欢迎访问过程工程学报, 今天是

过程工程学报 ›› 2023, Vol. 23 ›› Issue (5): 681-690.DOI: 10.12034/j.issn.1009-606X.222269

• 研究论文 • 上一篇    下一篇

基于CFD的搅拌萃取塔结构优化与流场分析

袁慎峰， 金玲贞， 陈志荣， 尹红*   

  1. 浙江大学化学工程与生物工程学院，浙江省化工高效制造技术重点实验室，浙江 杭州 310027
  • 收稿日期:2022-07-22 修回日期:2022-09-03 出版日期:2023-05-28 发布日期:2023-06-01
  • 通讯作者: 尹红 yinh@zju.edu.cn

Structural optimization and flow field analysis of agitated extraction column based on CFD

Shenfeng YUAN,  Lingzhen JIN,  Zhirong CHEN,  Hong YIN*   

  1. Zhejiang Provincial Key Laboratory of Advanced Chemical Engineering Manufacture Technology, College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, China
  • Received:2022-07-22 Revised:2022-09-03 Online:2023-05-28 Published:2023-06-01
  • Contact: Hong YIN yinh@zju.edu.cn

RichHTML

PDF

摘要： 为降低搅拌萃取塔内轴向返混并增大通量，在搅拌筛板萃取塔基础上改进内部结构，设计了返混相对较轻的搅拌萃取塔。通过停留时间分布模拟，结合返混模型和流场分析，研究了通道面积、环隙位置、开孔方式和澄清段高度等因素对流体流动特性的影响。结果表明，级间转动挡板可以有效抑制塔内轴向返混，且挡板直径越大，塔内通道面积越窄，抑制返混效果越好；固定环开孔和级间挡板开孔均会带来一定程度的返混，尤以搅拌桨下方的级间挡板开孔影响最为严重；设立澄清段可以降低塔内返混，且澄清段高度越高返混越小，实际应用时考虑到设备成本，澄清段高度与塔径之比以0.7左右为宜。

关键词: 计算流体力学, 搅拌萃取塔, 停留时间分布, 结构优化, 返混模型

Abstract: In order to reduce the axial backmixing and increase the throughout flux in the agitated extraction column, the column was modified on the basis of the agitated sieve plate extraction column, and a new agitated extraction column with relatively light backmixing is proposed. Through the simulation of residence time distribution, combined with backmixing model and flow field analysis, the effects of annulus area, annulus position, opening mode, and the height of settling compartments on fluid flow characteristics are studied. The results show that the inter-stage rotating baffles can effectively inhibit axial backmixing in the column, and the larger the diameter of baffles, that is the narrower the annulus in the column, the smaller the backmixing. The optimum diameter of the inter-stage baffles in the agitated extraction column with a diameter of 50 mm should be more than 25 mm, that is, the ratio of the annulus area to the cross-sectional area of the column should not exceed 25%. Under a certain annulus width, the annulus position has little influence on the fluid flow. When the diameter of the inter-stage baffles is roughly equal to the impellers', the backmixing in the column reaches the smallest. Different opening modes also affect the flow characteristic in the column. Both perforated stators and perforated inter-stage baffles increase backmixing, especially the perforated inter-stage baffles just below the impellers. Under the condition of a certain annulus area, the agitated extraction column A6 without pores in stators and inter-stage baffles has the smallest backmixing and its structure is simple. However, if the liquid-liquid dispersion and the dead zone of the light phase are taken into consideration, the agitated extraction column B3 and B4 not only have relatively low backmixing, but also could improve the throughout flux, whose performance can be further studied. The settling compartments can reduce the backmixing, and the higher the height of settling compartments, the smaller the backmixing. Considering the equipment cost in practical application, the optimum ratio of the height of settling compartment to column diameter should be about 0.7.

Key words: computational fluid dynamics, agitated extraction column, residence time distribution, structural optimization, backmixing model