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Study on intensification of low interfacial tension system in reciprocating plate extraction column

ZHANG Huijuan1,WANG Henan1,ZHANG Lühong1,HAO Li1,2,JIANG Bin1,2   

  1. 1School of Chemical Engineering and Technology,Tianjin University,Tianjin 300072,China;2National Engineering Research Center of Distillation Technology,Tianjin University,Tianjin 300072,China
  • Online:2014-11-01 Published:2014-11-05

往复振动筛板塔对低界面张力体系萃取过程的强化

张慧娟1,王鹤男1,张吕鸿1,郝丽1,2,姜斌1,2   

  1. 1天津大学化工学院,天津 300072;2天津大学精馏技术国家工程研究中心,天津 300072

Abstract: This paper studied the extraction performance of low interfacial tension system n-butanol-succinic acid-water (BSW) in a Reciprocating Plate Extraction Column (RPEC). Water as the solvent, extracted succinic acid from n-butanol phase. The experiment investigated the effects of flow rate,phase ratio, mass transfer direction and reciprocating rate upon the hydrodynamic and mass transfer performance. The results of extraction using stable sieve plate were compared. The results indicated that the reciprocating rate of plates should not be higher than 3.5cm/s to avoid emulsion. When phase ratio was 2.8,the operation approached the flooding point,and the experiment was not stable. The distribution of drops was better and the volumetric mass transfer coefficient was greater under the condition of higher flow rates and larger phase ratio. However, the range of increase was limited by the maximum throughput and the residence time of two phases. Due to its larger interface area, mass transfer direction from dispersed phase to continuous phase was beneficial in improving efficiency. The axial mixing in continuous phase was much more serious than in dispersed phase under the same operation conditions. Compared to stable sieve plate,the reciprocating plates can improve drops distribution increase the processing capacity and intensify mass transfer.

Key words: low interfacial tension, reciprocating plate extraction column, solvent extraction, hydrodynamic, mass transfer, intensification

摘要: 对低界面张力体系正丁醇-丁二酸-水在往复振动筛板塔中的萃取性能进行研究,体系中水为萃取剂,萃取正丁醇中的丁二酸。实验考察了两相流速、相比、传质方向和筛板振动速率对流体力学性能和传质性能的影响,并且与相同操作条件下固定筛板萃取塔的性能作对比。结果表明,筛板振动速率不高于3.5 cm/s的情况下体系没有发生乳化现象,相比增大到2.8时接近液泛点,实验稳定性较差。流速和相比增大能够获得更好的液滴分布和更大的体积传质系数,但增大的幅度要综合考虑设备的最大通量和两相在塔内的停留时间。分散相到连续相的传质方向传质相界面积大,更有利于提高传质效率。相同操作条件下,连续相中的轴向混合远大于分散相的轴向混合。与固定筛板塔的萃取性能相比,振动筛板改善液滴分布、增大处理能力和强化传质的作用都很明显。

关键词: 低界面张力, 往复振动筛板塔, 溶剂萃取, 流体动力学, 传质, 强化