Investigation on solubility of multicomponents from semi-anthracite coal and its effect on coal structure by Fourier transform infrared spectroscopy and X-ray diffraction
Investigation on solubility of multicomponents from semi-anthracite coal and its effect on coal structure by Fourier transform infrared spectroscopy and X-ray diffraction
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DOI：
10.1016/j.fuproc.2018.02.018
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发表时间：
2018-06
影响因子：
7.5
通讯作者：
Xiaodong Zhang;Shuo Zhang;Pengpeng Li;Ding Zhe;Hao Zongchao
中科院分区：
文献类型：
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作者：
Xiaodong Zhang;Shuo Zhang;Pengpeng Li;Ding Zhe;Hao Zongchao
煤作为一种由分子大小不同的有机碳质物质和无机矿物组成的沉积岩，经有机溶剂提取和酸溶解后，化学成分和结构发生变化，从而影响煤层气的赋存和运移。为了研究不同溶剂对煤结构的影响，采用四氢呋喃(THF)、二硫化碳(CS2)、盐酸(HCl)和二氧化氯(ClO2)4种单一溶剂和不同处理顺序的有机溶剂和无机溶剂对沁水盆地中部霍尔新河煤矿半无烟煤进行了处理。利用傅立叶变换红外光谱(FTIR)和X射线衍射仪(X射线衍射仪)研究了煤中有机物或无机物的溶解行为，研究了煤中官能团和微晶结构的变化。结果表明，有机溶剂的萃取率显著高于无机溶剂的萃取率，且HCl的溶解度高于ClO2。具体地说，煤中的主要官能团，包括脂肪族、芳香族和含氧官能团，在有机溶剂处理下都有不同程度的下降趋势。此外，无论是有机溶剂还是无机溶剂处理，主要微晶结构参数在芳香碳网络层的垂直方向上增加，但在平行方向上减少，具有溶胀效应。只有经有机溶剂处理后，煤的基本结构单元的d002值才表现出显著增大的特征。但在复合溶剂处理过程中，煤的主要官能团和微晶结构表现出较复杂的特征，主要表现为孔堵塞、孔膨胀或轻微的溶剂滞留现象。根据其变化特征和机理，提出了半无烟煤的化学结构模型，为进一步研究煤的结构提供了参考。
As a sedimentary rock composed of organic carbonaceous matters with different molecular sizes and inorganic minerals, coal can be extracted by organic solvents and dissolved by acids to make chemical compositions and structures changed, thus influencing on the occurrence and migration of coalbed methane (CBM). For the purpose of investigating the impacts of different solvents on coal structure, semi-anthracite coal samples from Huoerxinhe coalmine in the central part of Qinshui Basin were treated by four single solvents (tetrahydrofuran (THF), carbon disulfide (CS2), hydrochloric acid (HCl) and chlorine dioxide (ClO2)), and by combined solvents (an organic solvent and an inorganic solvent with different treatment orders). Then the solubility behaviors of the organic compounds or inorganic matters from coal were investigated and the changes of the functional groups and the microcrystalline structure in coal were addressed using Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The results show the extraction yields of organic solvents are significantly greater than the dissolution yields of inorganic solvents, and the solubility of HCl is relatively higher than that of ClO2. Specifically, main functional groups in coal, including aliphatic, aromatic and oxygen-containing functional groups, have a decline tendency to different degrees under the treatment of organic solvents. Further, main microcrystalline structure parameters increase in vertical direction but reduce in parallel direction of the aromatic carbon network layer with the swelling effect, regardless of an organic solvent or inorganic solvent treatment. Only by the organic solvent treatment, do thed002values of the basic structure unit of coal appear dramatically enlarged characteristics. Whereas, main functional groups and microcrystalline structure in coal show relatively complex features within the combined solvents treatment because of the phenomenon of pore-blockade, pore-expansion or slight solvent retention. Based on the change characteristics and mechanisms, the chemical structure model of semi-anthracite coal is put forward for providing a reference for the further study of coal structure.