Pulsed Fluidization of Nanosilica: Rigorous Evaluation of the Efficacy of Pulsation Frequency

Journal Article

2022

Published in: https://doi.org/10.3390/nano12132158

Assisted fluidization techniques can significantly improve the hydrodynamics of difficultto-
fluidize solids. Among these techniques, the pulsed flow strategy is highly promising owing to its
cost-effectiveness and amenability to implementation for large-scale processing. Using commercial-grade,
highly porous nanosilica that shows strong agglomeration behavior, we implemented the
pulsed flow with square-wave pulsation schemes of 0.05, 0.10, and 0.25 Hz frequencies, and compared
their effectiveness in each case. Besides the conventional approach of assessing their efficacy using
the pressure drop data, we have proposed a new approach in this work that consists of computing
the power of the overall pressure drop transient signals. Using the theoretical value, i.e., the effective
bed weight per unit area as a reference, the percentage increase in the power was 27 4, 71 5, and
128 4, respectively, for 0.05, 0.10, and 0.25 Hz pulsation frequencies. In fact, the average pressure
drop values were substantially higher when the partial bed collapse occurred between successive
pulsations when compared with the case of low-frequency pulsations. The pulsation frequency
also affected the evolution of local bed dynamics in various bed regions during the expansion and
collapse of the bed. Moreover, the local and global pressure transients have shown interesting mutual
correlations which were otherwise not evident from their individual transient profiles.

• Volume Number: 12
• Magazine \ Newspaper: nanomaterials
• Pages: 1 to 29