Gas-liquid Micro Dispersion and its Performance
Guangsheng Luo,
Professor,
Tsinghua University
Gas-liquid process is one of the most common multiphase processes in chemical industry, and the environmental-friendly, high-effective, safe technology is always a chasing goal. The gas-liquid microreaction technology provides a new opportunity for the intensification of the gas-liquid process, and good gas-liquid microdispersion is the prerequisite for the excellent performance of the subsequent reaction process. Accordingly, this report concentrates on the progress of gas-liquid microdispersion technologies from the development of the microdevice structure and the enhancement of the microdispersion performance. A strategy that changes the gas kinetic energy to generate the desired bubble/liquid slug size and gas-liquid flow regime is proposed to generate the Taylor bubble flow, bubbly flow, and short bubble flow. Besides, by embedding a capillary in the gas channel and introducing a step structure to the liquid channel, the bubble size can easily break through the restriction of microchannel size and can be reduced to 25% of the microchannel size, and the aspect ratio of the Taylor bubble can break through the critical value of 1.0 and be reduced to 0.5. Importantly, the mass transfer specific surface area in the novel gas-liquid microdispersion device is higher up to 10400 m2/m3 and the liquid-side mass transfer coefficient could be larger up to 60×10-4 m/s, which has increased by 30% and 5-9 times compared with the best level in the conventional T-junction microchannel, respectively. Finally, the direction of the gas-liquid microdispersion technology is pointed out.
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