A new gas–liquid mass transfer enhancement method for a multi-downcomer sieve tray: Bubble breakup by falling droplets

Abstract

Gas–liquid multiphase flows are a significant phenomenon in many chemical processes. Smaller bubbles have higher mass transfer efficiency, so this work proposes a new gas–liquid mass transfer enhancement method for a multi-downcomer sieve tray: bubble breakup by falling droplets. The motion of the bubbles was studied with computational fluid dynamics and particle image velocimetry. The main depth of influence of droplets was determined to be around 15 mm. A droplet breaks a bubble better when the gas velocity is 0.34–0.42 m/s. The droplet enters the liquid layer and acts directly or indirectly on the bubble, increasing its residence time and surface area after large bubbles impacted by droplets are split into smaller ones. The flow field around the bubble changes, the pressure and velocity inside the bubble increase, and the surface renewal accelerates. CO2 absorption experiments show that droplet-broken bubbles enhance the gas–liquid mass transfer effect.