Desulphurization and Simultaneous Treatment of Wastewater from Blast Furnace by Pulsed Corona Discharge

Abstract

Laboratory tests were conducted for removal of SO2 from simulated flue gas and simultaneous treatment of wastewater from blast furnace by pulsed corona discharge. Tests were conducted for the flue gas flow from 12 to 18 Nm3/h, the simulated gas temperature from 80 to 120°C, the inlet flux of wastewater from 33 to 57 L/h, applied voltage from 0 to 27 kV, and SO2 initial concentration was about 1,430 mg/m3. Results showed that wastewater from blast furnace has an excellent ability of desulphurization (about 90%) and pulsed corona discharge can enhance the desulphurization efficiency. Meanwhile, it was observed that the SO2 removal ratio decreased along with increased cycle index, while it increased as the flux of flue gas was reduced, and increased when the flux of wastewater from blast furnace was increased. In addition, results demonstrated that the content of sulfate radical produced in wastewater increase with an increment of applied pulsed voltage, cycle index, or the flux of flue gas. Furthermore, the results indicated that the higher the inlet content of cyanide the better removal effect of it, and the removal rate can reach 99.9% with a residence time of 2.1 s in the pulsed corona zone during the desulphurization process when the inlet content was higher, whereas there was almost no removal effect when the inlet content was lower. This research may attain the objective of waste control, and can provide a new way to remove SO2 from flue gas and simultaneously degrade wastewater from blast furnace for integrated steel plants.