Abatement of nitric oxide (NO) through optimized parameters for oxidation induced by pulse corona discharge (PCD).

Abstract

The application of pulsed corona discharge (PCD) for flue gas abatement has gained increasing attention due to its potential as a non-thermal plasma technology for pollutant removal. While PCD has been used for flue gas cleaning, optimising its parameters for enhanced oxidation efficiency remains an area of active research. The study aims to abate NO through the optimised parameters as voltage, frequency, and pulse width, leading to high PCD discharge power and uniform corona discharge intensity for oxidation. A two-stage laboratory-scale PCD reactor was developed to facilitate NO oxidation and conversion. In Reactor 1, NO was oxidised to NO₂, followed by Reactor 2, where steam injection promoted the conversion of NO₂ to nitric acid (HNO₃). Under optimised conditions, the system achieved a NO removal efficiency of 59% with an optimal specific energy consumption of 0.41 kJ/L. The best-performing parameters included 10 kV, 45 kHz frequency, 5.5 µs pulse width, and a gas flow rate of 80 L/min containing 240 ppm NO. To evaluate PCD performance on an industrial scale, a pilot-scale was tested using exhaust gas from Yeongdong Power Plant, achieving a 70% NO-to-NO₂ conversion rate and over 90% deNO_x efficiency. The system operated at 2.1 kW PCD power, 60 kHz frequency, a 30 kW microwave plasma torch, 2000 m³/h gas flow, 380 ppm NO_x, 67°C temperature, 40 L/h steam, and 6 kg/h urea injection. These findings underscore the industrial potential of PCD technology for flue gas treatment, demonstrating its effectiveness in NO abatement while ensuring energy efficiency and scalability.