煤储层纳米孔隙结构及其瓦斯扩散特征

聂百胜; 伦嘉云; 王科迪; 申杰升; 琚宜文; 张军; 陆卫东

doi:10.3799/dqkx.2018.427

煤储层纳米孔隙结构及其瓦斯扩散特征

doi: 10.3799/dqkx.2018.427

聂百胜^1,2,5,,
伦嘉云^1,2,
王科迪^1,2,
申杰升^1,2,
琚宜文^3,4,5,
张军^1,2,
陆卫东⁵

1.
中国矿业大学共伴生能源精准开采北京市重点实验室, 北京 100083
2.
中国矿业大学煤炭资源与安全开采国家重点实验室, 北京 100083
3.
中国科学院计算地球动力学重点实验室, 北京 100049
4.
中国科学院大学地球科学学院, 北京 100049
5.
新疆工程学院安全工程系, 新疆乌鲁木齐 830023

基金项目:

中央高校基本科研业务费资助项目 2009KZ03

国家自然科学基金项目 51374216

中国科学院战略性先导科技专项 XDA05030100

国家科技重大专项 2011ZX05066-003

"十三五"国家重点研发专项 2016YFC0600708

详细信息

作者简介:
聂百胜(1973-), 男, 教授, 博士生导师, 主要从事煤矿安全方面的研究工作

中图分类号: P618
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- 被引次数: 0
出版历程
- 收稿日期: 2017-10-27
- 刊出日期: 2018-05-15

Characteristics of Nanometer Pore Structure in Coal Reservoir

Nie Baisheng^{1,2,5
,},
Lun Jiayun^1,2,
Wang Kedi^1,2,
Shen Jiesheng^1,2,
Ju Yiwen^3,4,5,
Zhang Jun^1,2,
Lu Weidong⁵

1.
Beijing Key Laboratory for Precise Mining of Intergrown Energy and Resources, China University of Mining & Technology, Beijing 100083, China
2.
State Key Laboratory of Coal Resource and Safe Mining, China University of Mining & Technology, Beijing 100083, China
3.
Key Laboratory of Computational Geodynamics, Chinese Academy of Sciences, Beijing 100049, China
4.
College of Earth Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
5.
Department of Safety Engineering, Xinjiang Institute of Engineering, Urumqi 830023, China

摘要

摘要: 研究煤复杂发育的孔隙结构对揭示煤层气体赋存机理及扩散运移规律有重要意义.为了研究煤的纳米孔隙结构，利用SEM、液氮吸附、小角X射线研究了不同煤阶煤的纳米孔隙在形式和分布上的非均匀性.实验煤样煤基质中的孔呈多峰分布，且孔径范围主要集中在2~10 nm.煤样低温液氮吸附实验测得煤样的吸附量为3.676 cm³/g，煤样的比表面积为1.416 m²/g.以最可几孔径作为研究对象，在实验压力范围内，吸附压力越大，最可几孔径变大的越多；瓦斯气体在纳米级孔隙结构中的扩散模式以过渡型扩散为主，微孔更发达的煤样中，扩散更接近Knudsen型扩散，中孔更发达的煤样中，扩散更接近Fick型扩散；Knudsen数与温度呈负相关关系，温度高于250 K后，Knudsen数趋于稳定，与压强呈正相关关系，压强越大，扩散越容易.
- 孔隙结构 /
- 扩散方式 /
- Knudsen数 /
- 小角X射线散射
Abstract: In order to study the characteristics of nanometer pore structure of coal, the heterogeneous structures of nano pores of different rank coals were investigated by using SEM, liquid nitrogen adsorption and small angle X ray. It is found that the mesopore shows the multimodal division, mainly concentrated in the 2-10 aperture and nm. The adsorption capacity of coal low-temperature nitrogen adsorption experiments of coal samples is 3.676 cm³/g, and coal sample surface area is 1.416 m²/g. By analyzing the most probable aperture, the range of experimental pressure can be found out, and the most probable pore size will be increased with the adsorbent pressure. Gas diffusion model in most nanoscale pore structure model prefers coals mainly concentrated on transitional diffusion. In more developed microporous coal samples (anthracite), the diffusion type is closer to the Knudsen diffusion. In much less developed coal samples, the main diffusion type is closer to Fick diffusion. The Knudsen number is negatively related to temperature, and Knudsen number tends to be stable when the temperature is higher than 250 K, which is positively correlated with the pressure. The diffusion will be easier with the increase of pressure.
- pore structure /
- diffusion model /
- Knudsen number /
- small-angle x-ray scattering

HTML全文

图 1 不同尺度孔隙的测试手段

Fig. 1. Researching methods for different size pores

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图 2 不同煤样的低温液氮等温吸附解吸曲线

Fig. 2. Adsorption/desorption isotherms of different coal samples

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图 3 煤样电镜扫描图像

a.1#煤样；b.2#煤样；c.3#煤样；d.4#煤样；e.5#煤样

Fig. 3. SEM images of different coal samples

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图 4 小角X射线散射试验站简图

Fig. 4. The system diagram of test station

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图 5 吸附设备实物图

Fig. 5. The design of adsorption equipment

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图 6 大淑村煤样孔径分布

Fig. 6. Pore size distribution of Dashucun coal sample

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图 7 孔隙气体的扩散模式

Fig. 7. Diffusion model of porous gas

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图 8 不同压力、温度条件下Knudsen数随孔径变化

Fig. 8. The change of Knudsen number with pore diameter in different pressures and temperatures

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图 9 温度、压强对Knudsen数的影响

Fig. 9. Effect of temperature and pressure on Knudsen number

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表 1 实验煤样煤质分析结果

Table 1. Coal quality analysis data of experimental coal samples

煤样编号	采样地点	水分含量(%)	干基挥发分(%)	干基灰分(%)	固定碳(%)
1#	润宏3#	2.015	12.510	16.965	73.615
2#	常村3#	0.730	14.670	6.180	78.580
3#	东曲9#	0.460	16.450	7.900	75.310
4#	官地3#	0.820	13.310	11.050	75.480
5#	凤凰山9#	0.915	14.550	7.265	77.600

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表 2 煤样比表面积和孔容及其比例、吸附能

Table 2. Specific surface area & pore volume, size distribution and adsorption energy of coal samples

煤样编号	孔容 (mL·g^-1)	比表面积 (m²·g^-1)	N₂吸附量 (mL·g^-1)	各孔径段孔容比(%)			各孔径段比表面积比(%)			微孔平均孔径(nm)	吸附能 (kJ/mol)
煤样编号	孔容 (mL·g^-1)	比表面积 (m²·g^-1)	N₂吸附量 (mL·g^-1)	< 10 nm	10~30 nm	>30 nm	< 10 nm	10~30 nm	>30 nm	微孔平均孔径(nm)	吸附能 (kJ/mol)
1#	0.002	1.810	1.335	3.830	35.970	60.200	91.940	7.100	0.960	2.389	10.883
2#	0.002	0.580	1.083	3.520	20.930	75.500	89.640	7.390	2.970	2.759	9.425
3#	0.006	2.260	3.962	8.700	23.000	68.300	85.320	10.940	3.740	3.134	8.296
4#	0.002	0.790	1.145	3.620	18.180	78.200	86.660	9.270	4.070	2.677	9.713
5#	0.002	0.620	1.580	1.540	20.190	78.270	79.890	14.230	5.880	2.209	11.770

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