Fluidization enhancement of agglomerates of metal oxide nanopowders by microjets

The quality of gas–solid fluidization of agglomerates of nanoparticles has been greatly enhanced by adding a secondary flow in the form of a high‐velocity jet produced by one or more micronozzles pointing vertically downward toward the distributor. The micronozzles produced a jet with sufficient velocity (hundreds of meters per second), turbulence, and shear to break‐up large nanoagglomerates, prevent channeling, curtail bubbling, and promote liquid‐like fluidization. For example, Aerosil R974, an agglomerate particulate fluidization (APF) type nanopowder, expanded up to 50 times its original bed height, and difficult to fluidize agglomerate bubbling fluidization (ABF) type nanopowders, such as Aeroxide TiO2 P25, were converted to APF type behavior, showing large bed expansions and homogeneous fluidization without bubbles. Microjet‐assisted nanofluidization was also found to improve solids motion and prevent powder packing in an internal, is easily scaled‐up, and can mix and blend different species of nanoparticles on the nanoscale. © 2009 American Institute of Chemical Engineers AIChE J, 2010     

Enrichment of iron from bauxite waste in chemical looping combustion

This work reports a method and findings related to the enrichment of iron from bauxite waste (red mud) using chemical looping combustion (CLC). According to the results from X-ray Diffraction, X-ray Fluorescence, and scanning electron microscope–energy-dispersive X-ray spectroscopy, uniformly distributed iron in the red mud particles migrated outward to the surface during the 148 redox cycles in a bubbling fluidized bed reactor, in which the size-reduced iron-oxide particles due to attrition are concentrated in filters. The concentrations of iron oxide in raw particles and attrition fines are 43 wt.% and 83–87 wt.%, respectively. Since the attrition in CLC is inevitable, this recycled iron oxide can be a valuable by-product to compensate for the cost of CLC, whereas the bed materials continue to participate in the CLC process. Moreover, the abundant bauxite waste can be processed in an eco-friendly manner for integrated power generation, carbon capture, and iron recovery by the proposed strategy in this work.     

Electrochemical analysis of charge mediator product composition through transient model and experimental validation

Journal of Applied Electrochemistry - Charge carriers have been studied for use in applications such as fuel cells, redox flow batteries, and electrochemical CO2 reactors for conversion to...