SO₂ and NO_x Removal from Combustion Flue Gas by Corona Discharge in Laboratory-Scale Experiment

Abstract

It has been reported that SO₂ and NO_x in flue gas can be removed by corona discharge and that pulsed corona discharge is as energy-efficient as electron-beam treatment. A large amount of data is required, however, to assess the industrial application of the corona discharge method to the removal of SO₂ and NO_x from combustion flue gas. In this study experiments of SO₂ and NO_x removal from actual and simulated combustion gas have been performed on a laboratory scale, where combustion gas composition, temperature, residence time in the discharge duct, and the polarity of high-voltage electrodes are changed for DC and pulsed corona discharge. The following experimental results are obtained: (1) the increase in H₂O and O₂ concentration improves SO₂ and NO_x removal rate, (2) dendritic (NH₄)₂SO₄ powders tend to deposit on high-voltage electrodes, and (3) the electrode polarity has a nominal effect on the removal rate under our experimental conditions.