内在矿物质对褐煤加氢热解过程中氮迁移的影响  

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

作　　者：郑盼盼 杜玉杰 王永刚[3] 林雄超[3] 汪心想 耿耿 左孟迪 ZHENG Panpan;DU Yujie;WANG Yonggang;LIN Xiongchao;WANG Xinxiang;GENG Geng;ZUO Mengdi(Henan Chemical Industry Research Institute CO.,Ltd.,Zhengzhou 450052,China;Quality Inspection and Analytical Test Research Center,Henan Academy of Sciences,Zhengzhou 450046,China;School of Chemical and Environmental Engineering,China University of Mining and Technology-Beijing,Beijing 100083,China)

机构地区：[1]河南省化工研究所有限责任公司,河南郑州450052 [2]河南省科学院质量检验与分析测试研究中心,河南郑州450046 [3]中国矿业大学(北京)化学与环境工程学院,北京100083

出　　处：《煤炭科学技术》2024年第5期335-344,共10页Coal Science and Technology

基　　金：国家自然科学基金资助项目(21978319,22008253)。

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NH_(3)、HCN、N_(2)、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NH_(3)、HCN、N_(2)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NH_(3)和N_(2)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NH_(3)、N_(2)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NH_(3)。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NH_(3)和N_(2)。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 NH_(3),HCN,N_(2),tar nitrogen,and char nitrogen,as well as the formation of nitrogen functional groups within the char.Quantitative analysis of NH_(3),HCN,N_(2),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,inher-ent minerals significantly enhance the migration of coal nitrogen to NH_(3)and N_(2).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 NH_(3),N_(2)and HCN.Moreover,the decrease in activation energy promotes the formation of volatile matter,prolongs its separation time from the reactor,strengthens i

关 键 词：褐煤 加氢热解 氮迁移 矿物质 氮官能团 

分 类 号：TQ541[化学工程—煤化学工程]