内设/不设中心管两股催化剂混合预提升结构内的颗粒浓度分布

Concentration Distributions of Particles in the Pre-lifting Structure with Two Strands of Catalyst Inlets with and without Central Tube in a Lifting Reactor

采用光纤探针分别考察了内设与不设中心管两种预提升结构内FCC催化剂颗粒浓度的分布,并引入径向不均匀指数RNI(ρ_i)对颗粒浓度径向分布的不均匀性进行定量分析.结果表明,在扩径区(中心管区),内设中心管的预提升结构内颗粒浓度梯度较大;而在提升管入口区,内设中心管的预提升结构内颗粒浓度分布更均匀;相比传统结构,无中心管的提升管入口区内RNI(ρ_i)约减小65%,内设中心管时约减小75%;给出了内设中心管的预提升结构内平均固含率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.

The distribution characteristics of FCC catalyst particle concentration in two catalytic cracking pre-lifting structure（with and without central tube） were investigated using optical fiber. The radial nonuniform index was also introduced to quantify the heterogeneity of particle concentration. The results show that the gradient of particle concentration of the structure with central tube in the expanding area（central tube area）. While in the riser entrance area, the distribution of particle concentration in the structure with central tube is more uniform. Compared with traditional structure, radial Non-uniformity index of particle concentration in the two structures of riser sharply decreases 65% with central tube and 75% without that. The empirical model of the axial distribution of average solid holdup in the structure with central tube was put forward. The calculated values are in good agreement with the experimental ones, it can be used for engineering design purpose.