新型脉冲萃取塔存留分数与特性速度

为测试锥形穿流塔板的性能，在内径为75mm的脉冲萃取塔中，以煤油-水和10%磷酸三丁酯/煤油-水为实验体系，在无传质条件下，研究脉冲强度与两相表观流速对分散相存留分数和特性速度的影响。结果表明，在实验范围内，存留分数与分散相流速近似成正比，与连续相流速无关。而随着脉冲强度的增大，存留分数先减小，当脉冲强度达到临界值(Af)_t后，存留分数迅速增大。将此临界值与脉冲筛板塔临界值进行对比，两种体系分别减小约9.7%和41.4%，此外，特性速度随着脉冲强度的增大而减小，且界面张力较低的体系减小幅度更大。在实验结果分析的基础上，利用量纲分析方法得到了存留分数与特性速度的工程经验关联式，预测值与实验值符合较好，相对误差均小于20%，可以应用于脉冲萃取塔的设计计算。

Hold-up and characteristic velocity in a novel pulsed extraction column

The performance of the conical cross flow plate was tested in a pulsed extraction column of 75mm inner diameter, and the effects of pulsed intensity and superficial velocity of both liquid phases on hold-up and characteristic velocity were investigated under no-mass transfer using two systems: kerosene-water and 10% tributyl phosphate in kerosene-water. The results show that the hold-up is approximately proportional to the dispersed phase velocity, while the effects of continuous phase velocity have little impact under experiment operating range. With the increase of pulsed intensity, the hold-up first reduces and when the pulsed intensity reaches the critical value (Af)_t, the hold-up increases rapidly. Compared with the critical value of pulsed sieve plate column, and the two systems decrease about 9.7% and 41.4%, respectively. Moreover, the characteristic velocities decrease with increasing pulsed intensity and the characteristic velocity of the system with lower interfacial tension decreases faster. Based on the analysis of the experimental results, empirical correlations of hold-up and characteristic velocity are proposed by dimensional analysis method, and a good agreement between the experimental values and the predicted values from empirical correlations is proved with the maximum relative errors less than 20%, which can be used for the design calculations of pulsed extraction column.