二维三相循环流化床液体停留时间分布的研究

Research on RTD in Two-dimensional Three-phase Circulating Fluidized Bed

用脉冲示踪法对二维三相循环流化床液体停留时间分布 (RTD)进行了测定。在气速 2～ 3m/s,液体循环量 0～0 .35m3 /h ,固体循环量 1.5～ 1.75g/s的范围内测得的液体停留时间分布曲线均有明显的 3峰分布。其中前两峰分布是由于提升管中颗粒与液体之间和液体与气体之间共同作用改变了液体轴向速度分散程度的结果。第三个峰的分布是由于液体进入循环仓循环后在出口处检测的RTD曲线 ,并且提出一维两组分扩散物理叠加模型 ,模型的预测结果与实验获锝的RTD曲线平均误差小于 5 % 。

Pulse tracer method was used to measure the residence time distribution (RTD) in Two-dimensional Three-phase circulating fluidized bed.Under the conditions such as superfical gas velocity 2.0～3.0 m/s,Liquid flux 0～0.35 m 3/h,solid flux 1 5～1 75 g/s,it was found that the RTD curves of liquid have the characteristic three-peak over the whole operating conditions.The former bimodal distribution could be explained by the interaction between particle-liquid and liquid—gas phase,which resulted in the dispersive extent of the liquid axial distribution velocity.The third one could be explained by liquid circulation that come from storehouse.A proposed one-dimensional two components dispersion model could describe the measured the liquid RTD curves satisfactorily.The average error between the data of model and RTD curves of experiment was less than 5%.