Effect of a high-density coarse-particle layer on the stability of a gas-solid fluidized bed for dry coal beneficiation

Coal consumption accounted for 70.48% of the primary energy consumption and coal preparation is used in clean coal technology. Dry separation of a high-density phase fluidized bed has gained widespread attention because of its high precision, stability, and efficiency of separation. The effects of a high-density coarse-particle layer on a gas-solid fluidized bed for coal preparation are necessary. Theoretical analysis of single particle packing structure shows that the pore of a high-density coarse layer has a decisive role in the uniform dispersion of airflow. The porosity rate of a high-density coarse layer is determined mainly by the stack height of particles, followed by the size of the particles in the layer. A mathematical model on bed pressure drop Delta P, height of high-density coarse layer H-CS and fluidizing gas velocity nu was established based on a dense phase gas-solid separation fluidized bed experiment. Density and distribution of coarse-particle layers combined to form high Delta P gas distribution boards, which were important in promoting the stability of the fluidized bed with an increase in H-CS. H-CS had a significant effect on experimental indicators in the actual coal preparation process, followed by the size of the particles in the layer. At optimal experimental conditions, the possible deviation E of the gas-solid separation fluidized bed for coal preparation with the high-density coarse-particle layer can reach 0.08 g/cm(3). (C) 2014 Elsevier B.V. All rights reserved.