There is a considerable number of published works on density based separation of particles, dating from long ago. I am currently trying to separate char particles produced in a bubbling fluidized bed creating a segregation zone (floating layer of char on top of sand bed). Thus the complexity is that the fluidized bed is a high temperature reactor as well. Would anyone recommend specific readings?
Dear Lydia
In fluidized bed combustion (FBC), the understanding of various phenomena associated with char combustion is very important. In a case of fluidization with cohesive particles, stable channels and cracks are easily formed in the whole bed and the bed fluidity of such cohesive particle is poor. A fluidized bed is formed when a quantity of a solid particulate substance (usually present in a holding vessel) is placed under appropriate conditions to cause a solid/fluid mixture to behave as a fluid.Adding the vibration to the bed is one of the ways for improving the bed fluidity for cohesive particle bed. To examine the separation characteristics of solid materials in the liquid-solid fluidized bed, the motion of one solid material immersed in the fluidized bed was examined. The fluidizing particles were put in the column and fluidized by the liquid flow. To reduce the effects of size and shape of a sample, the liquid velocity was set at a low value, i.e., relatively small particles were used as the fluidizing particles. The glass beads (rho(p) = 2500 kg/m3 whose diameters were 60, 100, 200 and 500 Am and the zirconia beads (rho(p) = 6000 kg/m3 whose diameters were 60 and 100 mu m were used as the fluidizing particles. Tap water was used as the fluidizing liquid. One sample, whose density was adjusted, was immersed in the bed, and the existing height of the sample in the bed was examined for different liquid velocities, fluidizing particle diameters and densities, experimentally. When the liquid velocity is low and the apparent density of the particle bed is higher than that of the sample, the sample floats on the bed (floating region). As the liquid velocity increases, the apparent density of the bed decreases and the sample becomes to suspend in the bed (suspending region). Further increments of liquid velocity makes the sample settles at the bottom of the bed (settling region). As the liquid velocity increases, the apparent density of the particle bed decreases and the sample sinks in turn. The range of the non-dimensional sample existing height in the suspending region is affected by the diameter of the fluidizing particle, but is not affected by the density of the fluidizing particles.
Regards
Prem Baboo
Article Separation of Solid Particles by Density Difference in a Liq...
Thank you very much! I am looking for the proper equations to design some tests now.
Best regards
Lydia
A few valuable book references follow:
Frederick A. Zenz, Donald Frederick Othmer, "Fluidization and Fluid-Particle Systems", Reinhold Chemical Engineering Series, Reinhold Publishing Corp. (New York) / Chapman & Hall Ltd. (London), 1960.
Nicholas P. Cheremisinoff, Paul N. Cheremisinoff, "Hydrodynamics of Gas-Solids Fluidization", Gulf Publishing Co., Houston, 1984.
Wen-Ching Yang, "Handbook of Fluidization and Fluid-Particle Systems", Marcel Dekker Inc., New York and Basel, 2003.
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