Investigation of methane diffusion in low-rank coals by a multiporous diffusion model

doi:10.1016/j.jngse.2016.05.012

IOCAS-IR > 海洋环流与波动重点实验室

	Investigation of methane diffusion in low-rank coals by a multiporous diffusion model
	Li, Zhentao 1; Liu, Dameng 1; Cai, Yidong 1; Shi, Yunlong2
	2016-07-01
发表期刊	JOURNAL OF NATURAL GAS SCIENCE AND ENGINEERING
卷号	33 页码:97-107
文章类型	Article
摘要	To study the methane diffusion behaviors of low-rank coals (R-o,R-m of 0.45% and 0.58%), a combination of CO2 adsorption, N-2 adsorption/desorption, and mercury intrusion porosimetry (MIP) measurements were used to characterize the pore structure of coals, and a new multiporous diffusion model was established to model methane diffusion under dry and moist conditions during the methane adsorption process. The results indicate that the pore structure of low-rank coal samples exhibits a multimodal pore size/volume distribution and has a greater percentage of microporosity and mesoporosity. The multi porous model provides a better fit than the bidisperse model, which deviates significantly from the data, especially during the initial diffusion stage. Based on the multiporous diffusion model, the macropore diffusivity (10(-4)-10(-3) s(-1)) is generally one to three orders of magnitude greater than the mesopore diffusivity (10(-5)-10(-4) s(-1)) and micropore diffusivity (10(-6)-10(-5) s(-1)). Moreover, both the macropore diffusivity and micropore diffusivity show a decreasing trend with increasing pressure, whereas a strong positive correlation exists between the mesopore diffusivities and pressure, indicating that the effect of pressure on methane diffusion in pores with different sizes is different during the adsorption process. This difference may be due to the competition between the different mechanisms of gaseous methane diffusion and the swelling of the coal matrix caused by gas adsorption. Furthermore, the moisture reduced methane diffusivities is mainly due to the moisture in the coal matrix that adsorbs to the pore surface and occupies the pore space, as well as changes the pore structure according to the, effect of mineral swelling from the adsorbing moisture. Therefore, these results may have a significant implication for understanding the transport mechanism of methane in coals and the design of enhanced CBM recovery. (C) 2016 Elsevier B.V. All rights reserved.
关键词	Gas Diffusion Multiporous Diffusion Model Pore Structure Pressure Moisture Content
DOI	10.1016/j.jngse.2016.05.012
收录类别	SCI
语种	英语
WOS记录号	WOS:000381594000011
引用统计	被引频次：60[WOS] [WOS记录] [WOS相关记录]
文献类型	期刊论文
版本	出版稿
条目标识符	http://ir.qdio.ac.cn/handle/337002/135881
专题	海洋环流与波动重点实验室
作者单位	1.China Univ Geosci, Coal Reservoir Lab, Natl Engn Res Ctr, CBM Dev & Utilizat, Beijing 100083, Peoples R China 2.Chinese Acad Sci, Inst Oceanol, Key Lab Ocean Circulat & Waves, Qingdao 266071, Peoples R China
推荐引用方式 GB/T 7714	Li, Zhentao,Liu, Dameng,Cai, Yidong,et al. Investigation of methane diffusion in low-rank coals by a multiporous diffusion model[J]. JOURNAL OF NATURAL GAS SCIENCE AND ENGINEERING,2016,33:97-107.
APA	Li, Zhentao,Liu, Dameng,Cai, Yidong,&Shi, Yunlong.(2016).Investigation of methane diffusion in low-rank coals by a multiporous diffusion model.JOURNAL OF NATURAL GAS SCIENCE AND ENGINEERING,33,97-107.
MLA	Li, Zhentao,et al."Investigation of methane diffusion in low-rank coals by a multiporous diffusion model".JOURNAL OF NATURAL GAS SCIENCE AND ENGINEERING 33(2016):97-107.

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