Mass Transfer Enhancement by Gas Injection to Liquid-Liquid Slug Flow in Miniaturized Channels

摘要

To increase the maximum flow rate that enables the formation of slug flow in miniaturized channels, gas phase slugs are injected in liquid–liquid slug flow to form gas–liquid–liquid slug flow. The effects of the channel size, the void fraction (the ratio of volumetric flow rate of gas phase to that of total flow rate), the volume ratio of aqueous phase to organic phase on the flow regime and the mass transfer rate are examined. The experimental results show that the region of total flow rate of the liquid phases that forms a stable gas–liquid–liquid slug flow increases as high as 200 mL/min with the air injection (void fraction more than 0.1) in a PTFE tube of i.d. 3 mm. If only liquid two phases are used, the maximum total flow rate to form a stable liquid–liquid slug flow is 60 mL/min. The mass transfer rate in gas–liquid–liquid slug flow is also high since the internal circulation flow is enhanced by the increased flow rate. The mass transfer rate is also correlated with the flow velocity. Through this study, we conclude that the gas–liquid–liquid slug flow is useful in rapid mass transfer operation with a high throughput.