Mixing behavior of binary and multi-component mixtures of particles in waste fluidized beds

A transparent waste fluidized bed cold model (cross section of 0.2 m × 0.2 m and height of 2.0 m) was established. 9 kinds of non-spherical particles (NSP) were selected to represent municipal solid wastes, and silica sand was used as fluidization medium (FM). Binary-component (FM and single kind of NSP) and multi-components (FM and two/or more kinds of NSP) particulate systems were formed. Mixing behaviors in these systems were described by a self-defined mixing index M, and assisted with flow patterns. The effects of fluidization number N defined as the ratio between the gas superficial velocity to the minimum fluidization velocity, properties of NSP such as density, shape and size, and mixing time on the mixing behaviors were experimentally studied. It is found that a dynamic stabilization of mixing could be achieved when the fluidization number N > 1 and the mixing time t > 12 s. The density of NSP has a more significant influence on the mixing behavior than particle size and shape. In a multi-components particulate system, well mixing could be found when the density of NSP gets close to that of fluidization medium.