非磁性纳米SiO2颗粒在磁场流化床中的流态化

研究了非磁性纳米SiO2颗粒在添加磁性大颗粒磁场流化床中的流化性能。磁性大颗粒的添加量在20%～60%(wt)之间,磁感应强度的大小分别为0.0477、0.0596、0.0715 T。实验中通过测定床层膨胀曲线、床层压降曲线,详细地考察了磁性大颗粒的添加量、磁感应强度及气速的大小对纳米SiO2颗粒流化性能的影响。结果表明:把磁场能引入普通流化床中之后,加入的磁性粗颗粒能够有效地破碎纳米SiO2床层中的活塞、沟流和大聚团,降低最小流化速度,且在最小流化速度时无气泡,使床层膨胀比增加,提高床层的整体流化质量;在流化颗粒相中,磁场能的加入还可以保持床层的稳定性,维持流态化所需的气体体积。

Behavior of Non-Magnetic SiO2 Nano-Particles in a Magnetic Fluidized Bed

The fluidization behavior of SiO2 nano-particles in a magnetic fluidized bed（MFB） by adding coarse magnets was investigated.The amount of coarse magnets was in the range of 20%～60% mass percent.The magnetic-field intensity was 0.0477 T,0.0596 T and 0.0715 T respectively.The influence of the amount of coarse magnets,the magnetic-field intensity and the gas velocity on the fluidization quality of SiO2 nano-particles has been investigated by measuring the bed expansion ratio and pressure drop curves.The results showed that the plug and channel can be broken and the agglomerate size can be decreased by adding coarse magnets.The minimum fluidization velocity was decreased and the bed expansion ratio increased.The fluidization quality of SiO2 nano-particles was improved.In addition,the magnetic field energy can keep the bed stable and maintain sufficient gas to meet the need of fluidization.