准东高铁煤与稻草秆热解NOx前驱物释放规律研究

氨(NH_3)和氰氢酸(HCN)是燃料热解过程中的主要含氮化合物,也是燃烧过程中重要的NO_x前驱物,因此研究热解过程中HCN/NH_3的释放规律与转化机制,对降低NO_x排放意义重大。借助热重-质谱联用(TG-MS)系统开展实验研究,探讨了准东高铁煤与稻草秆热解过程中NO_x前驱物的释放规律。研究表明:准东高铁煤与稻草秆的热解产物中,NH_3是主要的NO_x前驱物;NH_3与HNCO、HCN与CH_3CN的释放规律趋同;同等实验条件下,稻草秆热解的NO_x前驱物释放量明显高于准东高铁煤的;准东高铁煤与稻草秆混合热解时,当稻草杆掺混质量百分比从10%增加至40%时,NO_x前驱物的释放量呈先减少后增加的趋势,NO_x前驱物释放量最低时的掺混比为30%,说明稻草秆与准东高铁煤共热解时,二者对NO_x前驱物的释放具有一定的协同耦合抑制作用。

Release of NOx Precursors in Pyrolysis Process of Zhun Dong High-Iron Coal and Straw Stalk

NH₃ and HCN are the main nitrogen containing compound in the pyrolysis process and important NO_x precursors in the combustion process of solid fuel. The conversion and control rules of HCN and NH₃ during the pyrolysis process are of great significance to reduce the NO_x emission. Experiments using the TG-MS technique were carried out to analyze the release behaviors of NO_x precursors in the pyrolysis process of Zhun Dong high-iron content coal and straw stalk. The results indicate that the NH₃ is the main NO_x precursors product in the pyrolysis process of Zhun Dong high-iron content coal and straw stalk. The release behaviors of NH₃ with HNCO and HCN with CH₃CN are similar. The emission of NO_x precursors in the straw stalk pyrolysis process is apparently more than in that of Zhun Dong high-iron content coal. The experiments show that iron compounds and minerals in coal have reduction effects on the NO_x precursors release. In co-pyrolysis process of Zhun Dong high-iron content coal and straw stalk, with the mass percent of straw stalk increased from 10% to 40%, the emission of NO_x precursors is firstly reduced then increased. The emission is the lowest at the mass percent of 30%. It is shown there is synergistic effect on the reduction of NO_x precursors release by the co-pyrolysis of Zhun Dong high-iron content coal and straw stalk.