High-alkali coal contains relatively high contents of alkali metals, which can be usually released in the form of gaseous chlorides and hydroxides during combustion. The effect of alkali metals on NO formation is analyzed in an electrical heated drop-tube furnace at 800–1200 °C during coal combustion. Based on experiments and simulations, the mechanisms underlying the effects of Na salts on NO emission are clarified in CO/NH₃/O₂/H₂O/Na additive (NaCl, Na₂SO₄, and NaAc) systems. The results indicate that the yield of NO initially increases and then decreases as the furnace temperature increased. As the temperature increased from 800 to 1000 °C, NO precursors (HCN and NH₃) undergo accelerated oxidation to form NO. When the furnace temperature is greater than 1000 °C, due to the rapid precipitation of volatiles, a local reducing atmosphere is present around the pulverized coal particles, which inhibits NO formation. NaCl and NaAc addition significantly inhibit NO formation. However, the inhibitory effect is weakened at higher temperatures (>1000 °C). The Na₂SO₄ additive exerts little effect on NO generation during combustion because of its stable chemical properties. The same conclusion is also obtained from gaseous experiments showing that NaCl and NaAc significantly inhibit NH₃ oxidation to form NO. Based on the results of calculations, NaCl and NaAc addition inhibits NO formation by promoting the recombination of H, O and OH and reducing the concentrations of radicals. According to the analysis of chemical reactions, the effect of NaCl and NaAc on NO formation is mainly determined by the competitive relationships among multiple reactions.

高碱性煤含有相对较高的碱金属含量，通常在燃烧过程中会以气态氯化物和氢氧化物的形式释放出来。在煤燃烧过程中，在800-1200°C的电加热滴管式炉中分析了碱金属对NO形成的影响。基于实验和模拟，在CO / NH ₃ / O ₂ / H ₂ O / Na添加剂（NaCl，Na ₂ SO ₄和NaAc）系统中阐明了Na盐对NO排放影响的潜在机理。结果表明，随着炉温的升高，NO的收率先升高，然后降低。随着温度从800升至1000°C，NO前体（HCN和NH ₃）经历加速氧化形成NO。当炉温高于1000°C时，由于挥发物的快速沉淀，煤粉颗粒周围会出现局部还原性气氛，这会抑制NO的形成。加入NaCl和NaAc会显着抑制NO的形成。但是，在较高温度（> 1000°C）下抑制作用减弱。Na ₂ SO ₄添加剂具有稳定的化学性质，因此对燃烧过程中的NO生成几乎没有影响。从气体实验中也可以得出相同的结论，表明NaCl和NaAc可以显着抑制NH _3。氧化形成NO。根据计算结果，添加NaCl和NaAc可通过促进H，O和OH的重组并降低自由基的浓度来抑制NO的形成。根据化学反应的分析，NaCl和NaAc对NO形成的影响主要取决于多个反应之间的竞争关系。