内设中心管的两股催化剂混合预提升管内颗粒速度的分布

采用PV-6D光纤速度仪考察了内设/不设中心管两种催化裂化提升管预提升段内FCC催化剂颗粒速度沿轴、径向的分布，引入径向不均匀指数RNI对颗粒速度的径向不均匀性进行定量分析，并与传统结构内的RNI进行了对比. 结果表明，设中心管的提升段内颗粒速度沿轴向分布更均匀，两种结构内颗粒速度沿径向分布均匀程度扩径区(中心管区)设中心管结构<无中心管结构，底部区及提升管入口区设中心管结构>无中心管结构；相比传统结构，无中心管提升段内RNI减小40%，设中心管减小60%. 给出了设中心管提升段内截面平均颗粒速度轴向分布的经验模型，计算值与实验值吻合较好，可供工程设计参考.

Velocity Distribution of Particles in the Pre-lifting Structure with Two Strands of Catalyst Inlets with Central Tube

The axial and radial distribution characteristics of FCC catalyst particle velocity in two catalytic cracking pre-lifting structures (with and without central tube) were investigated using PV-6D optical fiber probe. The radial non-uniform index was introduced to quantify the heterogeneity of particle velocity. The results show that the particle velocity in the structure with central tube is well distributed in the axial direction. In the expanding area (central tube area), the radial distribution of particle velocity in the structure without central tube is more uniform, while the particle velocity in the structure with central tube is more uniformly distributed in the bottom and riser entrance areas. In addition, compared with the traditional structure, the radial non-uniform index RNI(Up) in the riser of the structure without central tube is decreased by 40%, while RNI(Up) in the structure with central tube is decreased by 60%. The empirical model of axial distribution of cross-sectional averaged particle velocity in the structure with central tube was put forward. The calculated values are in good agreement with the experimental data, which can be used for the purpose of engineering design.