SCI和EI收录∣中国化工学会会刊

中国化学工程学报 ›› 2022, Vol. 50 ›› Issue (10): 85-94.DOI: 10.1016/j.cjche.2022.07.023

• Fluid Dynamics and Transport Phenomena • 上一篇    下一篇

Gas-liquid-liquid slug flow and mass transfer in hydrophilic and hydrophobic microreactors

Yanyan Liu1,2, Chaoqun Yao1, Guangwen Chen1   

  1. 1 Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China;
    2 University of Chinese Academy of Sciences, Beijing 100049, China
  • 收稿日期:2022-03-30 修回日期:2022-07-19 出版日期:2022-10-28 发布日期:2023-01-04
  • 通讯作者: Chaoqun Yao,E-mail:superyao@dicp.ac.cn;Guangwen Chen,E-mail:gwchen@dicp.ac.cn
  • 基金资助:
    We gratefully acknowledge the financial support for this work from National Natural Science Foundation of China (21991103, 92034303, 91634204). Yanyan Liu would like to acknowledge Dr. Lixia Yang for the kind help on the preparation of resazurin solution.

Gas-liquid-liquid slug flow and mass transfer in hydrophilic and hydrophobic microreactors

Yanyan Liu1,2, Chaoqun Yao1, Guangwen Chen1   

  1. 1 Dalian National Laboratory for Clean Energy, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China;
    2 University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2022-03-30 Revised:2022-07-19 Online:2022-10-28 Published:2023-01-04
  • Contact: Chaoqun Yao,E-mail:superyao@dicp.ac.cn;Guangwen Chen,E-mail:gwchen@dicp.ac.cn
  • Supported by:
    We gratefully acknowledge the financial support for this work from National Natural Science Foundation of China (21991103, 92034303, 91634204). Yanyan Liu would like to acknowledge Dr. Lixia Yang for the kind help on the preparation of resazurin solution.

摘要: Gas-liquid-liquid three-phase slug flow was generated in both hydrophilic and hydrophobic microreactors with double T-junctions. The bubble-droplet relative movement and the local mass transfer within the continuous slug and the dispersed droplet were investigated. It was found that bubbles moved faster than droplets under low capillary number (Ca), while droplets moved faster upon the increase of Ca due to the increased inertia. For the first time, we observed that the increased viscosity of droplets fastened the droplet movement. The mass transfer in the continuous slug was dominated by convection, leading to nearly constant global mass transfer coefficient (kLa); while that in the dispersed droplet was dominated by diffusion, resulting in kL decreasing along the channel. Such features are analogical to the corresponding gas-liquid or liquid-liquid two-phase slug flow, but the formation of bubble-droplet clusters caused by relative movement lowered the absolute mass transfer coefficient. These results provide insights for the precise manipulation of gas-liquid-liquid slug flow in microreactors towards process optimization.

关键词: Mass transfer, Multiphase flow, Slug flow, Microreactor, Colorimetric method

Abstract: Gas-liquid-liquid three-phase slug flow was generated in both hydrophilic and hydrophobic microreactors with double T-junctions. The bubble-droplet relative movement and the local mass transfer within the continuous slug and the dispersed droplet were investigated. It was found that bubbles moved faster than droplets under low capillary number (Ca), while droplets moved faster upon the increase of Ca due to the increased inertia. For the first time, we observed that the increased viscosity of droplets fastened the droplet movement. The mass transfer in the continuous slug was dominated by convection, leading to nearly constant global mass transfer coefficient (kLa); while that in the dispersed droplet was dominated by diffusion, resulting in kL decreasing along the channel. Such features are analogical to the corresponding gas-liquid or liquid-liquid two-phase slug flow, but the formation of bubble-droplet clusters caused by relative movement lowered the absolute mass transfer coefficient. These results provide insights for the precise manipulation of gas-liquid-liquid slug flow in microreactors towards process optimization.

Key words: Mass transfer, Multiphase flow, Slug flow, Microreactor, Colorimetric method