Study Of Fluidizing Behaviors Of Fine Particles Mixing With Additional Particles In A Conical Bed

Fine particles belong to C particles classified by Geldart. Generally speaking, the diameter of fine particles arranges from 1 nm to 1000 nm. These particles own so many new characteristics and functions that they have wide applications in many industrial fields, especially in material science and catalytic fields. However, their applications in industry have been limited due to the consequence of strong particles to particles cohesiveness. On the other hand, as for the valuable and special characteristics of prompting the contacting between solid and gas, fluidizing technology of fine particles is increasingly gaining importance along with producing, dealing and applying of fine particles in the manufacture industry. However, the fluidization of fine particles easily leads to channeling and bubbling behavior as for the strong cohesiveness between particles. Hence, how to improve the quality of fluidization of fine particles becomes a hot topic today. The fluidization characteristics of original nano particles SiO₂ and TiO₂ mixing with additional particles in a conical bed have been studied. The influence on the fluidization quality of fine particles by added glass beads with different diameter or different quantity has been investigated in detail. As a result, the fluidization quality of fine particles can be improved by added coarse glass beads. To add certain glass beads to the fine particles can avoid the phenomena like channeling flow, slugging and so on. Besides, it also can decline the minimum fluidization velocity. At the same time, we found that the diameter of glass beads d_p = 0.137mm is a critical point by which we can know whether the fluidization system is a separate system or a completely mixed system. On the contrary, fine particles TiO2 can mix with all kinds of glass beads thoroughly and there are no separate phenomena between glass beads and fine particles TiO2. In the last, we draw a best additional proportion between fine particles TiO2 and additional coarse particles under a given diameter of glass beads. Based on the theoretical analyses and experimental investigation, we found that the size of agglomerates in the experiments with glass beads is less than that in the experiments fluidized with only fine particles. Hence, it is proved that adding coarse particles into fine particles can improve the fluidization quality.