Aggregation behavior of nanoparticles in fluidized beds

被引:208
作者
Hakim, LF [1 ]
Portman, JL [1 ]
Casper, MD [1 ]
Weimer, AW [1 ]
机构
[1] Univ Colorado, Dept Chem & Biol Engn, Boulder, CO 80309 USA
基金
美国国家科学基金会;
关键词
fluidization; nanoparticles; dynamic aggregation; vibration; interparticle forces; vacuum;
D O I
10.1016/j.powtec.2005.08.019
中图分类号
TQ [化学工业];
学科分类号
0817 ;
摘要
The fluidization behavior of fumed silica, zirconia, and iron oxide nanopowders was studied at atmospheric and reduced pressures. Using a high-speed laser imaging system, the characteristics of fluidized aggregates of nanoparticles were studied in real time. The effect of different particle interactions such as London-van der Waals, liquid bridging and electrostatic on different fluidization parameters was studied at atmospheric pressure. The reduction of interparticle forces resulted in a reduced aggregate size and minimum fluidization velocity (U-mf) and an increased bed expansion. Nanoparticles were also fluidized at reduced pressure (similar to 16 Pa) with vibration to study the effect of low pressure on the minimum fluidization velocity. Aggregate properties (size, density) instead of primary nanoparticle properties were found to govern the minimum fluidization velocity and expansion of the fluidized bed. An important consideration is the relative strength of intra-aggregate interparticle forces (forces within the aggregate holding nanoparticles together) to inter-aggregate interparticle forces (forces between aggregates). This relative strength may be inferred from the sphericity of the aggregates during fluidization. (c) 2005 Elsevier B.V. All rights reserved.
引用
收藏
页码:149 / 160
页数:12
相关论文
共 71 条
[1]   Effects of quenching and annealing on the high-temperature magnetic properties of rapidly quenched Au80Fe20 alloy [J].
Allia, P. ;
Coisson, M. ;
Tiberto, P. ;
Vinai, F. .
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS, 2004, 272 :E1189-E1190
[2]   FLUIDIZATION BEHAVIOR OF PARTICLES UNDER AGGLOMERATING CONDITIONS [J].
ARASTOOPOUR, H ;
HUANG, CS ;
WEIL, SA .
CHEMICAL ENGINEERING SCIENCE, 1988, 43 (11) :3063-3075
[3]   PROPAGATION OF PRESSURE WAVES AND FORCED-OSCILLATIONS IN GAS-SOLID FLUIDIZED-BEDS AND THEIR INFLUENCE ON DIAGNOSTICS OF LOCAL HYDRODYNAMICS [J].
BI, HT ;
GRACE, JR ;
ZHU, J .
POWDER TECHNOLOGY, 1995, 82 (03) :239-253
[4]   EFFECT OF INTERPARTICLE FORCES ON THE HYDRODYNAMIC BEHAVIOR OF FLUIDIZED AEROGELS [J].
CHAOUKI, J ;
CHAVARIE, C ;
KLVANA, D .
POWDER TECHNOLOGY, 1985, 43 (02) :117-125
[5]   TYPES OF GAS FLUIDIZATION [J].
GELDART, D .
POWDER TECHNOLOGY, 1973, 7 (05) :285-292
[6]   Fundamental hydrodynamics related to pressurized fluidized bed combustion [J].
Gogolek, PEG ;
Grace, JR .
PROGRESS IN ENERGY AND COMBUSTION SCIENCE, 1995, 21 (05) :419-451
[7]   The London - Van Der Waals attraction between spherical particles [J].
Hamaker, HC .
PHYSICA, 1937, 4 :1058-1072
[8]   A STUDY ON THE REMOVAL OF FINE PARTICLES BY LIQUID FLUIDIZED-BEDS [J].
HAN, KN ;
SATHYAMOORTHY, R ;
FUERSTENAU, MC .
INTERNATIONAL JOURNAL OF MINERAL PROCESSING, 1990, 29 (3-4) :279-287
[9]   Production and characterization of nanocrystalline SnO2 films on Al2O3 agglomerates by CVD in a fluidized bed [J].
Hua, B ;
Li, CZ .
MATERIALS CHEMISTRY AND PHYSICS, 1999, 59 (02) :130-135
[10]   Problems in PFBC boiler (2): characterization of bed materials found in a commercial PFBC boiler at different load levels [J].
Ishom, F ;
Harada, T ;
Aoyagi, T ;
Sakanishi, K ;
Korai, Y ;
Mochida, I .
FUEL, 2004, 83 (7-8) :1019-1029