Effect of gas composition on pulsed corona discharge characteristics and Hg~0 removal performance

【摘要】 Plasma technology effectively removes Hg⁰ by oxidizing it via highly reactive species, offering an efficient and rapid approach for mercury emission control. In this work, we investigated the mechanism of Hg⁰（g） removal by pulsed corona discharge non-thermal plasma in pure N₂ and N₂（80%）-O₂（20%） mixtures（or simulated air）. Experimental and simulation methods were employed to thoroughly investigate corona discharge electrical characteristics, optical properties,and Hg⁰ removal efficiency, while plasma processes and particle evolution mechanisms were analyzed. Hg⁰ was effectively removed in pure N₂ under pulsed corona discharge, achieving 79%efficiency. Despite discharge instability in simulated air due to oxygen’s electronegativity, its strong oxidizing ability enabled nearly complete Hg⁰ oxidation via enhanced plasma chemistry.Mechanistic analysis indicates that the pulse corona discharge generates abundant high-energy electrons and reactive oxygen species, which play a critical role in the effective removal of Hg⁰.The reactive oxygen species in the N₂-O₂ plasma is suggested to be the key issue for improving the efficiency of Hg⁰ removal. The higher electron temperature in simulated air helps provide sufficient reactive conditions for Hg⁰ removal. This research provides valuable insights into the development of more effective non-thermal plasma systems for Hg⁰ control and enhances the theoretical foundation of plasma technology for Hg⁰ removal.更多还原

【Abstract】 Plasma technology effectively removes Hg⁰ by oxidizing it via highly reactive species, offering an efficient and rapid approach for mercury emission control. In this work, we investigated the mechanism of Hg⁰（g） removal by pulsed corona discharge non-thermal plasma in pure N₂ and N₂（80%）-O₂（20%） mixtures（or simulated air）. Experimental and simulation methods were employed to thoroughly investigate corona discharge electrical characteristics, optical properties,and Hg⁰ removal efficiency, while plasma processes and particle evolution mechanisms were analyzed. Hg⁰ was effectively removed in pure N₂ under pulsed corona discharge, achieving 79%efficiency. Despite discharge instability in simulated air due to oxygen’s electronegativity, its strong oxidizing ability enabled nearly complete Hg⁰ oxidation via enhanced plasma chemistry.Mechanistic analysis indicates that the pulse corona discharge generates abundant high-energy electrons and reactive oxygen species, which play a critical role in the effective removal of Hg⁰.The reactive oxygen species in the N₂-O₂ plasma is suggested to be the key issue for improving the efficiency of Hg⁰ removal. The higher electron temperature in simulated air helps provide sufficient reactive conditions for Hg⁰ removal. This research provides valuable insights into the development of more effective non-thermal plasma systems for Hg⁰ control and enhances the theoretical foundation of plasma technology for Hg⁰ removal.更多还原