CaCl_2添加对热解煤中汞析出规律影响的实验研究

Experimental study on mercury release behavior during coal pyrolysis with calcium chloride addition

在程序升温热解反应装置上,研究了低氯煤中添加不同氯含量(质量分数0.1%、0.3%、0.5%)的CaCl2对煤热解过程中汞析出规律的影响。实验结果表明,温度是影响汞析出的关键因素;随着氯添加量的增加,Hg2+析出比例呈上升趋势,且汞的最佳析出温度降低,汞的释放率也有所降低;随着热解气氛中O2比例的增加,Hg2+比例也略有增加;较高的升温速率能加快汞的释放,也能提高Hg2+的比例。低氯煤中添加氯化钙能够强化单质汞的氧化。

Mercury release and speciation behavior during coal pyrolysis with the addition of calcium chloride in different chlorine contents of 0.1%,0.3% and 0.5% in mass was studied in a temperature-programmed tube furnace. The concentration of gaseous mercury was monitored online with an online mercury analyzer. The results show that the temperature is a key factor for the mercury releasing during coal pyrolysis. With the rising of calcium chloride addition in coal, the percentage of Hg2＋ increases, while the temperature of maximum mercury releasing and the release of total mercury decrease. The percentage of Hg2＋ also increases to some degrees with the increase of O2 percentage raised. Higher heating rate can promote the mercury release in coal and enhance the proportion of Hg2＋ in flue gas. The study indicates that the calcium chloride addition into the low-chlorine coal can enhance the oxidation of Hg0.