燃料特性对铁矿石烧结及烟气排放的影响

采用烧结杯试验,从固体燃烧角度出发,探究燃料结构和粒度对燃烧前锋温度及烧结气氛变化的影响。结果表明:随着燃料中煤粉比例逐渐提高(0~100%),烧结速度提高至4.32 mm/min,利用系数提高至0.13 t/(m2·h);转鼓强度先上升后下降,当煤粉比例为25%时,转鼓指数达到最高(58.4%);烟气中NO_x浓度与CO成分分别提高28.34 mg/m3和0.72%,CO能促进NO的还原反应,抑制NO_x生成。全煤条件下,随着煤粉粒径<1 mm的质量分数由50%降低到10%,烟气中NO_x降低了51.33 mg/m3,提高燃料粒度可降低烟气NO_x排放浓度;而延长烧结时间,NO_x总排放量上升。研究结果可为烧结燃料选择及烟气减排提供参考。

EFFECT OF FUEL CHARACTERISTICS ON SINTERING AND FLUE GAS EMISSION OF IRON ORE

From the view of solid combustion, the influence of fuel proportioning and particle size on the temperature of combustion layer and sintering atmosphere were studied by sintering pot experiment. The results showed that as the proportion of pulverized coal in the fuel increased from 0 to 100%, the sintering speed and utilization coefficient increased to 4.32 mm/min and 0.13 t/(m2·h), respectively. The sinter drum strength first increased and then decreased, and the drum index reached the peak value of 58.4%, when the pulverized coal ratio was 25%. The NO_x concentration in the flue gas was increased by 28.34 mg/m3, and the CO content was increased by 0.72%. CO promoted the reduction reaction of NO and inhibited the formation of NO_x. Under full coal condition, with the percentage of fuel with particle size less than 1 mm reduced from 50% to 10%, NO_x in flue gas decreased by 51.33 mg/m3; increasing the fuel particle size could reduce the concentration of NO_x emission in flue gas. While the sintering time was prolonged, the total NO_x emission was increased. The research results could provide theoretical guidance and reference for sintering fuel selection and the reduction of flue gas emission.