空气搅动的填料萃取塔性能实验研究

引　言气体搅动是一种外加能量的萃取方法 .与机械搅拌相比 ,气体搅动的萃取塔内无运动部件 ,操作稳定 ,结构简单 ,能耗低 .过去已有数篇关于气体搅动的混合 -澄清槽[1] 、喷洒塔[2～ 4 ] 、多级连续萃取器[5] 等无填料的萃取过程水力学性能和传质性能的文献报道 .而在填料塔萃取过程中加入气体搅动技术 ,一方面继承了填料可以有效地降低轴向返混的优越性能 ;另一方面 ,通过外加能量进一步强化液 -液两相接触与传质 ,提高传质系数 ,综合了外加能量的萃取技术和填料萃取技术的优点 .关于这方面的内容目前少有报道[6] .1　实验装置与实验方法…

EXPERIMENTAL STUDY ON PACKED EXTRACTION COLUMN AGITATED WITH AIR

Air was fed into a packed extraction column to increase turbulence,enhance liquid droplet dispersion and surface renewal,and thus raise mass transfer area.This led to improvement of liquid-liquid contact and mass transfer.The experiments on hydrodynamics and mass transfer were carried out with air-kerosene (benzoic acid)-water system, and the effect of air agitation was investigated.It is clear from the results that the air hold-up ,dispersed phases hold-up and mass transfer coefficient increase and flooding velocity goes down while increasing superficial air velocity.The over-agitation of air can cause over-dispersion and emulsification of the dispersed phase,deterioration of mass transfer performance,and even flooding.Packing helps to break up the droplet of dispersed phase and can effectively prevent the liquid from longitudinal mixing in extraction column,so the mass transfer performance of packed column is far better than that of non-packed.