Attenuation of Disturbances Using Bed of Nanoparticles

M. Asif, S.S. Ali, A. Ajbar, M. Shahabuddin
King Saud University, SA

Keywords: nanopowder, attenuation, disturbances, pressure drop

Summary:

Ultra-fine powders of hydrophilic nanoparticles of metal oxides, SiO2 for example, exhibit tremendously high porosities, which are as high as 0.98 as compared to 0.40–0.50 normally encountered with beds of micro- or macro-sized solids. While most current large-scale applications of nanoparticles are mainly geared towards utilizing their tremendously high surface area for enhancing surface based rate processes which are often compromised due the agglomeration phenomena, the high porosity aspect of the ultrafine nano-powders however remains unaffected by the agglomeration phenomenon. Since pressure drop is strong function of bed porosity, both in laminar as well as turbulent flow regimes, the existence of high bed porosity ensures extremely low pressure drop. This aspect of the nano-powders coupled with their low minimum fluidization velocity can be effectively utilized for the attenuation of disturbances however strong. While the flow pulsation has proved to be effective in promoting the de-agglomeration nano-powders as the velocity fluctuation when introduced impart their momentum to break the large agglomerates, there is clearly an entirely new dimension to this research that can be used to attenuate strong disturbances or perturbations with the help of bed of nanoparticles.