• 论文
主办单位:煤炭科学研究总院有限公司、中国煤炭学会学术期刊工作委员会
内在矿物质对褐煤加氢热解过程中氮迁移的影响
  • Title

    Effect of inherent minerals on nitrogen migration during hydropyrolysis of brown coal

  • 作者

    郑盼盼杜玉杰王永刚林雄超汪心想耿耿左孟迪

  • Author

    ZHENG Panpan;DU Yujie;WANG Yonggang;LIN Xiongchao;WANG Xinxiang;GENG Geng;ZUO Mengdi

  • 单位

    河南省化工研究所有限责任公司河南省科学院质量检验与分析测试研究中心中国矿业大学(北京) 化学与环境工程学院

  • Organization
    Henan Chemical Industry Research Institute CO., Ltd.
    Quality Inspection and Analytical Test Research Center, Henan Academy of Sciences
    School of Chemical and Environmental Engineering, China University of Mining and Technology-Beijing
  • 摘要

    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。

  • Abstract

    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.

  • 关键词

    褐煤加氢热解氮迁移矿物质氮官能团

  • KeyWords

    brown coal;hydropyrolysis;nitrogen;minerals;nitrogen functional group

  • 基金项目(Foundation)
    国家自然科学基金资助项目(21978319,22008253)
  • DOI
  • 引用格式
    郑盼盼,杜玉杰,王永刚,等. 内在矿物质对褐煤加氢热解过程中氮迁移的影响[J]. 煤炭科学技术,2024,52(5):335−344.
  • Citation
    ZHENG Panpan,DU Yujie,WANG Yonggang,et al. Effect of inherent minerals on nitrogen migration during hydropyrolysis of brown coal[J]. Coal Science and Technology,2024,52(5):335−344.
  • 相关文章
  • 图表

    Table1

    胜利褐煤和脱矿胜利褐煤的煤质分析
    样品 工业分析/% 元素分析/%
    Mad Ad Vdaf FCdaf Cdaf Hdaf Odaf* Ndaf Sdaf
    胜利褐煤 3.36 20.00 45.47 54.53 69.58 4.64 23.74 0.98 1.06
    脱矿胜利褐煤 4.52 0.65 43.10 56.90 66.76 5.77 25.44 1.08 0.95
     注:*通过差减得到。

    Table2

    胜利褐煤的灰分分析
    样品 Aad/%
    SiO2 Al2O3 Fe2O3 CaO MgO K2O Na2O 其他
    胜利褐煤 47.21 22.87 6.97 6.83 3.55 1.47 2.56 8.54

    Table3

    胜利褐煤和脱矿胜利褐煤中含氮官能团的相对含量
    样品 氮官能团相对含量/%
    N−6 N−5 N−Q N−X
    胜利褐煤 23.70 45.57 17.25 13.49
    脱矿胜利褐煤 21.40 46.62 19.93 12.06

    Table4

    胜利褐煤和脱矿胜利褐煤的结构参数
    样品 X射线衍射分析 拉曼光谱分析
    d002/nm Lc/nm La/nm fa ID/IG I (GR + VL + VR)/ID
    胜利褐煤 0.36 1.28 1.12 0.57 0.79 2.61
    脱矿胜利褐煤 0.37 1.32 1.18 0.54 0.78 2.68

    Table5

    胜利褐煤半焦和脱矿胜利褐煤半焦中氮官能团的相对含量
    样品 氮官能团相对含量/%
    N−6 N−5 N−Q
    0.1 MPa胜利褐煤半焦 17.71 31.27 51.02
    0.1 MPa脱矿胜利褐煤半焦 16.82 27.21 55.97
    1 MPa胜利褐煤半焦 28.46 71.54
    1 MPa脱矿胜利褐煤半焦 25.14 74.86
    2 MPa胜利褐煤半焦 25.20 74.80
    2 MPa脱矿胜利褐煤半焦 24.93 75.07
    3 MPa胜利褐煤半焦 18.47 81.53
    3 MPa脱矿胜利褐煤半焦 15.37 84.63
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