O-3 oxidation combined with semi-dry method for simultaneous desulfurization and denitrification of sintering/pelletizing flue gas

With the vigorous development of China's iron and steel industry and the introduction of ultra-low emission policies, the emission of pollutants such as SO2 and NOx has received unprecedented attention. Considering the increase of the proportion of semi-dry desulfurization technology in the desulfurization process, several semi-dry desulphurization technologies such as flue gas circulating fluidized bed (CFB), dense flow absorber (DFA) and spray drying absorption (SDA) are briefly summarized. Moreover, a method for simultaneous treatment of SO2 and NOx in sintering/pelletizing flue gas by O-3 oxidation combined with semi-dry method is introduced. Meantime, the effects of key parameters such as O-3/NO molar ratio, CaSO3, SO2, reaction temperature, Ca/(S+2N) molar ratio, droplet size and approach to adiabatic saturation temperature (AAST) on denitrification and desulfurization are analyzed. Furthermore, the reaction mechanism of denitrification and desulfurization is further elucidated. Finally, the advantages and development prospects of the new technology are proposed. (C) 2020 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V

Simultaneous removal of SO_2 and NO using a spray dryer absorption(SDA) method combined with O_3 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 O_3 oxidation was proposed for simultaneous removal of SO_2 and NO.Effects of O_3 injection site, O_3 /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 O_3 injection site inside of tower, O_3 /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.CaSO_3 /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 CaSO_3 weakens both removal efficiencies.In addition, the reaction mechanism of simultaneous removal of SO_2 and NO using SDA combined with O_3 oxidation was proposed

Simultaneous removal of SO_2 and NO using a spray dryer absorption(SDA) method combined with O_3 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 O_3 oxidation was proposed for simultaneous removal of SO_2 and NO.Effects of O_3 injection site, O_3 /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 O_3 injection site inside of tower, O_3 /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.CaSO_3 /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 CaSO_3 weakens both removal efficiencies.In addition, the reaction mechanism of simultaneous removal of SO_2 and NO using SDA combined with O_3 oxidation was proposed

Simultaneous removal of SO2 and NO using a spray dryer absorption (SDA) method combined with O-3 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 O-3 oxidation was proposed for simultaneous removal of SO2 and NO. Effects of O-3 injection site, O-3/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 O-3 injection site inside of tower, O-3/NO molar ratio 1.8, spray tower temperature 85 degrees 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 O-3 oxidation was proposed. (C) 2020 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V

Simultaneous removal of NO(x)and SO(2)using two-stage O(3)oxidation combined with Ca(OH)(2)absorption

This paper proposes two-stage O(3)oxidation combined with Ca(OH)(2)for simultaneous removal of NO(x)and SO2(NOx: Nitrogen oxides including NO, NO(2)and N2O5). In two-stage oxidation, NO was first oxidized to NO(2)in an oxidation tube, and NO(2)was further oxidized into N(2)O(5)in the spray tower. NO(x)and SO(2)were simultaneously removed in the spray tower. This method can effectively reduce the extra waste of O(3)caused by the decomposition of N2O5, especially at high temperature. Effects of various factors on denitrification efficiency were investigated. The results showed that the NO(x)removal efficiency decreased and O(3)extra consumption ratio increased with the increase of oxidation temperature or oxidation reaction time. When the O-3/NO molar ratio was 1.8, one-stage O(3)oxidation at 150(o)C extra wasted 33.3% of O-3. With the increase of O(3)concentration at site 2, the NO(x)removal efficiency first increased and then stabilized. Compared with the one-stage O(3)oxidation-absorption, the two-stage oxidation-absorption improved NO(x)removal efficiency from 62.5% to 89%. In addition, the increase of CaSO(3)slurry concentration had little effect on the denitrification efficiency

Simultaneous Removal of NOx and SO2 by MgO Combined with O-3 Oxidation: The Influencing Factors and O-3 Consumption Distributions

Simultaneous removal of NOx and SO2 by MgO combined with O-3 oxidation was studied. The effects of the O-3/NO molar ratio, oxidation temperature, and oxidation residence time on N2O5 decomposition and O-3 consumption distributions were systematically illustrated, which is of great significance for improving NOx removal efficiency and reducing O-3 consumption in practical application. When the O-3/NO molar ratio was greater than 1.0, the highest N2O5 yield was achieved at 90 degrees C. The NOx removal efficiency reached 96.5% at an O-3/NO molar ratio of 1.8. The oxidation temperature increased from 90 to 130 degrees C, resulting in the decrease of N2O5 yield, the improvement of O-3-ICC (O-3 invalid cycle consumption) caused by N2O5 decomposition, and the decrease of NOx removal efficiency from 96.5 to 76%. Besides, the effects of pH, SO2 concentration, and MgSO3 addition on NOx removal efficiency were also investigated. The results showed that the removal efficiency of NO(x )decreased with the increase of SO2 concentration, while MgSO3 addition into MgO slurry could promote the absorption of NO2 due to the reaction between NO2 and SO32-