A review on fluidization of Geldart Group C powders through nanoparticle modulation

Geldart Group C powders with large specific surface area have been applied in a variety of processes. Gas-solid fluidization is a popular technique for processing these particles. However, most Group C particles are not fluidizable due to strong interparticle forces. In recent decades, one effective technique assisting their fluidization has been the addition of small amounts of nanoparticles to reduce their interparticle forces. This paper reviews both theoretical and experimental studies on the gas fluidization of Group C particles, including nanoparticle modulation techniques, surface morphology, and modelling of interparticle forces. More importantly, the fluidization of these coated Group C particles (the so-called Group C⁺ particles) have been comprehensively discussed. New parameters were proposed to analyze the effects of different forces on their fluidization. The performance of fluidized bed reactors using Group C⁺ catalysts is also reviewed, albeit more works are still needed before the extended applications in chemical engineering.