Measurement of particle size distribution by superficial velocity and pressure drops across liquid-fluidized beds.

Abstract

When a fluidized bed is formed by a superficial velocity the overall height of the fluidized bed may be divided into sections of given height. A measurement of particle size distribution is developed by means of the superficial velocity and the pressure drops across fluidized beds of various heights.The particle mass in a section of fluidized bed and the voidage are directly calculated by the pressure drop across the bed height. The mean diameter of the particles in a fluidized bed is regarded as the equivalent volume diameter, xi, which can be calculated by the superficial velocity, uf, and the voidage function, F (ei), follows : uf=v∞1/F (e1) =v∞2/F (e2) =…=v∞i/F (ei) =…v∞i= (φsxi) 2 (ρp-ρ) g/18μas where φs refers to the particle-shape factor. The shape factors of experimental material can be obtained by the minimum voidage for fluidization.The particle size distributions of crushed silica sand and crushed glass measured by this method were in good agreement with microscopic data and settling balance data.