(118a) The Effect of Gas and Particle Properties on the Fluidization State of Apf and Abf Nanopowders

Previous work has shown that an increase in the viscosity of a fluidizing gas can improve the agglomerate fluidization state of micron-sized particles and APF (agglomerate particulate fluidization) nanopowders. Theoretical work has been shown that the viscosity of a fluidizing gas does not greatly affect the size of the fluidized nanoparticle agglomerates; however, positive effects such as larger bed expansion and an increase in the minimum bubbling velocity have been observed when a higher viscosity gas is used.

In this work, we will be show how the gas viscosity can improve the fluidization characteristics of ABF (agglomerate bubbling fluidization) nanopowders, which are typically difficult to fluidize. The effect of gas density, as well as viscosity, will also be studied. In-situ laser imaging and image analysis techniques to determine the average agglomerate size will be improved and bed pressure fluctuations will be studied to determine at which gas velocities the bed is homogeneously fluidized. The setting velocity of these powders will also be measured and compared to the fluidizing gas velocity to determine the regions of homogeneous fluidization.