Pulsed Corona Discharge Process for simultaneous removal of SO2/NOx from a Sintering Plant of Steel Works

摘要

For the simultaneous removal of SO2/NOx from an iron-ore sintering plant, industrial plasma experiments have been conducted with a flue gas flow rate of 5,000 Nm~3/hr. The maximum 40kW power using the magnetic pulse compression (MPC) system generates a peak value of 100-150kV pulse voltage with its risetime of 200nsec and full width at half maximum (FWHM) of 500nsec, and with a frequency < 300Hz. The plasma reactor module adopts a wire-plate structure with a gap of 200-400mm ID between plates. Initial concentrations of SO2 and NOx were around 100-150ppm, respectively in the presence of 15% O2 and < 10% H2O. Various reaction parameters such as specific energy (Whr/Nm~3), NH3 injection with corona discharge, flow rate and injection of hydrocarbons were investigated for SO2/NOx removal characteristics. SO2 removal was rather sharply increased by NH3 injection, where gas energization is indispensable for higher performance. NOx removal proportionally increased with increasing energy consumption, which is however significantly limited below 30% at lower energy consumption and practical conditions. The injection of hydrocarbons significantly enhanced the NOx removal rate, resulting in the reduction of energy consumption. About 90/65% of SO2/NOx were simultaneously removed with a specific energy of 3.0Wh/Nm~3 when both NH3 and hydrocarbons were injected. Practical implications that the pilot-scale plasma results provide are further discussed.