C类颗粒添加纳米细粉后的流态化行为研究

Study on flow behaviors of group C particles blended with nano additives

为了研究纳米添加剂对细粉颗粒流化行为的影响,实验选用全床压降、最小流化速度、床层膨胀率、床层塌落曲线等表征细粉颗粒的流化特征。在直径为5.08 cm的小型流化床中研究了纳米添加剂SiO2 (商品牌号R972)对细玻璃珠颗粒(Geldart A和C类颗粒)流化行为的影响。结果表明加入纳米添加剂后,C类颗粒的流动性得到明显的改善。与GeldartA类颗粒相比,经过表面改性的C类颗粒全床和浓相膨胀率更高,意味着更好的气固接触模式;在相同表观气速下,C类颗粒的流化更均匀,散式化程度更高。以上的发现对于C类颗粒的工业应用具有重要意义。

In order to investigate the effect of nano additives on fluidization behaviors of fine particles, normalized pressure drop, minimum fluidization velocity, bed expansion ratio and bed collapse curve were used to characterize their fluidization behaviors. Experiments were performed in a 5.08 cm diameter fluidized bed using fine glass beads(Geldart A and C groups) as particles and SiO2(R972) as nano additives. It is found that the flow properties of group C particles blended with nano additives were significantly improved. Compared to Geldart group A particles, the modified group C particles exhibited higher full bed and dense phase expansion ratios, which indicated a better gas-solid contact. In addition, they achieved more uniform fluidization under the same superficial gas velocity. These findings are of great significance to the application of group C particles in industries.