(212c) Study of Distribution and Stability of Solid Particles in a Spouted Bed

Gas-solid spouted beds are either cylindrical bed with cone base or the whole bed is in a cone shape where the gas enters as a jet.  The gas forms a spout region that carries the solids upward in a diluted phase that forms a fountain at the top of the bed where the solids fall down and move downward in the annular region.The present work is a part of the scale-up methodology. Steady-state measurements were carried out to study the solid particle's behaviors in the 60^°conical shape spout-air bed with the diameter of 3 inches and height of 36 inches. Radial concentration distributions of particles (glass and steel beads) at various elevations of the bed under different flow patterns were measured using sophisticated optical probes and high accuracy pressure transducers. The superficial air velocity and particles' densities were selected as the effective variables on the particles' distribution and stability into the spouted bed.The hydrodynamic parameters of the process are a difficulty to be measured at the unstable conditions. A stable bed is obtained when the beads can fluidize homogenously.The stable spouting is distinguished by the formation of the stable fountain. Unstable spouting is characterized by swirling and pulsation of the spout.The homogeneity and stability of solid particles appeared  at the  annular region within the position of 5.5 inches above the conical base. The results showed that decreasing in superficial air velocity could promote the solids' concentration, uniformity  and stability at  the annular region . In addition, it has been found that high beads' concentration and stable flow regime can be obtained with high-density particles.The uniformity and stability of solids' particles will enhance the heat and mass transfer into the spouted bed.

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