阐明内在矿物质对褐煤加氢热解过程中氮迁移的影响对建立褐煤梯级利用过程中含氮物质污染控制方法，实现褐煤的清洁高效利用具有十分重要的指导意义。研究采用固定床反应器进行胜利褐煤加氢热解试验，考察0.1～3 MPa下内在矿物质对煤中氮向热解产物NH₃、HCN、N₂、焦油氮和半焦氮中迁移的影响以及半焦中氮官能团生成的影响。分别采用紫外分光光度计、气相色谱仪和元素分析仪分析气相中的NH₃、HCN、N₂以及焦油氮和半焦氮，采用X光电子能谱仪（XPS）表征半焦中的氮官能团。结果表明：胜利褐煤加氢热解过程中，内在矿物质催化煤中氮向NH₃和N₂迁移；内在矿物质对煤中氮向HCN迁移的影响受热解压力影响，压力为0.1 MPa时，内在矿物质明显阻碍煤中氮向HCN迁移，而压力为1～3 MPa时，内在矿物质基本不影响煤中氮向HCN迁移；内在矿物质阻碍煤中氮向半焦氮和焦油氮迁移；这是由于加氢热解过程中，内在矿物质降低煤热解反应的活化能，致使更多的自由基攻击煤中的含氮杂环，使较多的含氮杂环分解转化为了NH₃、N₂和HCN；热解反应活化能的降低促进了挥发分生成的增加，延长了挥发分从反应器中析出的时间，加强了挥发分的二次反应，进而促使挥发分中HCN和焦油氮发生二次反应生成NH₃。半焦中存在的内在矿物质提高了新生半焦的反应性，加速了半焦与吸附在半焦上的H的反应，促进新生半焦二次反应生成NH₃和N₂。内在矿物质促进热解半焦中吡啶型氮的生成而抑制半焦中季氮的生成。内在矿物质对褐煤加氢热解过程中氮迁移影响的研究结果将为褐煤的清洁高效利用技术的发展提供基础数据和技术支撑。

This study aims to elucidate the influence of inherent minerals on nitrogen migration during the hydropyrolysis of brown coal. Such understanding holds significant importance in establishing pollution control methods for nitrogen substances in the cascade utilization of brown coal and achieving its clean and efficient utilization. The investigation specifically focuses on the hydropyrolysis of Shengli brown coal in a fixed-bed reactor under different pressures (0.1 MPa to 3 MPa). The study discusses the role of inherent minerals in the migration of coal nitrogen to various pyrolysis products, including NH₃, HCN, N₂, tar nitrogen, and char nitrogen, as well as the formation of nitrogen functional groups within the char. Quantitative analysis of NH₃, HCN, N₂, tar nitrogen, and char nitrogen is performed using an ultraviolet-visible spectrophotometer, gas chromatography, and elemental analyzer. Additionally, nitrogen functional groups in chars are detected using X-ray photoelectron spectroscopy (XPS). The results indicate that during the hydropyrolysis of Shengli brown coal, inherent minerals significantly enhance the migration of coal nitrogen to NH₃ and N₂. Effect of inherent minerals on migration of nitrogen from coal to HCN was affected by pyrolysis pressure, the inherent minerals obviously inhibits the conversion of coal nitrogen to HCN at 0.1 MPa, while, their influence on the migration to HCN remains negligible at pressures between 1 MPa and 3 MPa. Furthermore, inherent minerals effectively suppress the generation of char nitrogen and tar nitrogen. This is attributed to the reduction of the activation energy of coal hydropyrolysis reactions by inherent minerals, which results in more free radicals attacking nitrogen-containing heterocycles within the coal. This, in turn, leads to increased more nitrogen-containing heterocycles decomposition and transformation to NH₃, N₂ and HCN. Moreover, the decrease in activation energy promotes the formation of volatile matter, prolongs its separation time from the reactor, strengthens its secondary reactions, and facilitates the generation of NH₃ from HCN and tar nitrogen within volatile matter. Inherent minerals in the char improve the reactivity of new char, speeding up the reaction between char and adsorbed H, which further promotes the secondary generation of NH₃ and N₂. These inherent minerals also facilitate the formation of pyridinic nitrogen in char while inhibiting the production of quaternary nitrogen formation. The findings of this study provide fundamental data and technical support for the development of clean and efficient brown coal utilization technologies.