搅拌槽中液-液-固三相传质的实验研究

选择欧洲化学工程师协会(EFCE)推荐的典型液-液萃取体系正丁醇-丁二酸-水，加入不同粒径的玻璃珠构成液-液-固三相传质，以去离子水为连续相，正丁醇为分散相，溶质丁二酸从分散相向连续相传质. 利用电导率法测定液-液相传质系数，并考察了搅拌转速、固体质量百分含量、不同桨型(标准Rushton桨、上推式和下推式45°六折叶涡轮桨)、桨中心平面距槽底距离以及固体颗粒粒径对相间传质的影响. 结果表明，在高转速时，惰性固体粒子的存在强化液-液体系的传质. 随着惰性固体含量增大，液-液-固三相传质有一极大值. 粒径大于100 μm 的固体粒子对液-液体系传质系数影响很小. 三种桨中Rushton桨的对流传质效果最好.

Preliminary Investigation on Interphase Mass Transfer in Agitated Liquid-Liquid-Solid Dispersion

Volumetric mass transfer coefficients were determined for liquid-liquid-solid dispersion in a mechanically agitated baffled tank with internal diameter D=0.118 m. The effects of agitation speed (210~460 r/min), inert glass beads diameter (74~355 mm in size), type of impeller (Rushton, PTU, PTD), impeller-to-bottom distance (D/6, D/4, D/3), mass fraction of inert glass particles (<2%) on the mass transfer of typical liquid-liquid extraction system n-butanol-deionized water-succinic acid were examined. The data were collected on-line using a conductivity probe and processed with a PC computer. The mass transfer coefficients of liquid-liquid and liquid-liquid-solid systems were compared under the same operation conditions. It is revealed that the presence of a solid phase enhances the interphase mass transfer. The experimental results are discussed in light of hydrodynamics in stirred tanks.