Hydrodynamics and Model of Gas‐liquid Flow in Microbubble Column Reactors

Microbubble column reactors (MBCRs) have the significant advantages of high gas holdup, large gas‐liquid interfacial area, and excellent mass transfer performance, making them attractive for applications such as hydrogenation and oxidation. However, there is still a lack of comprehensive understanding of the gas‐liquid flow behavior in MBCRs. In this work, the effects of gas and liquid superficial velocities on flow regimes, residence time distribution, and gas holdup are investigated. The gas holdup increases linearly with the increase of gas superficial velocity, even in heterogeneous regimes, ranging from 0% to 60% at gas superficial velocities of 0–25 mm/s. Additionally, the gas‐liquid interfacial areas in MBCRs are 1–2 orders of magnitude larger than those in traditional bubble column reactors. A prediction model for gas holdup is established, and the predicted values are in good agreement with the experimental values.