Model Experiment on the Permeability of Gas in the Shaft of a Blast Furnace

Abstract

The pressure drops caused by the flow of gas through the various packed beds were measured in order to obtain some information on the permeability of gas in the shaft of a blast furnace. The packed beds used in this study are (a) A-type bed or a bed packed with single sized materials (glass beads, alumina pellets, Marcona pellets, or coke), (b) B-type bed or a bed packed layer by layer with different sized materials, and (c) C-type bed or a bed composed of binary mixtures of materials with different size distributions. The results obtained are as follows: (1) The pressure drops for A-type bed were correlated by the equation, Δpg_cD²_p∈³/LμU (1-∈) (1-∈) ²=6.8φ_cX^0.8, where X=R_e/ (1-∈), R_e=D_pU_ρ/μ, D_p=diameter of materials, L=length of the bed, U=superficial velocity of gas, gc=conversion factor, ρ=density of gas, μ=viscosity of gas, ∈=fractional voidage, and Δp=pressure drop. (2) The value of φ_c was unity in the range 300<X<8000 for spherical glass beads with smooth surface, which consisted with the value obtained by HICKS under the similar conditions, while the value for another materials was greater than unity. From this, it was satisfactory to consider the coefficient φ_c as the parameter due to the degree of surface roughness and the degree of distortion. (3) The pressure drops for both B-type and C-type beds could be estimated by means of the above equation, in which D_p and φ_c were calculated by the equations W/D_p=ⁿΣ_i=1W_i/D_{p, i}, and W/φ_c=ⁿΣ_i=1W_i/φ_{c, i}, respectively, where W=weight of packing materials and i=number of layers or component of mixtures.