Premium
Solid hold‐up measurement in a jet‐impactor assisted fluidized bed using gamma‐ray densitometry
Author(s) -
Nasri Lari Hamed,
Rasouli Majid,
Chaouki Jamal,
Tavares Jason R.
Publication year - 2020
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.16653
Subject(s) - fluidized bed , fluidization , agglomerate , jet (fluid) , mechanics , materials science , range (aeronautics) , work (physics) , momentum (technical analysis) , thermal diffusivity , composite material , physics , thermodynamics , finance , economics
A jet‐impactor assisted‐fluidized bed (JIAFB) for continuous de‐agglomeration of nanopowder agglomerates was presented in previous work. Therein, a jet caused agglomerates to impinge up an impactor, where they would break. However, efficient impactor positioning will be dictated by particle momentum: the product of solid concentration and velocity must be highest. Herein, the variation of solid hold‐up was measured in a fluidized bed of Fe 2 O 3 nanoparticles using gamma‐ray densitometry. Behaviour was compared under minimum fluidization and bubbling regimes, over a wide range of jet velocities (0–200 m s −1 ). A new line‐decomposition approach allowed mapping local solid distribution across seven axial and five radial positions, tangibly demonstrating how increasing the gas velocity enhanced the fluidization quality by increasing axial solid diffusivity. Conversely, increasing jet velocity locally decreased solid hold‐up in the jet‐affected zone, and brought about inhomogeneities. With this information in hand, jet‐to‐impactor distance was optimized and validated experimentally.