流化床中超细颗粒的聚团破碎与供料的实验研究

Study on Agglomerate Breaking and Feeding of Superfine Particles in Fluidized Bed

在内径为40mm的流化床中,以平均粒径为10μm的超细硅粉为物料,在引入振动力和搅拌力、添加粗颗粒的条件下,考察了振动强度、搅拌转速、粗颗粒粒径和添加比例、氮气流速等因素对超细颗粒聚团破碎和供料过程的影响.实验表明,对于10μm的超细硅粉,流化床供料的最佳操作条件为:搅拌转速90r/min,振动频率13.9Hz,粗颗粒粒径300μm,添加比例20%.此时,可以有效破碎聚团,消除节涌,抑制沟流,降低临界流化速度和夹带速度,显著改善超细颗粒的供料效果。

The agglomerate breaking and feeding of superfine particles in a fluidized bed with 40mm I.D. were investigated by using superfine silicon particles with 10μm average diameter as material under addition of coarse particles, vibration and stirring force. The effects of influential factors, including vibration strength, rotational speed of stirrer, diameter and mass percentage of coarse particles, and velocity of nitrogen, on the feeding rate and the ratio of particles to gas were analyzed. With the superfine silicon particles of 10 μm average diameter, the experimental results indicated that the optimal operation conditions for the feeding in fluidized bed were obtained as follows： the rotational speed of stirrer 90 r/min, the frequency of vibration 13.9 Hz, the average diameter of added coarse particles 300 μm, and their added mass percentage 20%. Under the above conditions, the particle agglomerates can be effectively broken, slugging and channeling in the fluidized bed eliminated, and critical fluidization velocity and entrainment velocity lowered. As a result, the feeding effect of superfine particles to the bed can be obviously improved.