气固逆流下行流化床中颗粒速度的径向与轴向分布  

Radial and Axial Distributions of Particle Velocity in a Counter-current Fluidized Bed

作　　者：李正杰[1,2] 董鹏飞[1,2] 宋文立[1] 范垂钢[1] 李松庚[1] 林伟刚[1] 

机构地区：[1]中国科学院过程工程研究所多相复杂系统国家重点实验室,北京100190 [2]中国科学院研究生院,北京100049

出　　处：《过程工程学报》2012年第3期376-381,共6页The Chinese Journal of Process Engineering

基　　金：国家自然科学基金委员会与神华集团联合资助项目(编号:51174284);中国科学院战略性先导科技专项基金资助项目(编号:XDA07010200)

摘　　要：在内径90mm、高7m的逆流下行床冷态实验装置中,研究了气固逆流下行床中循环锅炉灰(dp300m)颗粒速度的径向分布及其沿轴向发展.结果表明,局部颗粒速度沿径向分布是不均匀的,在完全发展区,颗粒速度中心和边壁低、在r/R0.85附近颗粒速度最大.由大量实验数据回归出预测充分发展段局部颗粒速度的关联式,该公式计算值与实验值的平均相对偏差小于11%.不同径向位置的局部颗粒速度沿轴向的变化趋势不同,边壁区域(r/R0.622)颗粒速度沿轴向单调递增,而中心区域(0r/R0.622)颗粒速度则沿轴向先增大后减小.颗粒速度随逆流气速Ug增大而减小,随颗粒循环速率Gs增大而增大,同时,增大逆流气速可加强颗粒速度径向分布的均匀性.Experiments were carried out in a 90 mm i.d., 7 m high gas upflow and solid downflow fluidized with circulating boiler ash （do=300 μm） to measure the radial profiles of particle velocity and concentration, and its axial development. The results show that particle velocity is lower both in the center and near the wall in the fully developed region. The maximum particle velocity exists at around r/R=0.85. An empirical formula of particle velocity in the developed region is derived from a number of experimental data. Relative errors between calculated values and experiential data are less than ±11%. Local particle velocity in the region near the bed wall （r/R〉0.622） increases along the column. While local particle velocity in the central region （0〈r/R〈0.622） increases first then decreases along the column. Particle velocity decreases with increasing of gas velocity. The uniformity of radial particle velocity profiles increases with increasing of gas velocity.

关 键 词：逆流 下行床 循环锅炉灰 颗粒速度 径向分布 轴向分布 

分 类 号：TQ021[化学工程]