气-液-液萃取传质效率的研究

在液-液萃取过程中,提高分散相的表面更新速率可有效提高萃取的传质效率.研究发现,在萃取过程中使用气体搅拌可以增加液液之间的接触面积,促进液相内的湍动和循环.据此,本文在气-液-液萃取条件下对不同填料的传质性能进行了测定.实验表明,通入气相后分散相液滴呈现稳定的“油包气”空心状态,这种结构大大降低了分散相液滴的传质层厚度,减小了传质距离,极大地强化传质效率.在适宜气速下,气-液-液萃取效率较传统萃取效率提高20％～40％.通过与散装填料对比,发现规整填料更利于强化萃取效果,传质效率提高约50％.

Study on the mass transfer efficiency of gas-liquid-liquid extraction process

In the liquid-liquid extraction process the extraction efficiency of the mass transfer can be effectively improved by increasing surface renewal rate of the dispersed phase. It is found that gas mixing in the extraction process can expand the contact area, promote turbulence and recycling in the liquid phase. According to the theory about liquid-liquid extraction, the mass transfer properties of different fillers were determined. Investigation on mass transfer under different fillers showed that the droplets showed steady hollow state, reducing thickness of the mass transfer of droplets, shortening the mass transfer distance, conducing to mass transfer. The extraction effeciency was increased by 20% - 40% with gas-lliquid-liquid extraction at a certain gas speed range, benefiting to mass transfer. By contrast with bulk packing, structured packing is more strengthening extraction efficiency, with an increase 50% on mass transfer efficiency respectively.