Gas-liquid microdispersion and countercurrent flow in a miniaturized annular rotating device

Abstract

The major challenge for the existing gas–liquid microdispersion devices is that they cannot achieve efficient dispersion performance at high volume ratio of gas to liquid. In this context, a miniaturized annular rotating device (m-ARD) with a high handling capacity, large specific surface area, relatively narrow bubble size distribution, and operating in a countercurrent flow mode had been proposed to achieve efficient gas–liquid microdispersion performance at the high phase ratio of gas to liquid. Variables were investigated to determine the gas hold-up, bubble size and its distribution, and specific surface area. The gas–liquid microdispersion mechanism in the m-ARD was also discussed. Two typical bubble generation routes, namely, churn and dripping flow were observed and a transition map was constructed. Furthermore, the handling capacity, average bubble size, and specific surface area could be up to 30 mL/min, 0.59 mm, and 1000 m2/m3, respectively. More gas inlets could be beneficial for much higher handling capacity. In addition, for predicting the gas hold-up and average bubble size, two dimensionless equations were proposed.