| In 2017,China's crude steel production reached 832 million tons,accounting for49.2%of world production.The iron ore sintering,as an important process in iron and steel production,accounts for about 50%of the total emissions of iron and steel industry.,causing the serious environmental pollution.The emission of NO_X during sintering is mainly fuel NO_X.This paper mainly studies the influence of different fuel types,particle size composition and mixing ratio on NO_X emission in fuel combustion process.Meanwhile,the sintering pot testes were also conducted to investigate the emission behavior of NO_X during sintering process,and the indexes of sintering were also carried out.The experimental results of fuel combustion indicate that NO_x concentration increases with increasing H content in the fuel.The concentration of NO_x released from the combustion of anthracitic coal fines is higher than that of NO_x released from coke fines.The higher the N content in the fuel,the more NO_x is released.During the combustion of anthracite coal fines,the conversion rate of N increases with the increase of volatile content.Among the three kinds of anthracite coal fines,the N conversion rate of Fengshuo anthracite coal fines is the lowest,which is 18.64%.Among the three coke fines,the N conversion rate of Hanggui coke fines is the lowest,which is 13.83%.The NO_x concentration increases with the increase of the fuel particle size.When the same fuel has different particle size combinations,the NO_x conversion rate decreases with the decrease of the average fuel particle size.In the combination of Fengshuo anthracite coal fines and Hanggui coke fines,NO_x production and conversion rate are the lowest.The results of sintering pot testes show that the concentration of NO_x increased rapidly after sintering ignition,and the concentration of NO_x maintains at a certain level.When sintering is coming to an end,the concentration of NO_x decreases rapidly.The concentration of NO_x released from anthracite coal fines is higher than the concentration of NO_x released from coke fines.Among the three kinds of anthracite coal fines,the average NO_x emission concentration of Guomao anthracite coal fines is the highest,which is 302 mg/m~3,and the average NO_x emission concentration of Fengshuo anthracite coal fines is the lowest,which is 263 mg/m~3.Among the three coke fines,the average NO_x emission concentration of Jiaohua coke fines is the highest,which is 197 mg/m~3,and the NO_x average emission concentration of Hanggui coke fines is the lowest,which is 158 mg/m~3.When the same fuel has different particle size combinations,the average concentration of NO_x decreases with the decrease of the average fuel particle size.In the combination of Fengshuo anthracite coal fines and Hanggui coke fines,the average emission concentration of NO_x is the lowest.In the process of sintering,the use of low N,low H and low volatile fuel can be considered as a priority.At the same time,under the guarantee of production indicators,the amount of fine-grained fuel can be appropriately increased. |
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