Model Based on Electrostatic Repulsion and Hydrogen Bond Forces To Estimate the Size of Nanoparticle Agglomerates in Fluidization

A comprehensive model was derived based on the balance between drag, collision, and gravity as separation and van der Waals and hydrogen bond as adhesion forces to estimate the equilibrium size of agglomerates formed during the fluidization of nanoparticles. Due to the approximately less than 9% of the total amount of forces, drag and collision forces were not considered in the final model. Also, the influence of using the vapor of different alcohols on the fluidization behavior of hydrophilic silica and alumina nanoparticles was studied by experiments. To justify the improving effect of using alcohols, the electrostatic repulsion force was added to the model for the first time. Methanol and 2-propanol were the most effective alcohols on fluidization improvement, and consequently the smallest size of agglomerates was estimated using physical properties of these two alcohols. The Richardson–Zaki (R-Z) analysis indicated that the fluidization degree of cohesive hydrophilic nanoparticles can be greatly improved by adding polar alcohols to the system. The agglomerate sizes predicted based on R-Z showed a good agreement with the calculated ones by model in the presence of alcohols.