煤焦油二次热解过程中HCN及NH3释放特性研究
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摘要: 对煤焦油中氮在惰性气氛中二次热解生成NOx前驱物HCN及NH3进行了研究。在两段炉固定床反应器上研究了四种煤样的焦油在二次热解过程中NOx前驱物HCN和NH3的释放规律，讨论了煤阶﹑温度以及灰分对焦油二次热解过程中HCN及NH3释放规律的影响，表明随着煤阶的增高，焦油中氮的质量分数减少，HCN和NH3的转化率也随之减少。随着二次热解温度的增高，HCN和NH3的转化率增加，在800 ℃~900 ℃HCN增幅最大，NH3的质量分数在900 ℃以后基本不变。煤中灰分的存在能减少氮在焦油中的质量分数，导致焦油二次热解过程中HCN和NH3的转化率下降。Abstract: The HCN and NH3 formation during tar secondary pyrolysis for four Chinese coals was investigated with a two stage fixed-bed quartz reactor at 600 ℃～1 000 ℃. The influences of coal rank，ash content and temperature were examined. With the increase of coal rank，the nitrogen in coal tar decreases and the conversion of nitrogen to HCN and NH3 decreases. The conversion of nitrogen to HCN and NH3increases with temperature, and HCN reaches the highest yield in the range of temperature from 800 ℃ to 900 ℃. The presence of ash in coal can reduce the content of nitrogen in tar, which gives rise to the decrease of the yield of HCN and NH3 during the secondary pyrolysis of tar.
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