Effectiveness of mass transfer in a packed distillation column in relation to surface tension gradients

Effect of Surface Tension on Mass Transfer Devices

“…% aqueous solution of methanol, ethanol, 2-propanol, and the mass transfer coefficient would be reduced with the increased surfactant concentration. Similar to Patberg et al, 1983, Proctor et al, 1998 also discussed effects of surface tension on packed distillation column. The difference between them is that the experimental parameters, include different scale of packed distillation column and liquid flow rate were performed by Proctor et al, 1998.…”

“…This can be called as Marangoni positive system in the packed distillation column. In addition, Patberg et al, 1983 also found that the interface refreshment was affected by the smaller packing and the lower liquid flow rates more significantly. Patberg et al, 1983 assumed that the shear stress was equal to the largest possible surface tension difference divided by an assumed creeping height, which resulted in the constant shear stress and constant thickness of creeping film.…”

“…12, Moens &Bos, 1972 andPatberg et al, 1983 demonstrated that the mass transfer Proctor et al, 1998) performances were increased significantly for the positive system, especially for the smaller packing. Since the size of pool distillation column established by Moens & Bos, 1972 is larger than that of Patberg et al, 1983, the mass transfer performance seems to be increased more significantly across zero driving force. Besides, the relationship between height of transfer unit and liquid rate was established by Proctor et al, 1998 for packed distillation column, as www.intechopen.com shown in Fig.…”

“…The mass transfer performance is always better for this system, and the phenomenon is called as "Marangoni positive system". Extended from the concept of Marangoni effect acting on thin liquid film, effect of surface tension on mass transfer performance of packed distillation column was investigated by Patberg et al, 1983. Since the surface tension of feeding solution was almost not changed while contacting with the reflux, Fig.…”

“…Table 3 lists some studies to elucidate effect of Marangoni effect on mass transfer devices. For the studies of spontaneous Marangoni convection performed by experimental operation, the mass transfer data affected by spontaneous Marangoni convection could be compared with that without spontaneous Marangoni convection or the theoretical data, and the results showed that the mass transfer data affected by spontaneous Marangoni convection were greater than that without spontaneous Marangoni convection or the theoretical data, such as Bakker et al, 1967, Moens, 1972, Patberg et al, 1983, Martin & Perez, 1994, Proctor et al, 1998, and Sun et al, 2002 in Table 3. In addition, most studies attributed the discrepancy between experimental data and predicted results to that the Marangoni effect was not considered into traditional mass transfer theory.…”