耦合流化床反应器提升管段颗粒速度及滑落的研究

STUDY ON PARTICLE VELOCITY AND SLIPPING IN RISER SECTION OF A COMPOUND FLUIDIZED BED REACTOR

在不同操作条件下,采用PV 4A型颗粒速度、密度测定仪测量了提升管与流化床耦合反应器大型冷态实验装置提升管内速度沿轴向、径向的分布。结果表明,在耦合流化床反应器提升管段,当表观气速一定时,颗粒的时均速度随循环强度的增加而减小;当循环强度相近时,在床层任何轴向、径向位置的颗粒时均速度都随着表观气速的增大而增大。由于提升管出口流化床层及分布器的存在,提升管内轴向速度呈现先增加后减小的分布特征。利用实验数据回归的提升管内颗粒滑落系数的经验模型计算值与实验值吻合较好。

The axial and radial distributions of particle velocity in the riser of a cold model setup,a compound reactor mainly composed of riser and fluidized bed,were investigated by optic fiber probe. The experimental results showed that under a certain superficial gas velocity, the average cross sectional particle velocity reduced with the increase of circulation intensity; at similar circulation intensities,both the axial and radial particle velocities increased with the increase of superficial gas velocities. Due to the existence of a gas-solid dense phase fluidized bed at the riser exit, the axial particle velocity distributions appeared the tendency of increasing with the bed high firstly then gradually decreasing. Furthermore, an empirical model for particle slip coefficient in riser was established based on the experimental data and theoretical analysis,and the calculated values were in good agreement with the experimental data.