超细颗粒聚团流化的临界流化速度

发布时间：2018-10-08 10:43

【摘要】：在内径50 mm的流化床实验台上,测量SiO_2、Al_2O_3和TiO_2 3种超细颗粒原生粒径从30 nm增加到5μm的临界流化速度(Umf),并以Geldart A类颗粒(粒径45μm)为参照。结果表明:3种超细颗粒的Umf随粒径的变化规律一致,随原生粒径从30 nm增加到5μm,Umf逐渐增大;当颗粒粒径增加到45μm,Umf大幅度减小,其与原生粒径为30和200 nm时接近。对于不同材料,Umf由大至小的顺序依次为TiO_2、Al_2O_3、SiO_2。粉体安息角测量表明:对于同种材料颗粒,原生粒径对超细颗粒的Umf和安息角的影响规律一致,即5μm超细颗粒的安息角最大。聚团尺寸模型计算表明:稳定流化时,聚团尺寸随原生粒径的变化趋势以及随不同材料的变化趋势均与Umf的变化趋势一致。研究结果为超细颗粒流化临界速度预测研究奠定了基础。
[Abstract]:On a fluidized bed with 50 mm inner diameter, the critical fluidization rate (Umf),) of three kinds of ultrafine particles, SiO_2,Al_2O_3 and TiO_2, was measured from 30 nm to 5 渭 m, and the Geldart A particle size (45 渭 m) was used as a reference. The results show that the Umf of the three kinds of ultrafine particles is consistent with the particle size, increasing from 30 nm to 5 渭 m Umf, and decreasing significantly when the particle size increases to 45 渭 m Umf, which is close to the original particle size of 30 and 200 nm. For different materials, the order of UMF from large to small is TiO_2,Al_2O_3,SiO_2.. The measurement of rest angle of powder shows that the influence of primary particle size on Umf and rest angle of ultrafine particles is the same, that is, the rest angle of 5 渭 m ultrafine particles is the largest. The calculation of cluster size model shows that the change trend of cluster size with primary particle size and with different materials is consistent with that of Umf in stable fluidization. The results laid a foundation for predicting the critical velocity of fluidization of ultrafine particles.
【作者单位】：东南大学能源热转换及其过程测控教育部重点实验室;
【基金】：国家自然科学基金项目(51676042)~~
【分类号】：TQ021.1

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