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Formation of particle agglomerates after switching fluidizing gases
Author(s) -
Kai Takami,
Takahashi Takeshige
Publication year - 1997
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.690430209
Subject(s) - fluidization , agglomerate , emulsion , particle (ecology) , chemistry , diffusion , economies of agglomeration , pressure drop , transient (computer programming) , particle density , chemical engineering , fluidized bed , materials science , thermodynamics , composite material , volume (thermodynamics) , biochemistry , oceanography , physics , organic chemistry , computer science , engineering , geology , operating system
Abstract When a fluidizing gas is switched from a low‐density gas to a high‐density gas, particles in the emulsion phase agglomerate and bubbles disappear. At the same time, channeling occurs and a decrease in the pressure drop over the bed is observed. The disturbance of fluidization is temporary, and normal fluidization is restored after several minutes. The study of mechanisms of the transient phenomena shows that the difference in diffusion rates of the two gases in the emulsion phase caused the agglomeration of particles. Because the mobility of particles was reduced, channels were formed and the fluidizing gas bypassed through them. Effects of the properties of the fluidizing gases and particles on the intensity of the transient phenomena were also studied. The intensity increased with increasing difference in the densities of the two gases. The transient phenomena were considerable for small‐ and light‐particle systems.