方形截面循环悬浮床内边角效应的分析

Analyses of Wall and Corner Effects in Square-cross-section Circulating Suspension Beds

边角效应是方形或矩形截面的循环悬浮床内气固流动结构的重要特点之一。对于烟气脱硫循环悬浮床,减小边壁颗粒层厚度,使床内颗粒径向分布趋向均匀,会有利于气固接触反应,提高脱硫效率。在方形截面循环悬浮床冷态试验台架上,以空气为流化介质,平均粒径40μm的玻璃珠为循环物料,采用双光路光纤浓度测量系统测定了不同轴向高度截面上的径向颗粒浓度分布,分析了床内构件、表观气速和循环流率对边角效应的影响。研究结果对选择操作条件,尤其是合适的循环流率,以及进一步探索改善床内气固流动结构的方向有参考价值。

Wall and Corner Effects are likly the most important characteristics of gassolid flow configuration in the square or rectangle crosssection circulating suspension beds. For the process of flue gas desulfuration in circulating suspension beds, reducing the thickness or density of wall particle layer, which can lead to uniform radial distribution of particles, is propitious to the contact(reaction) between gas and solid, and can improve the desulphurization efficiency. A cold experimental facility of squarecrosssection circulating suspension bed was used in this work. Air was used as the fluidizing medium, and as the circulating material the glass beads with 40μm meandiameter as. The radial densities of particles were measured in the different cross sections of the bed with a double light fibreoptics density probe. The effects of bed geometry, superficial gas velocity and circulating flow rate on the wall and corner particle layer are analyzed from the demonstration of the thickness and the density's change. It was experimentally found that mounting the separating component, choosing smaller gas superficial velocity and suitable particle circulating flow rate are significant for reducing the thickness or density of the wall particle layer. It would be useful in the further research for improving the gassolid flow structure in the desulfuration circulating suspension bed.