焦粉约在450℃开始产生NO_x，无烟煤在350℃左右开始产生NO_x。焦粉和无烟煤产生NO_x的浓度分别在600℃和700℃左右迅速升高，此时含N化合物迅速分解，NO_x浓度在800~900℃达到峰值。由于无烟煤中N含量较高，因此无烟煤NO_x的峰值浓度高于焦粉。总的来说，焦粉和无烟煤在升温过程中，NO_x浓度的变化趋势基本一致。

Coke dust starts to produce NOx at about 450°C, and anthracite starts to produce NOx at about 350°C. The concentration of NOx produced by coke dust and anthracite rises rapidly at about 600°C and 700°C, respectively. At this time, N-containing compounds are rapidly decomposed, and the NOx concentration reaches its peak at 800-900°C. Due to the higher N content in anthracite coal, the peak NOx concentration of anthracite coal is higher than that of coke dust. In general, the change trend of NOx concentration in coke powder and anthracite during the heating process is basically the same.