大型外环流浆态床中宏观流动特性规律研究

STUDY ON THE HYDRODYNAMICS CHARACTERISTICS OF EXTERNAL-LOOP AIRLIFT SLURRY REACTORS

在新型大型浆态床外环流反应器冷模实验装置上,对上升管内的两个重要宏观流动行为参数总体平均气含率和循环浆液速度随表观气速、固含率及下降管流动阻力的变化规律进行研究。结果表明:外环流浆态床上升管中的总体平均气含率随着表观气速和下降管阻力的增加而增大,随着固含率的增加而降低;循环浆液速度随着表观气速的增加而增大,随着固含率和下降管阻力的增加而降低。基于因次分析法和稳态操作条件下的动量守恒原理建立预测上升管内总体平均气含率和循环浆液速度的模型计算式,模型预测值与实验值吻合良好。

The prediction of gas holdup and slurry circulating velocity is important in the design of external-loop airlift slurry reactors.The effect of superficial gas velocity,fine particle concentration,flow resistance of slurry in the downcomer on the overall average gas holdup and slurry circulating velocity were investigated in a novel type of external-loop airlift slurry reactor cold test system.The results suggest that the overall average gas holdup increases with the increase of superficial gas velocity and flow resistance in downcomer,and decreases with the increase of fine particle concentration;the slurry circulating velocity increases with the increase of superficial gas velocity,and decreases with the increase of fine particle concentration and flow resistance in downcomer.An empirical correlation was developed to predict the overall average gas holdup;based on the momentum balance under steady state operating conditions,a model was developed to predict the slurry circulating velocity;on the whole,good agreements between the calculated and measured values were obtained.These results are useful for the design of novel reactor.