添加NH_4Cl对煤燃烧生成Hg和NO影响的研究

Study on the Effect of NH_4Cl Addition on Hg and NO Produced by Coal Combustion

燃煤中添加的NH4Cl受热会分解成HCl和NH3,对受热分解后产物中氯元素对燃煤烟气汞形态转化的影响和NH3对氧化氮脱除效果进行了数值模拟和实验研究,模拟结果与实验数据趋势基本一致。结果表明:氯元素有利于单质汞向二价汞的转化,烟气中Cl含量越高,Hg(g)到HgCl2(g)转变的温度区间越高,氧化态汞的分布范围越宽;随着NH4Cl喷入量的增加,气态二价汞和单质汞占总汞的百分比都有不同程度的下降,而颗粒态的汞所占比例相应增加,有利于燃煤烟气中汞的脱除;在合适的温度范围内NH3有利于烟气脱硝。

NH4Cl added into the pulverized coal can decompose into HCl and NH3 in the process of combustion, and the effect of chlorine in the decomposed products on mercury speciation transformation and the efficiency of NH3 to remove NOx was numerically simulated and experimentally studied. The numerical results have the same trend as that of eXperiments. The results showed that chlorine helped elemental mercury transform into oxidized mercury, and the higher C1 concentration in the flue gas, the higher the temperature that the Hg（g） is transformed into HgCl2（g）, and the wider the range of oxidized mercury distribution. With increasing of NH4Cl addition, both of the ratios of gaseous oxidized mercury and elemental mercury to total mercury decease to some extent, and the ratio of particulate bounded mercury to total mercury increases accordingly, so as to help mercury removal. NH3 is helpful to remove NOx in the flue gas at suitable temperature range.