dual-use of DBD plasma for simultaneous NOₓ and SO₂ removal from coal-combustion flue gas

Dielectric barrier discharge (DBD) was investigated for the simultaneous removal of NOₓ and SO₂ from flue gas in a coal-combustion power plant. The DBD equipment was used in either a mode where flue gas was directed through the discharge zone (direct oxidation), or a mode where produced ozonized air was injected in the flue gas stream (indirect oxidation). Removal efficiencies of SO₂ and NO for both methods were measured and compared. Oxidation of NO is more efficient in the indirect oxidation, while oxidation of SO₂ is more efficient in the direct oxidation. Addition of NH₃, has lead to efficient removal of SO₂, due to thermal reaction, and has also enhanced NO removal due to heterogeneous reactions on the surface of ammonium salt aerosols. In the direct oxidation, concentration of CO increased significantly, while it maintained its level in the indirect oxidation.