| Citation: |
QIN Yujin，AN Fenghua，SU Weiwei，et al. Direct determination of the diffusion coefficient variation of coal based on Fick's law and model establishment[J]. Coal Science and Technology，2023，51（8）：140−149. DOI: 10.13199/j.cnki.cst.2022-0966
|
Gas diffusion ability directly affects gas exploitation, outburst risk, emission and content determination. In order to study the influence of stress, gas pressure and temperature on gas diffusion coefficient in coal, the gas diffusion coefficient in columnar coal sample was measured with stable concentration difference, which avoided the model dependence that caused by deducing diffusion coefficient through desorption curve. The experimental results shown that the diffusion coefficient was approximately negative linear related to the effective stress for both the adsorbed methane and the non-adsorbed helium, but it was less affected than the permeability. The methane diffusion coefficient decreased as a power function with increasing inlet pressure (concentration gradient), and the relationship with temperature satisfied the Arrhenius formula. The diffusion coefficient measured by the steady-state method was compared with those obtained by the classical model and the time-varying model. It was found that the obtained diffusion coefficients were of the same order of magnitude, the sizes can be several times different, and the variation trend of diffusion coefficient was different with increasing gas pressure. Based on the law of diffusion coefficient affected by pressure (concentration) and temperature, a variable diffusion coefficient model was established. The gas desorption for granular coal at constant and variable temperature was predicted utilizing measured diffusion coefficient for columnar coal, and the prediction results were validated by desorption test. It indicated that the model can well reflect the gas diffusion process in the coal matrix under both constant and variable temperature condition.
| [1] |
林柏泉,刘 厅,杨 威. 基于动态扩散的煤层多场耦合模型建立及应用[J]. 中国矿业大学学报,2018,47(1):32−39,112.
LIN Baiquan,LIU Ting,YANG Wei. Solid-gas coupling model for coalseams based on dynamic diffusion and its application[J]. Journal of China University of Mining & Technology,2018,47(1):32−39,112.
|
| [2] |
杨宏民,冯朝阳,陈立伟. 煤层注氮模拟实验中的置换−驱替效应及其转化机制分析[J]. 煤炭学报,2016,41(9):2246−2250.
YANG Hongmin,FENG Zhaoyang,CHEN Liwei. Analysis of replacement-displacement effect and its change mechanism in simulation experiment of nitrogen injection into coal seam[J]. Journal of China Coal Society,2016,41(9):2246−2250.
|
| [3] |
胡国忠,朱怡然,李志强. 可控源微波场促进煤体中甲烷解吸的试验研究[J]. 岩石力学与工程学报,2017,36(4):874−880.
HU Guozhong,ZHU Yiran,LI Zhiqiang. Experimental study on desorption enhancing of methane in coal mass using a controlled microwave field[J]. Chinese Journal of Rock Mechanics and Engineering,2017,36(4):874−880.
|
| [4] |
杨新乐,张永利. 热采煤层气藏过程煤层气运移规律的数值模拟[J]. 中国矿业大学学报,2011,40(1):89−94.
YANG Xinle,ZHANG Yongli. Numerical simulation on flow rules of coal-bed methane by thermal stimulation[J]. Journal of China University of Mining & Technology,2011,40(1):89−94.
|
| [5] |
梁卫国,吴 迪,赵阳升. CO2驱替煤层CH4试验研究[J]. 岩石力学与工程学报,2010,29(4):24−32.
LIANG Weiguo,WU Di,ZHAO Yangsheng. Experimental study of coalbeds methane replacement by carbon dioxide[J]. Chinese Journal of Rock Mechanics and Engineering,2010,29(4):24−32.
|
| [6] |
刘彦伟,刘明举. 粒度对软硬煤粒瓦斯解吸扩散差异性的影响[J]. 煤炭学报,2015,40(3):97−105.
LIU Yanwei,LIU Mingju. Effect of particle size on difference of gas desorption and diffusion between soft coal and hard coal[J]. Journal of China Coal Society,2015,40(3):97−105.
|
| [7] |
安丰华,贾宏福,刘 军. 基于煤孔隙构成的瓦斯扩散模型研究[J]. 岩石力学与工程学报,2021,40(5):987−996.
