Computational investigation of hydrodynamics in a turbulent fluidized bed of FCC particles

The hydrodynamics in a high and narrow turbulent fluidized bed of FCC particles is investigated by using computational fluid dynamics (CFD) method. The axial bed density, particle volume fraction and particle velocity in the fluidized bed are predicted and compared with the experiments. The results indicate that there exist two different coexisting regions in the bed: a bottom dense and an upper dilute region. As increasing superficial gas velocity, bed density decreases in the dense phase whilst increases in the dilute phase. In this high and narrow turbulent fluidized bed, however, the bed density decreases sharply even in the dense phase because of the wall restriction. The hydrodynamics resembles slug flow at the initial fluidization stage; as a steady fluidization is achieved, the fluidized bed produces larger bubbles than the conventional one.