Experimental study on simultaneous desulfurization and denitrification by steelmaking slag for coke oven flue gas [焦炉烟气钢渣湿法联合脱硫脱硝试验研究]

作者：Meng Z.^*; Wang C.; Wang X.; Chen Y.; Li H.

来源：洁净煤技术, 2020, 26(6): 210-216.

DOI：10.13226/j.issn.1006-6772.20020301

• coke oven flue gas
• denitrification
• desulfurization
• steelmaking slag
• wet process

A large amount of flue gas is emitted from the coke production process,and sulfur dioxide(SO2)and nitrogen oxides(NOx)in the flue gas cause environmental pollution.With the increasingly strict air pollutant emission standard of coking industry,in order to solve the air pollution of SO2 and NOx from coke oven flue gas,the combined desulfurization and denitrification experiments of coke oven flue gas in the self-made bubbling reactor were carried out with steel slag as absorbent.The effects of reaction temperature,concentration of steelmak? ing slag slurry,gas flow,SO2 content as well as NO content on SO2 and NO removal efficiency were investigated,and the optimal operat? ing condition was obtained.Results show that the increase in temperature will reduce the reaction rate of NO oxidation,resulting in the de? crease in the concentration of NO2 produced,thereby reducing the denitration efficiency.The increase of slurry concentration will increase the pH value of the slurry and promote NO removal;the increase of the flue gas flow,that is,the decrease of the residence time will reduce the gas-liquid contact time,resulting in the decrease in the desulfurization and denitration efficiency;when the optimal operating condition is reaction temperature of 30 ℃,steelmaking slag slurry concentration of 8% and gas flow of 400 mL/ min,the denitrification efficiency can reach 50.7% and desulphurization efficiency is above 95%.Research on the mechanism of simultaneous desulfurization and denitration of steel slag show that:the OH- dissolved from steel slag can keep the slurry alkaline and has a high pH buffering capacity,which is benefi? cial to the removal of SO2 and NOx;NO reacts with O2 to form NO2,and NO2 reacts with OH- to form NO-2 and NO-3;NO2 reacts with NO to generate N2O3,which is soluble in water,and N2O3 reacts with OH- to generate NO-2,thereby achieving NOx removal.NO is oxidized to NO2 through the gas-phase pre-oxidation method.The results NO2 and N2O3 generated by the reaction of NO2 with NO can be absorbed ef? ficiently by steelmaking slag slurry, thereby reaching the general or ultra - low emission standard of NOx, and achieving industrial application for simultaneous desulfurization and denitration using steelmaking slag.

• 单位
  中国科学院; 中国科学院大学