Liaoning Key Laboratory of Green Development of Mineral Resources, Liaoning Technical University
School of Mining, Liaoning Technical University
China University of Geosciences (Beijing)

低温氮吸附法是目前用于评估直径在0.35nm~300nm之间煤的孔隙结构广泛使用的实验方法,通过实验得到的数据可以表征出煤的孔隙结构特征。在低温氮吸附实验中,样品的粒径、脱气温度和脱气时间等因素对实验结果影响较大。为研究脱气时间对低温氮吸附实验结果的影响,进行了一系列其他条件不变,只改变脱气时间的实验,选择的脱气时间分别为2h,3h,4h,5h,6h,9h,12h,24h。选取三种中煤级煤岩样品为实验材料,分别为济宁三号井气煤、张北矿气煤以及临涣矿焦煤。研究不同脱气时间下中煤级煤样在低温氮吸附实验中孔隙结构的变化,以确定最佳的脱气时间。通过分析煤样的吸附曲线、吸附-脱附曲线“滞后环”、阶段孔容曲线、平均孔径等参数,发现煤样在脱气时间发生变化时,煤样孔隙结构也发生相应的变化。研究发现,煤样在脱气时间为2h和3h时吸附-脱附曲线的类型以H3为主,其孔隙结构简单。煤样测定的平均孔径在脱气时间为3h达到最大值,平均孔径在脱气时间为5h达到最小值。在脱气3h时,水分对煤样孔隙结构的影响可以忽略不计,挥发分对煤样孔隙结构的影响较低,此时煤样的孔隙结构更佳。三种中煤级煤样最佳脱气时间为3h。

The low-temperature nitrogen adsorption method is widely employed for the characterization of pores with diameters ranging from 0.35 nm to nm in coal samples. Experi- mental data obtained from this method provides valuable insights into the pore structure charac- teristics of coal. Various parameters, such as particle size, degassing temperature, and degassing time, play crucial roles in determining the outcomes of low-temperature nitrogen adsorption ex- periments. In this study, a series of experiments was conducted to investigate the effect of degas- sing time on the results of low-temperature nitrogen adsorption experiments, with a focus on var- ying only the degassing time while keeping other factors constant. h, h, h, h, h, h, h, h were selected as degassing time for the experiment. Three kinds of middle-grade coal rock samples sourced from gas coal at Jining No.3 well and Zhangbei mine, as well as coking coal from Linhuan mine were used as raw meterials in the experiment. The evolution of the pore structure of these middle-grade coal samples under different degassing times was examined to de- termine the optimal degassing time. Analysis of the adsorption curve, “hysteresis loop” of ad- sorption-desorption curve, stage pore volume curve, average pore size and other parameters of coal samples reveal significant variations in pore structure as a function of degassing time. Exper- imental results show that coal samples exhibit primarily H3 adsorption-desorption curve after de- gassing for h or h, indicating a relatively simple pore structure. The average pore size of coal samples peak at h of degassing and reach its minimum after h. Notably, a degassing time of h minimizes the influence of moisture and volatiles on the coal pore structure, leading to a more accurate representation of the sample’s pore characteristics. Consequently, it is recommended that the optimal degassing time for middle-grade coal samples from Jining No. well, Linhuan mine and Zhangbei mine is h.

国家自然科学基金项目(42272197,42102223)和辽宁省矿产资源绿色开发重点实验室开放基金项目(LNTU/GDMR-2308).

颜志丰,张旭峰,唐书恒,等.脱气时间对中煤级煤低温氮吸附实验的影响[J].煤炭转化,2024,47(3):59-69

YAN Zhifeng,ZHANG Xufeng,TANG Shuheng,et al.Effect of degassing time on nitrogen adsorption characteristics of middling coal rank coal at low temperature[J].Coal Conversion,2024,47(3):59-69