Modeling for size reduction of agglomerates in nanoparticle fluidization

Nanoparticle fluidization was studied in a centrifugal fluidized bed (CenFB) with variable gravitational acceleration (Gg) conditions. Agglomerate size variation in CenFB nanoparticles (7 nm) was examined with G and fluidization time. With increasing fluidization time, the agglomerate size was found to decrease and reach an equilibrium value after several hours. Higher G reduced agglomerate size. To elucidate these phenomena, a comprehensive model was developed based on the energy balance model with respect to energy consumption for disintegration of agglomerates. Experimental results showed good agreement with the proposed model. Effects of high G on agglomerate fluidization are clarified as follows. The critical minimum size of agglomerates, which is the agglomerate size estimated by the force balance model, is reduced by high G. Attainable energy for disintegration of agglomerates is increased, leading to decreased agglomerate size. © 2004 American Institute of Chemical Engineers AIChE J, 50: 2763–2771, 2004

[1]  Katsuki Kusakabe,et al.  FLUIDIZATION STATE OF ULTRAFINE POWDERS , 1988 .

[2]  Henry Shaw,et al.  Gas–solid fluidization in a centrifugal field , 2001 .

[3]  Hans Rumpf,et al.  Zur Theorie der Zugfestigkeit von Agglomeraten bei Kraftübertragung an Kontaktpunkten , 1970 .

[4]  Jamal Chaouki,et al.  Effect of interparticle forces on the hydrodynamic behaviour of fluidized aerogels , 1985 .

[5]  L. T. Fan,et al.  Incipient fluidization condition for a centrifugal fluidized bed , 1985 .

[6]  Masayuki Horio,et al.  Prediction of agglomerate sizes in bubbling fluidized beds of group C powders , 1998 .

[7]  Hiroyuki Hatano,et al.  Ultrafine particle fluidization and its application to photocatalytic NOx treatment , 2001 .

[8]  Tao Zhou,et al.  Estimation of agglomerate size for cohesive particles during fluidization , 1999 .

[9]  Tao Zhou,et al.  Force balance modelling for agglomerating fluidization of cohesive particles , 2000 .

[10]  Henry Shaw,et al.  Particle mixing in rotating fluidized beds: Inferences about the fluidized state , 1999 .

[11]  L. Fan,et al.  Performance of a rotating fluidized bed , 1984 .

[12]  F. B. Hill,et al.  Dynamics of bubbles and entrained particles in the rotating fluidized bed , 1980 .

[13]  Ye-Mon Chen,et al.  Fundamentals of a centrifugal fluidized bed , 1987 .

[14]  Robert Pfeffer,et al.  On partial fluidization in rotating fluidized beds , 1987 .

[15]  C. Wen,et al.  A generalized method for predicting the minimum fluidization velocity , 1966 .

[16]  C. Y. Wen,et al.  Estimation of bubble diameter in gaseous fluidized beds , 1975 .