构造煤原生结构煤微孔特征的多重统计对比及其差异成因机制

孔径小于2 nm的微孔孔隙控制着煤的吸附能力,开展构造煤与原生结构煤微孔特征的对比研究有助于厘清构造煤是否具有超强瓦斯吸附能力。为统计确证构造煤与原生结构煤孔径小于2 nm的微孔孔隙是否存在显著差异,判断造成微孔孔隙特征变化的主控因素并探讨其原因,对鹤壁六矿、平顶山八矿和淮南谢桥矿3组采自同一煤层共生的构造煤与原生结构煤煤样,采用CO2吸附法测定了孔径小于2 nm的微孔孔隙特征参数,并基于CART递归分割、LSD多重比较及多元方差分析等统计分析方法对构造煤与原生结构煤的微孔孔容进行了多重统计对比研究。结果表明:1)构造煤与原生结构煤孔径小于2 nm的微孔孔容没有显著差异;2)构造变形作用对孔径小于2nm微孔孔隙变化的影响远小于变质作用;3)构造煤的吸附能力不是构造煤发育煤层易突出的主要原因;4)煤类微晶结构参数的变化是煤微孔形成的主控因素。

Multiple statistical comparison of the micropore structures between the tectonically deformed and undeformed coal particles and cause analysis of the difference

This paper is to introduce a statistical investigation as to whether there exist significant differences in the characteristic features of micropore with their pore diameters less than 2 nanometers between the tectonically deformed and undeformed coal particles so as to find the dominant factors accounting for such differences.For the said purpose,we have managed to take the experimental measures of such micropore structures with the CO2 adsorption method.In doing so,we have chosen 3 groups of deformed and undeformed coal samples from the same coal seam of Hebi 6~ coal mine,Pingdingshan No.8 coal mine and Huainan Xieqiao coal mine,separately and isolatedly.And,then,the pore volume of each group coal samples was put into statistical procession and comparison.And,next,they were let to be partitioned by CART recursive partitioning algorithm to ascertain the boundaries of each peak on the pore volume curves so as for the pore volume of each sample groups and that of the peak value of each coal sample group to be compared via the least-significantdifference (LSD) method.Further multivariate analysis has been done by using the variance (MANOVA) to identify and determine whether the tectonic movement or the metamorphism serves as the dominant factor that results in the formation of the micropore in the coal body,which may help us to make a final analytic discus sion over the potentially profound causes.The results of our analysis and discussion can be shown as follows:(1) For the micropore with the pore diameter less than 2 nanometers,there may not exist any significant difference in the pore volume between the deformed and undeformed coal particles;(2) It is metamorphism rather than the tectonic deformation that account for the difference in the micropore features;(3) There ought to exist a little difference in the adsorption capacities between the deformed and undeformed coal seams,though the adsorption capacity may not be the principal reason for the outburst of the deformed coal seams;(4)The regular changes of the microcrystalline parameters in the coal serve as the chief cause for the formation of micropore in the coal.In addition,with the increase of the coal particle ranks,the distance of the aromatic sheet in the crystal nucleus of the coal particles would become smaller with the increase of the packing degree and ductility of the coal particles.However,the increase of the stacking degree and ductility should be much greater than the decrease of the interlayer space,which may account for the principal cause that results in the more micropores.