Coal Separation Intensification and Bed Density Computational Model By Using a Binary Mixture Dense Media Gas Solid Fluidized Bed

Abstract: The binary dense media fluidized bed separator was used to realize the separation intensification of the coal. The mixture of the magnetite powder and the fine coal with the mean diameter of 187.5μm and 750μm for different fine coal weight proportion of 0%, 4%, 8%, 12%, 16%, 20% was used as dense media for fluidization and separation experiments. The computational model between the incipient fluidized velocity U_mf and the weight proportion of the fine coal x_cwas achieved. The bed density computational model in the binary dense media gas-solid fluidized bed was derived based on the two-phase fluidization theory with experimental verification. The stability of bed density in the binary dense media gas-solid fluidized bed was also studied: the optimal gas velocities were almost the 1.3 or 1.4 times of the incipient fluidization velocities for different fine coal weight proportions with the corresponding bed densities of 2.21, 1.97, 1.85, 1.78, 1.66 and 1.54 g/cm³, respectively. The satisfactory yield and ash content of clean coal and the optimum probable error E_p value of 0.065 or 0.07 g/cm³ was achieved when the weight proportion of the fine coal less than 16%, which indicated the separation performance is notably intensified by using the binary dense media fluidized bed.