热解及燃烧过程中燃料氮的N_2转化特性

N_2 Formation from Coal Nitrogen During Pyrolysis and Combustion

利用气相色谱设备实验研究了国内4种煤在热解及燃烧过程中煤中燃料氮向N2的转化特性.研究结果表明:在煤的热解过程中,燃料氮能够转化为N2,煤种不同,N2的转化率也不同;神木煤氮的N2转化率最高,焦作煤最低;随热解温度的升高,燃料氮的N2转化率升高;在煤燃烧过程中,燃料氮同样能够转化为对环境无害的N2,转化率同样与温度有关且随着温度的升高而增加,但当燃烧温度达到1 100℃时,除神木煤外,其他煤中燃料氮的N2转化率均有明显下降;无论是热解还是燃烧,所研究煤中的矿物质均能够促进燃料氮向N2的转化;无论脱灰与否,低温燃烧时燃料氮的N2转化率远比低温热解时高,但在1 100℃下的热解与燃烧时,N2转化率与煤种有关.

Four kinds of native coals were applied to investigate for N2 formation from coal nitrogen during pyrolysis or combustion with a gas chromatographic analysis system. The experimental results show that a part of coal nitrogen can be converted into N2 during pyrolysis. The percentage of N2 formation from fuel nitrogen is highest for Shenmu and lowest for Jiaozuo coal. N2 formation percentage formed increases with the increase of temperature. During coal combustion, N2 can also be formed from coal nitrogen, and N2 formation percentage also depends on temperature. The percentage of N2 formation from coal nitrogen increases with temperature at the temperature lower than or equal to 900 ℃ for the coals studied while it decreases obviously at 1 100 ℃ except Shenmu coal. The minerals in the coals studied can enhance the N2 formation whether during pyrolysis or during combustion process. The percentage of N2 formation during low temperature combustion is greater than that during low temperature pyrolysis while it depends on coal types at 1 100℃.