Mass Transfer Mechanism of a Water-Sparged Aerocyclone Reactor

Air stripping of ammonia is a widely used process for the pretreatment of wastewater. Scaling and fouling on the packing surface in packed towers and a lower stripping efficiency are the two major problems in this process. New patented equipment that is suitable for the air stripping of wastewater with suspended solids has been developed. Air stripping of ammonia from water with Ca(OH)2, was performed in the newly designed gas-liquid contactor, a water-sparged aerocyclone (WSA). The mechanism of the mass transfer process in the WSA was investigated using a CO2—NaOH rapid pseudo first order reaction system. The results indicated that there is a critical gas phase inlet velocity Ug. When Ug is lower than this value, the increase of the inlet velocity has a double function of both intensifying the liquid side film mass transfer coefficient kL and increasing the specific mass transfer area a; whereas when Ug is larger than this value, the major function of Ug increase is to make the water drops in the WSA broken, increasing the mass transfer area of gas-liquid phases.