在陕北小保当富镜煤与富惰煤热解焦中氮的赋存形态及转变规律  

Uneven Distribution and Transformation of Nitrogens During Vitrinite-and Inertinite-Rich Coal Pyrolysis Char of Xiaobaodang Coal Mining Area,Northern Shaanxi Province

作　　者：李焕同[1] 邹晓艳 张婷婷 张卫国[1] 王俊淇 LI Huan-tong;ZOU Xiao-yan;ZHANG Ting-ting;ZHANG Wei-guo;WANG Jun-qi(College of Geology and Environment,Xi'an University of Science and Technology,Xi'an 710054,China;College of Urban,Rural Planning and Architectural Engineering,Shangluo University,Shangluo 726000,China)

机构地区：[1]西安科技大学地质与环境学院,陕西西安710054 [2]商洛学院城乡规划与建筑工程学院,陕西商洛726000

出　　处：《光谱学与光谱分析》2025年第5期1494-1500,共7页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(41502160);西安科技大学优秀青年科技基金项目(2019YQ2-08)资助。

摘　　要：以陕北小保当原煤(XR)、富镜质组煤(XV)和富惰质组煤(XI)为研究对象,在高纯Ar气氛下,以5℃·min^(-1)的升温速率在密闭式高温节能气氛炉中进行热解,热解终温度300~900℃。利用热重-差热分析(TG-DTA)、X射线光电子能谱(XPS)分别研究原煤(XR)、富镜煤(XV)和富惰煤(XI)的热解特性及其热解焦中氮赋存形态。结果表明:小保当煤热解过程中,其结构发生分解、解聚反应生成和排出大量挥发物,在440~450℃时,有明显的失重峰,并且富惰煤(XI)的总失重率和最大失重速率均小于富镜煤(XV),是由于惰质组芳构化程度高以及芳环侧链长度短,结构中化学键的离解键能大,热稳定程度高。小保当煤中氮元素的主要存在形式为吡啶型氮(N-6)、吡咯型氮(N-5)、季氮(N-Q)和氮氧化物(N-X),吡咯型氮(N-5)均高于吡啶型氮(N-6),富镜煤中吡咯型氮(N-5)略低于富惰煤,富惰煤中季氮(N-Q)含量略高,主要是由于其芳环缩合程度较高,较多氮元素嵌入大分子多环芳香结构。热解焦中氮元素的主要存在形式为吡啶型氮(N-6)和吡咯型氮(N-5);热解温度在300℃时,吡啶型氮(N-6)和季氮(N-Q)的相对含量明显减少;随温度的升高,吡咯型氮(N-5)向吡啶型氮(N-6)转化;在700℃时,富惰煤中吡啶型氮(N-6)出现拐点,呈现由升转降,可能为芳环化、缩聚作用所致;在900℃时,氮氧化物(N-X)消失。热解焦的表面氮元素多于体相氮元素,富镜煤(XV)和富惰煤(XI)中表面氮元素脱除率分别为53.49%和31.86%;体相氮元素脱除率分别为33.72%和15.84%,在600℃时,N/C出现拐点,呈现由降转升,可能为结构中桥键或烷基侧链的化学键不稳定而发生断裂导致。Xiaobaodang raw coal(XR),vitrinite-rich coal(XV)and inertinite-rich coal(XI)were pyrolyzed in a closed high-temperature energy-saving furnace at a heating rate of 5℃·min^(-1)under high-purity Ar atmosphere.The final pyrolysis temperature was 300~900℃.Thermogravimetric-differential thermal analysis(TG-DTA)and X-ray photoelectron spectroscopy(XPS)were used to study the pyrolysis characteristics of raw coal(XR),vitrinite-rich coal(XV)and inertinite-rich coal(XI),and the occurrence of nitrogen in pyrolysis char.The results show that during the pyrolysis process of Xiaobaodang coal,its structure is decomposed and depolymerized to generate and discharge many volatiles.At 440~450℃,there is an obvious weight loss peak.The total weight loss rate and maximum weight loss rate of inertinite-rich coal(XI)are smaller than those of vitrinite-rich coal(XV),which is due to the high degree of the aromatization of inertinite and the short length of aromatic ring side chain.The dissociation bond energy of chemical bonds in the structure is large and the thermal stability is high.The main forms of nitrogen in Xiaobaodang coal are pyridine nitrogen(N-6),pyrrole nitrogen(N-5),quaternary nitrogen(N-Q)and nitrogen oxide(N-X).Pyrrole nitrogen(N-5)is higher than pyridine nitrogen(N-6).Pyrrole nitrogen(N-5)in vitrinite-rich coal is slightly lower than in inertinite-rich coal.The quaternary nitrogen(N-Q)content in inertinite-rich coal is slightly higher,mainly due to its high degree of aromatic ring condensation and more nitrogen elements embedded in macromolecular polycyclic aromatic structure.The main forms of nitrogen in pyrolysis char are pyridine nitrogen(N-6)and pyrrole nitrogen(N-5).When the pyrolysis temperature was 300℃,the relative content of pyridine nitrogen(N-6)and quaternary nitrogen(N-Q)decreased significantly.With the temperature increase,pyrrole nitrogen(N-5)was converted to pyridine nitrogen(N-6).At 700℃,the pyridine-type nitrogen(N-6)in the inertinite-rich coal group has an inflection point,showing a change from

关 键 词：X射线光电子能谱 富镜煤 富惰煤 热解 氮迁移 

分 类 号：TQ530.2[化学工程—煤化学工程]