Hydrodynamics of gas–solid fluidized bed of disparately sized binary particles

The hydrodynamics of binary mixture of Geldart Group A and D particles in a turbulent fluidized bed were investigated by experiment and computational fluid dynamics (CFD) method in this paper. The results showed that at low gas velocity, the binary mixtures tend to segregate. At moderate gas velocity, they incline to mix well in the dense phase. Further increasing gas velocity, small particles are entrained and accumulate in the upper regime of the bed, and a segregation trend of the binary mixture appears again. At high gas velocities, segregation efficiency in the continuous classification process increases with increasing the gas velocity and mean residence time of the binary mixture, however, decreases with increasing the small particle content. A strong particle recirculation appears all over the dense phase of the bed, causing an approximately uniform solid composition in radial direction of the fluidized bed.