SCI和EI收录∣中国化工学会会刊

Chinese Journal of Chemical Engineering ›› 2020, Vol. 28 ›› Issue (1): 33-45.DOI: 10.1016/j.cjche.2019.07.022

• Fluid Dynamics and Transport Phenomena • Previous Articles     Next Articles

An experimental study of immiscible liquid-liquid dispersions in a pump-mixer of mixer-settler

Qiao Tang1, Jiyizhe Zhang1, Yuxin Wu1, Yundong Wang1, Zuohua Liu2   

  1. 1 State Key Laboratory of Chemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China;
    2 School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044, China
  • Received:2019-04-25 Revised:2019-06-06 Online:2020-03-31 Published:2020-01-28
  • Contact: Yundong Wang, Zuohua Liu
  • Supported by:
    Supported by the National Natural Science Foundation of China (NSFC) (21636004), the National Safety Academy Foundation (U1530107), the National Basic Research Program of China (2012CBA01203).

An experimental study of immiscible liquid-liquid dispersions in a pump-mixer of mixer-settler

Qiao Tang1, Jiyizhe Zhang1, Yuxin Wu1, Yundong Wang1, Zuohua Liu2   

  1. 1 State Key Laboratory of Chemical Engineering, Department of Chemical Engineering, Tsinghua University, Beijing 100084, China;
    2 School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400044, China
  • 通讯作者: Yundong Wang, Zuohua Liu
  • 基金资助:
    Supported by the National Natural Science Foundation of China (NSFC) (21636004), the National Safety Academy Foundation (U1530107), the National Basic Research Program of China (2012CBA01203).

Abstract: Drop size distribution (DSD) or mean droplet size (d32) and liquid holdup are two key parameters in a liquid-liquid extraction process. Understanding and accurately predicting those parameters are of great importance in the optimal design of extraction columns as well as mixer-settlers. In this paper, the method of built-in endoscopic probe combined with pulse laser was adopted to measure the droplet size in liquid-liquid dispersions with a pump-impeller in a rectangular mixer. The dispersion law of droplets with holdup range 1% to 24% in batch process and larger flow ratio range 1/5 to 5/1 in continuous process was studied. Under the batch operation condition, the DSD abided by log-normal distribution. With the increase of impeller speed or decrease of dispersed phase holdup, the d32 decreased. In addition, a prediction model of d32 of kerosene/deionized system was established as d32/D=0.13(1+5.9φ)We-0.6. Under the continuous operation condition, the general model for droplet size prediction of kerosene/water system was presented as d32/D=C3(1+C4φ)We-0.6. For the surfactant system and extraction system, the prediction models met a general model as d32/D=nWe-0.6.

Key words: Dispersion, Droplet size distribution, Liquid-liquid, Mean drop size, Mixer-settler

摘要: Drop size distribution (DSD) or mean droplet size (d32) and liquid holdup are two key parameters in a liquid-liquid extraction process. Understanding and accurately predicting those parameters are of great importance in the optimal design of extraction columns as well as mixer-settlers. In this paper, the method of built-in endoscopic probe combined with pulse laser was adopted to measure the droplet size in liquid-liquid dispersions with a pump-impeller in a rectangular mixer. The dispersion law of droplets with holdup range 1% to 24% in batch process and larger flow ratio range 1/5 to 5/1 in continuous process was studied. Under the batch operation condition, the DSD abided by log-normal distribution. With the increase of impeller speed or decrease of dispersed phase holdup, the d32 decreased. In addition, a prediction model of d32 of kerosene/deionized system was established as d32/D=0.13(1+5.9φ)We-0.6. Under the continuous operation condition, the general model for droplet size prediction of kerosene/water system was presented as d32/D=C3(1+C4φ)We-0.6. For the surfactant system and extraction system, the prediction models met a general model as d32/D=nWe-0.6.

关键词: Dispersion, Droplet size distribution, Liquid-liquid, Mean drop size, Mixer-settler