Marangoni效应对填料塔精馏传质过程的影响

通过 4种正体系、 5种负体系的精馏实验 ,考察了Marangoni效应对填料塔中传质过程的影响。结果表明 :正体系的气相体积总传质系数KGa与组成无关 ,仅受气相流量 qG 的影响 ,可用关联式KGa =AqGB,和B =0 .94± 0 .0 4表示 ;而对负体系 ,由于Marangoni效应的存在 ,顺着液相流动方向 ,KGa逐渐减小。其关联式为KGa =AqGBMsC,B =1.0 5± 0 .0 4,C =0 .3± 0 .0 5 ,该式的平均误差约为 6%。

Influence of Marangoni Effect on Mass Transfer in Packed Column Distillation

Influence of Marangoni effect on overall volumetric mass transfer coefficient in packed column was investigated by the distillation experiments of four positive and five negative systems. It is shown that the coefficient K_Ga of the positive systems is independent of composition and only be influenced by the gas flow rate q_G. The experimental data can be well correlated by equation K_Ga=Aq B_G and B=0.94±0.04.However,for the negative systems, K_Ga decreases strongly as the liquid phase flows down the column.The reduction in mass transfer efficiency is caused by a decrease in the effective area for mass transfer due to Marangoni effect. The dimensionless number Ms is defined as |dσ(x *-x)/σdx| to evaluate the influence of Marangoni effect. It is found that K_Ga can be satisfactorily correlated as equation K_Ga=Aq B_GMs C(B=1.05±0.04, C=0.3±0.05),with the average deviation about 6%.