石英砂二元混合颗粒初始流化过程的研究  

Initial Fluidization Processes of Binary Quartz Sand Particles with Equal Density

作　　者：陈晓娜[1,2] 张永民[1] 唐军[1] 黄金库[1] 卢春喜[1] 王祝安[1] 

机构地区：[1]中国石油大学(北京)重质油国家重点实验室,北京102249 [2]中科合成油工程有限公司,北京101407

出　　处：《高校化学工程学报》2013年第5期729-736,共8页Journal of Chemical Engineering of Chinese Universities

基　　金：国家自然科学基金(20906101);国家973项目(2012CB215004)

摘　　要：在一套Φ300 mm×3000 mm的有机玻璃冷模流化床实验装置上,考察了石英砂二元混合颗粒的初始流化特性。所有二元混合颗粒均由颗粒密度相同但粒径不同的A、B、C、D四类颗粒组分两两按照一定质量分数混合而成。采用FXC-Ⅱ/32型压力巡检仪测得了不同轴向位置床层的压降曲线,得到了不同二元混合颗粒的起始流化过程特性曲线和起始流化速度。实验结果表明,两种颗粒组分平均粒径大小和差异及其组分质量分率对二元混合颗粒的起始流化特性具有显著影响。A类颗粒加入可显著改善B、C和D类颗粒的流化质量;C类颗粒加入量过大会使混合颗粒在流化过程中出现严重的沟流现象;当浮升组分(小颗粒)质量分数为0.4时,组分粒径差异较大的二元混合颗粒在流化过程中最容易发生完全分级现象;对于粒径差别较大的二元颗粒组分,床层最小流化速度随小颗粒组分的增多而下降,而对于具有较强颗粒间作用力组分的二元颗粒组分,床层最小流化速度则随小颗粒组分的增多而增大。根据实验数据对等密度BD二元混合颗粒的起始流化速度预测公式进行了修正,发现实验值与计算值吻合较好。The initial fluidization processes of binary mixture particles of quartz sands are studied in an experimental fluidization cold model made ofperspex with the dimensions of Ф300mm×3000mm. Four quartz sand particle groups with equal particle density and different mean diameters, corresponding to Groups A, B, C, D according to the Geldart classification method, respectively, were used. Different two groups of particles with different mass fractions mixing together forms the different binary particle systems in this study. The initial fluidization curves （Ap-Ug） and minimum fluidization velocities Umf were measured by a FXC- Ⅱ/32 pressure measurement system. Experimental results show that, for each binary particle mixture, the particle sizes, size difference and mass fractions of the two particle components have important impacts on its initial fluidization properties. It was observed that Group A component can improve the fluidization quality of other components, i.e. the Group B, C, D component. With too much Group C component, binary particle mixtures show serious channeling in the initial fluidization process. There exists a critical mass fraction for the flotsam component （i.e. particle component with smaller mean diameter） xf=0.4, under which the complete segregation of the two particle components is readily to happen during initial fluidization processes. For binary mixtures with large particle size differences, the minimum fluidize velocity Umf decreases with increasing smaller particle fraction However, for binary mixtures with one component having strong inter-particle forces, umf increases withincreasing smaller particle fraction. Finally, in this study a modification was made for the existing umf correlation of the BD binary mixture, which has better agreements among the measured and predicted results.

关 键 词：二元混合颗粒 起始流化特性 分级 沟流 质量分数 

分 类 号：TQ026.7[化学工程]