摘要
为研究CO_(2)封存于不可开采煤层后对煤的孔隙结构和分子结构造成的影响,采用低温液氮吸附、低温CO_(2)吸附、傅里叶红外光谱(FTIR)、X射线衍射(XRD)和拉曼光谱(Raman)实验,探究了煤吸附不同压力CO_(2)后的孔隙结构、表面官能团、微晶结构及大分子结构的演变规律。结果表明:煤吸附CO_(2)后微孔的累积比表面积与累积孔体积呈减小趋势,介孔、大孔的累积比表面积与累积孔体积呈增大趋势,微孔的平均孔径整体增大,孔隙结构中微孔向介孔和大孔的方向转变。同时煤芳香烃总体含量减少,芳香层间距d 00_(2)增加,微晶堆积高度L_(c)、晶体堆叠平均层数n、芳香度f_(a)减小,含氧官能团与羟基含量升高,—CH_(2)—含量减小,—CH_(3)含量小幅度升高,CH_(3)/CH_(2)值升高,说明煤吸附CO_(2)后大芳香结构向小芳香结构发展,芳环上的支链逐渐变短且增多,芳香微晶结构被破坏,芳香层堆积的更加松散,导致晶体化程度减小。随着煤吸附CO_(2)压力的升高,D峰和G峰的峰位差d(G-D)减小,强度比I_(D)/I_(G)、D峰半峰宽(FWHM-D)、G峰半峰宽(FWHM-G)与W_(D)/W_(G)值增加,代表缺陷结构的峰面积比A_(S)/A_(total)、A_(S)/A_(D)、A_(D)/A_(G)、A_((GR+VL+VR))/A_(D)值也均增大,这说明煤吸附不同压力的CO_(2)后,煤中大分子结构发生胀裂,石墨结构占比减少且杂质结构占比增加,煤结构整体上朝无序化增强的方向发展。研究结果可为CO_(2)地质封存技术提供理论支撑。
This study examines the impact of CO_(_(2))storage on the pore and molecular structures of coal in unminable coal seams.Low-temperature liquid nitrogen adsorption,low-temperature CO_(_(2))adsorption,Fourier transform infrared spectroscopy(FTIR),X-ray diffraction(XRD),and Raman spectroscopy(Raman)experiments were employed.The evolution rules of pore structure,surface functional groups,macromolecular structure,and microcrystalline structure of coal after CO_(_(2))adsorption at different pressures were investigated.The results showed that,after CO_(_(2))adsorption,the cumulative specific surface area and cumulative pore volume of micropores decreased.In contrast,the cumulative specific surface area and cumulative pore volume of mesopores and macropores increased.The average pore size of micropores increases overall,and the micropores in the pore structure transition to a direction that favors mesopores and macropores.At the same time,the total content of aromatic hydrocarbons in coal decreased,the aromatic layer spacing d 00_(2)increased,the microcrystalline stacking height L_(c),the average number of crystal stacking layers n,the aromaticity f_(a)decreased,the content of oxygen-containing functional groups and hydroxyl groups increased,the content of—CH_(2)—decreased,the content of—CH_(3)increased slightly,and the CH_(3)/CH_(2)value increased.It shows that after the adsorption of CO_(_(2))by coal,the large aromatic structure developed to the small aromatic structure,the branched chain on the aromatic ring gradually became shorter and increased,the aromatic microcrystalline structure was destroyed,and the aromatic layer was more loosely accumulated,resulting in a decrease in the degree of crystallization.With the increase of CO_(_(2))adsorption pressure of coal,the peak position difference d(G-D)between D peak and G peak decreases,the intensity ratio I D/I G,half peak width of D peak(FWHM-D),half peak width of G peak(FWHM-G)and W D/W G values increased,and the peak area ratio A_(S/)A_(total),A_(S)/A_(D),A_(D)/A_(G),A_((GR+VL+VR))/A D values representing the defect structure also increased,it indicates that after coal adsorbed CO_(_(2))under different pressure,the macromolecular structure in coal expanded and cracked,the proportion of graphite structure decreased and the proportion of impurity structure increased.The coal structure as a whole develops in the direction of increasing disorder.The research results provide a theoretical basis for the influence of geological storage of CO_(_(2))on the microscopic properties of coal.The research results provide a theoretical foundation for understanding the impact of geological CO_(_(2))storage.
作者
高飞
林菀
贾喆
白企慧
刘婧
王一凡
李伟英
GAO Fei;LIN Wan;JIA Zhe;BAI Qi-hui;LIU Jing;WANG Yi-fan;LI Wei-ying(School of Safety Science and Engineering,Liaoning Technical University,Huludao 125100,China;Liaoning Technical University-Mine Thermal Power State Key Laboratory of Prevention and Control,Ministry of Education,Huludao 125100,China;PetroChina Jinxi Petrochemical Company,Huludao 125001,China)
出处
《光谱学与光谱分析》
北大核心
2025年第6期1791-1800,共10页
Spectroscopy and Spectral Analysis
基金
国家自然科学基金面上项目(52074147)
2024年辽宁省教育厅基本科研项目(创新发展项目)(LJ242410147082)资助。
