Axial Periodic Structures of the Expansion Process in a Gas-Solid Separation Fluidized Bed

The air dense medium fluidized bed (ADMFB), belongingto the bubblingfluidization regime, plays a critical role in dry coal beneficiation.The separation density of ADMFB depends on the understanding of beddensity. Beyond the uniform hypothesis, a nonuniform hypothesis wasassumed in which the bed density distribution has axial sinusoidalstructures. Based on the force balance model, contact stress is responsiblefor the axial sinusoidal distribution. Experimentally, the fittingresults of the axial sinusoidal distribution during the expansionprocess were presented in which the values of adj. R (2) are from 0.72 to 0.95. Through frequency domain analysis,a low frequency of 0.03 Hz defined as the global horizontal disturbancefrequency is also the reason for the sinusoidal distribution. By analogy,the insect-population model could characterize the particle concentrationmodel perfectly. Finally, the flow structure based on the above analysiswas described to indicate its influence on coal separation.