下喷式环流反应器液相流动特性研究

液相停留时间分布分析用于下喷式环流反应器导流筒顶部区域、底部区域、环隙流体流动特性研究。分别将轴向扩散模型应用到各个区域,实验结果表明轴向扩散模型能较好的预测反应器内流体的停留时间分布。采用最小二乘法拟合实验响应曲线,得到模型方程参数。结果表明各个部分的Pe值均随液体喷射速度的增大而减小。导流筒顶部区域的Pe值变化范围为:25.4~6.6;导流筒底部区域的Pe值变化范围为:45.4~11.6;环隙的Pe值变化范围为:60.0~39.2。结果表明导流筒顶部区域返混最大,环隙区域接近于平推流。反应器混和时间随液体喷射速度的增大而减小,变化范围为:88.3~12.5 s。

Flow Behavior of Liquid Phase in Jet-loop Reactor

The residence time distribution analysis was used to investigated the flow behavior in a jet-loop reactor regarded as three different sections which includes the top section of draft-tube,the bottom section of draft-tube and the section of annular gap.The axial dispersion model was applied to the three different sections,respectively.Experimental results showed that the axial dispersion model could predict the residence time distribution of the jet-loop reactor.Fitting the model to an experimental response for an initial Dirac pulse yielded the Pe number for the reactor,caculated for a minimum standard deviation between the predicted and experimental outlet concentration profile,according to the least-square criterion.The range of the Pe numbers in top of the draft-tube,bottom of the draft-tube,annular gap was 25.4～6.6;45.4～11.6;60.0～39.2,repectivly.It showed that the top of the draft-tube had the biggest backmixing and the real flow of the annular section approached the plug flow of the ideal tube.The mixing time of the reactor decreased as the jet velocity increase,the range of value was 88.3～12.5s.