The pore characteristics of the low-rank coal are different from medium- and high-rank coals. The low-temperature N2 adsorption (LP-N2A) measurements with a single low-rank coal were launched, and the dynamic change of pore structures under various pretreatment temperatures from 120°C to 300°C was studied. The isothermal curves of the DFS coal sample feature IV type, the hysteresis loops convert from H4 type to H2 type, and the hysteresis loops tend to be closed with the increased pretreatment temperatures. The mesopores are dominant in the DFS coal. The dynamic of pore volume (PV) and pore specific surface area (SSA) features the three-step-style change with the cut-off temperature points at 150°C and 240°C, and this has a relationship with the loss of the moisture and volatiles in the DFS coal sample. The pores with an aperture below 10 nm are the dominant mesopores in the DFS coal, and the mesopore volume features bimodal pattern distribution with a higher left peak of approximately 1.7 nm and a lower right peak of approximately 3-5 nm, and the right peak continuously right shift with the increase pretreatment temperatures. The total mesopore volume decreases with the upgrading temperatures, while the ratio of pores greater than 5 nm increases. Finally, the mesopore evolution model with the increased pretreatment temperatures was summarized.

中文翻译：

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不同预处理温度下低阶煤孔隙结构的动态变化——以鄂尔多斯盆地西南部为例

低阶煤的孔隙特征不同于中高阶煤。开展了单一低阶煤的低温N2吸附（LP-N2A）测量，研究了120°C至300°C不同预处理温度下孔隙结构的动态变化。DFS煤样等温曲线呈IV型，滞后回线由H4型转变为H2型，滞后回线随着预处理温度的升高趋于闭合。中孔在 DFS 煤中占主导地位。孔体积 (PV) 和孔比表面积 (SSA) 的动态特征为三步式变化，截止温度点为 150°C 和 240°C，这与DFS 煤样中的水分和挥发物。孔径小于 10 nm 的孔隙是 DFS 煤中的主要介孔，介孔体积呈双峰分布，左峰高约 1.7 nm，右下峰约 3-5 nm，右峰随着预处理温度的升高不断右移。总介孔体积随温度升高而减小，而大于 5 nm 的孔比例增加。最后，总结了随预处理温度升高的介孔演化模型。总介孔体积随温度升高而减小，而大于 5 nm 的孔比例增加。最后，总结了随预处理温度升高的介孔演化模型。总介孔体积随温度升高而减小，而大于 5 nm 的孔比例增加。最后，总结了随预处理温度升高的介孔演化模型。