A state of the art treatment route of flue gases using microbubbles

Abstract

The article presents a state-of-the-art method of removal of flue gases through the incorporation of microbubbles in the wet oxidation system. The solubility of SO₂ and NO_X in water is the primary determinant for their simultaneous elimination in the wet oxidation process. SO₂ is soluble in water under specific optimal conditions, but NO_X is nearly insoluble. However, application of suitable oxidants can transform NO/NO₂ into water-soluble HNO₃. In this work, instead of expensive oxidation routes, the enhancement of flue gas mass transfer rate have been tested by incorporating microbubbles in the system. To overcome the challenge of lower NOx reactivity, Hydrogen peroxide served as the primary and only oxidant, while MBs facilitated the solubility and absorption rates of SO₂ and NO_X in water. Several mass transfer properties act as the controlling factors for the process were evaluated to showcase the effectiveness of the process. Sauter mean diameter, gas holdup, specific interfacial area, volumetric coefficient for liquid phase mass transfer, kinetic parameters, Hatta number, and thermodynamic factors were assessed to understand their contribution to the mass transfer and reaction kinetics. The microbubble-assisted H₂O₂ oxidative technique for elimination of SO₂ and NO_X was shown to be highly successful.