Experimental Investigation of Segregation for Nonspherical Particles in a Fluidized Bed Solids Mixer

Abstract

A binary mixture of particles varying in size, shape, or density tends to segregate in many different flow situations. Removal of segregation is an important goal as it is often detrimental to process efficiency and product quality. The focus of the current work is to see the effect of the shape of particles on segregation in the particular case of a fluidized bed solids' mixer. The present work describes an experimental method to study the evolution of segregation and its dependence on both the shape and size of the particles. The outcome shows a decreasing order of the axial segregation index as follows: cubic > spherical > oblate > prolate > elongated needle. An increase in the angularity of fine particles improves mixing. The particle shape plays a vital role in determining the extent of segregation. Overall, segregation can be reduced using nonspherical particles.

Experimental Study of Mixing of Nonspherical Particles in a Vibrated Packed Bed Mixer

“…It is observed that fine prolate particles show the best mixing. This trend agrees with previous studies in a fluidized bed and vertical vibrated bed. , …”

“…In comparison to oblate particles, prolate particles demonstrate better mixing. This resulting trend for the nonspherical particle has also been observed by Verma et al 34 in a fluidized bed and agrees with this study.…”

“…This trend agrees with previous studies in a fluidized bed and vertical vibrated bed. 34,58 3.5. Effect of Column's Geometry.…”

“…Limited studies have considered nonspherical particles; however, in the last decade, there is an increased focus on the study of nonspherical particles. The shape of particles plays a significant role in the mixing and segregation processes. − For example, by experimental and numerical techniques, Vollmari et al investigated the effect of nonspherical particles (cuboid) on the mixing quality in monodisperse and bidisperse systems. They found that monodisperse plates ( t = 1.34 s) show the fastest mixing to reach a mixing index value of 0.5 compared to cubes ( t = 1.88 s) and elongated cuboids ( t = 2.04 s).…”

Experimental Investigation of Segregation in the Dilute Phase Transport of Nonspherical Particles through a Pneumatic Conveying System

“…This mixture that arrives later is rich in large particles owing to their lower acceleration. A similar trend in segregation is observed due to the particle size ratio differences in other systems, such as a fluidized bed solid-mixer, vibrated packed solid-mixer, and horizontal rotating cylinder. − …”