Fluidization characteristics, solids distributions and gas mixing of a carbonnanotube agglomerate fluidized bed

摘要

A typical nano fiber material, carbon nanotubes (CNTs), was fluidized in a 280mm inner diameter(ID) nano-agglomerate fluidized bed (NAFB). The solids distributions and gas mixing weremeasured by a self-developed conductance method and the hydrogen tracer technique. Typicalnano-agglomerate fluidization characteristics, such as high bed expansion ratio and multi-stagedagglomerate structure, were observed. The fluidization experiment over wide gas velocity rangedemonstrated that both the agglomerate particulate and bubbling fluidizations (APF and ABF) canbe achieved in NAFBs, showing Geldart-A particle characteristics, whereby a systematiccomparison between the fluidizations of CNT agglomerates and Geldart-A particles were carriedout, including transition velocities, solids distributions and gas mixing. The results indicate that theCNT NAFBs have more serious non-uniformity of solids concentration profiles near the wall, butmore homogenous micro flow structures than Geldart-A particles, which leads to a high gas mixingcapacity. These unique hydrodynamics behaviors can be attributed to the difference on themicrostructure between the nano-agglomerates and ordinary particles.