载Na胜利褐煤热解过程中氮的迁移转化

采用具有流化床/固定床特征的石英反应器进行不同Na负载量的胜利褐煤热解实验,考察不同Na负载量对煤热解过程中氮迁移的影响。用紫外可见分光光度计分析气相的NH_3和HCN,用X光电子能谱仪(XPS)表征固体半焦中有机氮的存在形式。结果表明,低温热解时,增加Na的含量对煤中氮转化为NH_3起促进作用;高温热解时,Na抑制煤中氮转化为NH_3。Na对煤中氮转化为HCN表现为抑制作用,这种影响规律不随温度而变化。载Na量增加降低半焦氮含量,促进半焦中季氮的生成,但这种影响在低温时不明显。

Transformation of nitrogen during pyrolysis of Na-loaded Shengli brown coal

The impact of Na content on nitrogen transformation during the pyrolysis of Shengli raw coal and the Na-loaded coal in a fixed-bed/fluidized-bed quartz reactor was investigated. The quantification of NH₃ and HCN in gas product was carried out using an ultraviolet-visible spectrophotometer while the occurrence modes of nitrogen in the solid chars were detected by X-ray photoelectron spectroscopy(XPS). The results indicate that the transformation of coal-N to NH₃ can be catalytically enhanced by certain amount of Na at low temperature. When the final pyrolysis temperature is relatively high, the presence of Na appears to inhibit the formation of NH₃. Meanwhile, for any given pyrolysis temperature, the production of HCN will be suppressed by Na. When the pyrolysis temperature is high, the increase of Na content in coal causes the reduction of nitrogen remaining in char and promotes quaternary nitrogen formation, whereas, the effect is negligible at low temperature.