Simultaneous removal of SO2 and NO using a spray dryer absorption (SDA) method combined with O3 oxidation for sintering/pelleting flue gas.

Based on the demand of sintering/pelleting flue gas ultra-low emission, a semi-dry method using a spray dryer absorber (SDA) combined with O3 oxidation was proposed for simultaneous removal of SO2 and NO. Effects of O3 injection site, O3/NO molar ratio, and spray tower temperature on the removal efficiencies were investigated. It was revealed that both desulfurization and denitrification efficiencies could reach to 85% under the conditions of setting O3 injection site inside of tower, O3/NO molar ratio 1.8, spray tower temperature 85°C, Ca/(S + 2 N) molar ratio 2.5 and slurry flow rate 300 mL/hr. CaSO3/Ca(OH)2 mixture slurry was used as absorbent to simulate operating conditions in iron and steel industry. The result shows that the addition of CaSO3 weakens both removal efficiencies. In addition, the reaction mechanism of simultaneous removal of SO2 and NO using SDA combined with O3 oxidation was proposed.