Effect of Inlet Flow Strategies on the Dynamics of Pulsed Fluidized Bed of Nanopowder

Abstract

The use of fluidization assistance can greatly enhance the fluidization hydrodynamics of powders that exhibit poor fluidization behavior. Compared to other assistance techniques, pulsed flow assistance is a promising technique for improving conventional fluidization because of its energy efficiency and ease of process implementation. However, the inlet flow configuration of pulsed flow can significantly affect the bed hydrodynamics. In this study, the conventional single drainage (SD) flow strategy was modified to purge the primary flow during the non-flow period of the pulse to eliminate pressure buildup in the inlet flow line while providing a second drainage path to the residual gas. The bed dynamics for both cases, namely, single drainage (SD) and modified double drainage (MDD), were carefully monitored by recording the overall and local pressure drop transients in different bed regions at two widely different pulsation frequencies of 0.05 and 0.25 Hz. The MDD strategy led to substantially faster bed dynamics and greater frictional pressure drop in lower bed regions with significantly mitigated segregation behavior. The spectral analysis of the local and global pressure transient data in the frequency domain revealed a pronounced difference between the two flow strategies. The application of the MDD inlet flow strategy eliminated the disturbances from the pulsed fluidized bed irrespective of the pulsation frequency.

Flow Behavior of Nanoparticle Agglomerates in a Fluidized Bed Simulated with Porous-Structure-Based Drag Laws

“…Fluidization is an attractive method to process quantities of nanoparticles because of the large gas–solid contact area and its potential scalability [ 8 , 9 ]. Peculiarly, nanoparticles do not fluidize individually but form agglomerates as a result of strong inter-particle forces [ 10 ]. The design and scale-up of fluidized beds require understanding of the group flow behavior of the nanoparticle agglomerates.…”

Development of Functional Nanomaterials for Applications in Chemical Engineering

“…Nanomaterials can also be engineered into the industrial production so as to improve the production process, elevate production efficiency, and optimize product performance. The work by Ali and coworkers [ 15 ] studied the effect of inlet flow strategies on the dynamics of pulsed fluidized bed of nanopowder. They changed the conventional single-drainage (SD) flow strategy to the modified double-drainage (MDD) flow strategy, which improved the production process by purging the primary flow during the non-flow period of the pulse to eliminate pressure buildup in the inlet flow line while providing a second drainage path to the residual gas.…”