Considering the complementarity of synchrotron radiation SAXS and nano-CT in the pore structure detection range,synchrotron radiation SAXS and nano-CT methods were combined to characterize the nano-to micropore struct...Considering the complementarity of synchrotron radiation SAXS and nano-CT in the pore structure detection range,synchrotron radiation SAXS and nano-CT methods were combined to characterize the nano-to micropore structure of two bituminous coal samples.In mesopores,the pore size distribution curves exhibit unimodal distribution and the average pore diameters are similar due to the affinity of metamorphic grades of the two samples.In macropores,the sample with higher mineral matter content,especially clay mineral content,has a much higher number of pores.The fractal dimensions representing the pore surface irregularity and the pore structure heterogeneity were also characterized by synchrotron radiation SAXS and nano-CT.The fractal dimensions estimated by both methods for different pore sizes show consistency and the sample with smaller average pore diameters has a more complex pore structure within the full tested range.展开更多
Coal seam CO_(2) sequestration is an important option to address global warming.A better knowledge on coal pore structure evolution during gas adsorption can provide guidance for coal seams CO_(2) seques-tration.Howev...Coal seam CO_(2) sequestration is an important option to address global warming.A better knowledge on coal pore structure evolution during gas adsorption can provide guidance for coal seams CO_(2) seques-tration.However,few investigations on the pore structure evolution differences between the deep and shallow coal were conducted during gas adsorption.In this study,based on the real-time synchrotron radiation small-angle X-ray scattering(SAXS)observation,the average pore diameter and pore surface fractal dimension evolution differences between deep and shallow coal were investigated from the as-pects of coal compositions and stress history.Two types of coal deformation(inner-swelling and outer-swelling)coexist during gas adsorption.Coal compositions have significant impact on the dominance of deformation type.The dominance of inner-swelling in deep coal is induced by the higher ash contents,and there is the decrease of average pore diameter during gas adsorption.The impact of stress-history(burial depth)on adsorption-induced deformation is more prominent than that of gas adsorption ca-pacity.In deep coal,the surface fractal dimension evolution presents a negative correlation with the evolution of pore diameters.In shallow coal,the surface fractal dimension evolution presents a Langmuir-type correlation with the adsorption time.展开更多
基金financially sponsored by the National Natural Science Foundation of China(Grant Nos.U1910206,51861145403,51874312,52004293)China Postdoctoral Science Foundation(No.2018M641526)+2 种基金Yue Qi Distinguished Scholar Project of China University of Mining&Technology(Beijing)Fundamental Research Funds for the Central UniversitiesFund of China Scholarship Council and the Open Project Program of Key Laboratory of Deep Earth Science and Engineering(Sichuan University),Ministry of Education(No.DESE 202004)。
文摘Considering the complementarity of synchrotron radiation SAXS and nano-CT in the pore structure detection range,synchrotron radiation SAXS and nano-CT methods were combined to characterize the nano-to micropore structure of two bituminous coal samples.In mesopores,the pore size distribution curves exhibit unimodal distribution and the average pore diameters are similar due to the affinity of metamorphic grades of the two samples.In macropores,the sample with higher mineral matter content,especially clay mineral content,has a much higher number of pores.The fractal dimensions representing the pore surface irregularity and the pore structure heterogeneity were also characterized by synchrotron radiation SAXS and nano-CT.The fractal dimensions estimated by both methods for different pore sizes show consistency and the sample with smaller average pore diameters has a more complex pore structure within the full tested range.
基金supported by the National Natural Science Foundation of China (grant Nos.U1910206,52004293,52225402)Beijing Natural Science Foundation (grant No.8232057)+4 种基金the Open Project Program of State Key Laboratory of Coal and CBM Co-mining (grant No.2022KF21)Fundamental Research Funds for the Central Universities (grant No.FRF-TP-20-034A1)the Open Project Program of Key Laboratory of Deep Earth Science and Engineering (Sichuan University)Ministry of Education (grant No.DESE 202004)China Postdoctoral Science Foundation (grant No.2018M641526).
文摘Coal seam CO_(2) sequestration is an important option to address global warming.A better knowledge on coal pore structure evolution during gas adsorption can provide guidance for coal seams CO_(2) seques-tration.However,few investigations on the pore structure evolution differences between the deep and shallow coal were conducted during gas adsorption.In this study,based on the real-time synchrotron radiation small-angle X-ray scattering(SAXS)observation,the average pore diameter and pore surface fractal dimension evolution differences between deep and shallow coal were investigated from the as-pects of coal compositions and stress history.Two types of coal deformation(inner-swelling and outer-swelling)coexist during gas adsorption.Coal compositions have significant impact on the dominance of deformation type.The dominance of inner-swelling in deep coal is induced by the higher ash contents,and there is the decrease of average pore diameter during gas adsorption.The impact of stress-history(burial depth)on adsorption-induced deformation is more prominent than that of gas adsorption ca-pacity.In deep coal,the surface fractal dimension evolution presents a negative correlation with the evolution of pore diameters.In shallow coal,the surface fractal dimension evolution presents a Langmuir-type correlation with the adsorption time.
