INDUSTRIAL PLASMA EXPERIMENTS FOR SIMULTANEOUS REMOVAL OF SO<sub>2</sub>/NO<sub>x</sub> FROM A COAL-FIRED POWER PLANT

Nam, Chang Mo; Jang, Kyung Ryong; Kang, Yong

Environmental Engineering Research 2000;5(4): 199-206.

INDUSTRIAL PLASMA EXPERIMENTS FOR SIMULTANEOUS REMOVAL OF SO₂/NO_x FROM A COAL-FIRED POWER PLANT

Chang Mo Nam¹^†, Kyung Ryong Jang¹, and Yong Kang²

¹Environmental Research Group, Korea Electric Power Research Institute, Taejon 305-380, Korea
²Department of Chemical Engineering, Chungnam National University, Taejon 305-701, Korea

Corresponding Author: Chang Mo Nam ,

Received: August 17, 2000; Accepted: November 16, 2000.

ABSTRACT

Experimental investigations for simultaneous removal of SO₂/NO_x were performed using the pulsed corona discharge process under coal-fired, pilot-scale flue gas conditions. A pulse voltage of 70kV, its risetime of 200 nsec and total duration of 500 nsec were generated using a thyristor-type spark gap switch. Initial concentrations of SO₂ and NO_x were around 340 and 150 ppm in the presence of 4% O₂ and 6 — 8% H₂O. Various reaction parameters such as specific energy (Whr/Nm³), NH₃ injection with/without corona discharges, gas temperature and C₂H₄ injection were investigated for SO₂/NO_x removal characteristics. SO₂ removal was rather dependent on temperature and NH₃, but the influence of energy consumption into the gas remained negligible. NO_x removal efficiency increased with increasing energy consumption, but at lower energy consumption (<5 Whr/Nm³), NO to NO₂ conversion was significantly limited below 30%. However, NO₂ removal rate was sharply increased with C₂H₄ injection by which energy consumption was significantly reduced. The effects of residence time and frequency were also discussed. Consequently, about 90/65% simultaneous removal of SO₂/NO_x was achieved at 4.7 Whr/Nm³ when both NH₃ and C₂H₄ additives were injected.