Keywords: nanoparticles, vibration assisted fluidisation, silica, nanotechnology, Australia, pressure drop, bed expansion, bed collapse behaviour, agglomerate particulate fluidisation, agglomerate bubbling fluidisation, nanomaterials processing
On the vibration assisted fluidisation of silica nanoparticles
An experimental study was undertaken to investigate the process of vibration-assisted nanoparticle fluidisation. Fluidisation characteristics were assessed by measuring pressure drop, bed expansion and bed collapse behaviour at vibrational intensities between 0 Hz and 34 Hz, for silica nanoparticles with particle densities between 25 kg/m? and 38 kg/m?, and particle sizes of 7 nm and 16 nm. Two modes of nanoparticle fluidisation behaviour were observed: i. agglomerate particulate fluidisation (APF), which is smooth, occurs with extremely high bed expansion, and practically no observable bubbles; ii. agglomerate bubbling fluidisation (ABF) which results in limited bed expansion with large bubbles rising quickly through the bed. The transition between particulate and bubbling modes occurred at different vibrational intensities for each type of particle, however in all cases, smooth agglomerate particulate fluidisation was observed at vibrational frequencies greater than 16.7 Hz. This is much lower than in previous studies of assisted nanoparticle fluidisation, and suggests that vibration assisted fluidisation is a viable technology for the large scale processing (e.g., reacting, dispersing, or coating) of nanomaterials.