite powder by a
superficial air velocity ranges between 0 and 0.175 m/s with most magnetite powder size ranging from 0.3 to 0.4 mm gives rise to
heterogeneous systems. The static bed height is 120 mm and the pressure drop test is carried out between bed heights of -30+10
mm, -70+50 mm and -110+90 mm. The experimental results are presented in Figure 2. The three solid line with different
symbols in this figure represent the pressure drop test results of different bed heights as a function of superficial air velocity. The
superficial air velocity is divided into A, B and C regions.