氨气(NH₃)作为零碳富氢燃料，在燃煤锅炉中掺烧NH₃是从燃烧源减少碳排放的有效途径，但会带来NO_x排放升高和煤粉燃尽变差等问题。为实现燃煤锅炉掺烧NH₃的低NO_x排放，在自行搭建的气流床半气化燃烧实验台上探究了气化炉掺烧20%的NH₃(G-20%NH₃)和燃烧室掺烧20%的NH₃(C-20%NH₃)中燃料氮的转化和NO_x排放特性。研究发现，气化炉内掺烧NH₃会降低炉膛温度，但对煤粉的气化反应影响较小，与纯煤工况相比，煤氮的转化率仅降低了3.64%，挥发分和固定碳转化率分别仅降低了0.70%和2.54%。在气化炉掺烧NH₃中，NH₃在气化炉中的转化率可达69.55%。气化炉内总燃料氮向N₂的转化率为68.88%，其中NH₃-N向N₂的转化率为67.73%。同时，气化炉掺烧NH₃促进了煤-N和NH₃-N向HCN的转化，转化率为0.36%。气化炉中煤粉的热解促进了NH₃的热解，相较于纯煤，气化炉掺烧NH₃使气化炉出口H₂体积分数升高了69.23%。掺烧NH₃降低了燃烧室燃烧初期的温度分布。相较于纯煤，气化炉和燃烧室掺烧NH₃使燃烧室的温度峰值分别降低了46 ℃和62 ℃。但是，掺烧NH₃推迟了气化半焦的燃烧，增加了燃尽区的温度。气化炉和燃烧室掺烧NH₃中燃尽区平均温度比纯煤工况分别升高了135.8 ℃和72.8 ℃，促进了煤粉的燃尽。其中燃烧室掺烧NH₃的促进效果更为显著，相较于纯煤，C-20%NH₃中飞灰含碳降低了1.8%。但气化炉掺烧NH₃更有利于降低NO_x排放，相较于C-20%NH₃，G-20%NH₃的NO排放降低了23.51%。

Ammonia (NH₃) is a carbon-free and hydrogen-rich fuel. NH₃ co-firing in coal-fired boiler is an effective approach to reduce carbon emissions from the combustion source. However, it can lead to problems such as high NO_x emissions and poor coal burnout. To address the issues above, this paper investigated the Fuel-N conversion and NO_x emissions during co-firing 20%NH₃ in gasifier (G-20% NH₃) and in combustor (C-20%NH₃) using a self-built mild gasification-combustion experimental rig. The research found that the co-firing NH₃ in the gasifier can decrease the gasifier temperature. However, it has little effect on the coal gasification reactions in gasifier. Compared with a pure coal condition, the conversion ratio of coal-nitrogen was only reduced by 3.64%, and the conversion ratio of volatile matter and fixed carbon decreased by only 0.70% and 2.54%, respectively. Besides, the conversion of NH₃ in the gasifier can reach 69.55% during the condition of G-20%NH₃. The 68.88% of total fuel-N was conversed to N₂ in the gasifier, with NH₃-N converting to N₂ was 67.73% in G-20%NH₃. In addition, the NH₃ co-firing in the gasifier promoted the transformation of coal-N and NH₃-N to HCN, with the value of 0.36%. Moreover, the coal pyrolysis in the gasifier promoted the NH₃ pyrolysis. Compared with pure coal, the NH₃ co-firing in the gasifier increased the H₂ concentration at the outlet of the gasifier by 69.23% than that of pure coal. The NH₃ co-firing also decreased the temperature during the preliminary stage of combustion. Compared with pure coal, the NH₃ co-firing in the gasifier and combustor decreased the temperature peak by 46 ℃ and 62 ℃, respectively. Simultaneously, the NH₃ co-firing delayed the occurrence of temperature peaks. Additionally, the NH₃ co-firing delayed the gasified char combustion in the combustor. The average temperature in the burnout zone increased by 135.8 ℃ and 72.8 ℃ during G-20%NH₃ and C-20%NH₃, respectively, compared to PC. It was more conducive to the burnout of pulverized coal. The NH₃-cofiring in combustor had more significant promoting effects on the burnout of pulverized coal, in which the unburned carbon in fly ash decreased by 1.8% compared PC. However, the NH₃ co-firing in gasifier was more effective in reducing NO_x emissions. During the G-20%NH₃, NO emissions were decreased by 23.51% compared to C-20%NH₃. The study offers some innovative ideas and data reference for the development of low NO_x emission technology for NH₃ co-firing in coal-fired boiler.