Spouting of non‐spherical particles in conical‐cylindrical spouted bed

Abstract

Experiments on the spouting of non-spherical particles in a conical-cylindrical spouted bed, with an inside diameter of 200 mm and a conical base of 60°, were carried out. The minimum spouting status of six kinds of non-spherical particles, the equi-volume sphere diameter ranges from 1.9 to 6.2 mm and the sphericity ranges from 0.73 to 0.95, were tested and compared with two spherical particles. It was found that the changes of minimum spouting velocity with initial bed height and spout gas inlet diameter were similar to the spouting of spherical particles in conventional spouted beds, while decrease in particle sphericity would lead to an increase in the minimum spouting velocity. The tested minimum spouting velocities were well represented by the MathurÀGishler equation of U ms , however a more satisfied prediction could be achieved for non-spherical particles when replacing d p in MathurÀGishler equation with a modified term w À0.5 d v .

Spouting Characteristics of Wet Particles in a Conical-Cylindrical Spouted Bed

“…When the spout diameter increases, the interface between annulus and spout regions will be larger. Consequently, material exchanges between annulus and spout regions will be increased . The degree of air jet dissipation will be increased at this moment.…”

“…Consequently, material exchanges between annulus and spout regions will be increased. 37 The degree of air jet dissipation will be increased at this moment. Accordingly, larger spouting gas flow rate is needed for initial spouting.…”

Spouting behaviors of binary mixtures of cylindroid and spherical particles

“…In a spouted bed handling homogeneous spherical particles, u ms is widely considered to be proportion to [( ρ p − ρ )/ ρ ] n , in which d p and ρ p are the diameter and density of particles and ρ is the density of gas, and m , n are usually greater than 0 . For the binary mixture of cylindroid bamboo particles and glass beads, the increase in X c leads to a increase in mean particle diameter and a decrease in bulk density of the bed, causing the change of u ms .…”

“…The experimental apparatus used in this study includes a cone‐based cylindrical Plexiglas column, a gas supply system, an imaging system, and a multichannel differential pressure signal sampling system, which has been well shown in our previous work . Figure gives the schematic diagram of the experimental setup.…”