(611e) The Surprising Impact of Particle Properties and Operating Conditions on Gas-Solid Fluidization

In this work, careful attention has been paid to particle characterization and operating conditions used in gas-solid fluidization experiments. For the case of particle characterization, we have developed protocols for the direct measurement of friction, sphericity, and particle roughness, all of which are seen to have a non-negligible and sometimes surprisingly large impact on fluidization measurements.  In particular, a sled device is used to measure friction, sphericity is obtained via optical image analysis, and surface roughness is obtained via processing of AFM surface maps. A combination of experiments and CFD-DEM illustrate the non-negligible sensitivity of each of these quantities on fluidization measurements. Similarly, operating conditions must be carefully controlled to ensure consistent comparison between experiments and simulations of fluidized systems. In particular, the defluidization curve is sensitive to changes in relative humidity down to 10%, and the static friction coefficient is dependent on relative humidity. Collectively, these results point to the need for careful characterization of system parameters and operating conditions in order for high-quality, reproducible data, as is needed for model validation.