AN Fenghua,JIA Hongfu,LIU Jun. A gas diffusion model based on the pore structure in coal[J]. Chinese Journal of Rock Mechanics and Engineering,2021,40(5):987−996.
|
| [8] |
李祥春,李忠备,张 良,等. 不同煤阶煤样孔隙结构表征及其对瓦斯解吸扩散的影响[J]. 煤炭学报,2019,44(S1):142−156.
LI Xiangchun,LI Zhongbei,ZHANG Liang,et al. Pore structure characterization of various rank coals and its effect on gas desorption and diffusion[J]. Journal of China Coal Society,2019,44(S1):142−156.
|
| [9] |
聂百胜,柳先锋,郭建华,等. 水分对煤体瓦斯解吸扩散的影响[J]. 中国矿业大学学报,2015,44(5):781−787.
NIE Baisheng,LIU Xianfeng,GUO Jianhua,et al. Effect of moisture on gas desorption and diffusion in coal mass[J]. Journal of China University of Mining & Technology,2015,44(5):781−787.
|
| [10] |
李志强, 王登科, 宋党育. 新扩散模型下温度对煤粒瓦斯动态扩散系数的影响 [J]. 煤炭学报, 2015, 40(5): 1055−1064.
LI Zhiqiang, WANG Dengke, SONG Dangyu. Influence of temperature on dynamic diffusion coefficient of CH4 into coal particles by new diffusion model [J]. Journal of China Coal Society, 2015, 40(5): 1055−1064.
|
| [11] |
杨 鑫,张俊英,王公达,等. 瓦斯压力对瓦斯在煤中扩散影响的实验研究[J]. 中国矿业大学学报,2019,48(3):503−510.
YANG Xin,ZHANG Junying,WANG Gongda,et al. Experimental study of the influence of gas pressure in the gas diffusion in coal[J]. Journal of China University of Mining & Technology,2019,48(3):503−510.
|
| [12] |
张登峰,崔永君,李松庚,等. 甲烷及二氧化碳在不同煤阶煤内部的吸附扩散行为[J]. 煤炭学报,2011,36(10):1693−1698.
ZHANG Dengfeng,CUI Yongjun,LI Songgeng,et al. Adsorption and diffusion behaviors of methane and carbon dioxide on various rank coals[J]. Journal of China Coal Society,2011,36(10):1693−1698.
|
| [13] |
CHENG Y,PAN Z. Reservoir properties of Chinese tectonic coal: A review[J]. Fuel,2020,260:116350. doi: 10.1016/j.fuel.2019.116350
|
| [14] |
ZHAO W,CHENG Y,PAN Z,et al. Gas diffusion in coal particles: A review of mathematical models and their applications[J]. Fuel,2019,252:77−100. doi: 10.1016/j.fuel.2019.04.065
|
| [15] |
杨其銮,王佑安. 煤屑瓦斯扩散理论及其应用[J]. 煤炭学报,1986,11(3):87−94.
YANG Qiluan,WANG Youan. Theory and application of gas diffusion in coal particles[J]. Journal of China Coal Society,1986,11(3):87−94.
|
| [16] |
聂百胜,郭勇义,吴世跃,等. 煤粒瓦斯扩散的理论模型及其解析解[J]. 中国矿业大学学报,2001,30(1):21−24.
NIE Baisheng,GUO Yongyi,WU Shiyue,et al. Theoretical of methane diffusion from coal cuttings and its application[J]. Journal of China University of Mining & Technology,2001,30(1):21−24.
|
| [17] |
简 星,关 平,张 巍. 煤中 CO2的吸附和扩散: 实验与建模[J]. 中国科学:地球科学,2012,42(4):492−504.
JIAN Xing,GUAN Ping,ZHANG Wei. Carbon dioxide sorption and diffusion in coals: Experimental investigation and modeling[J]. Science China Earth Science,2012,42(4):492−504.
|
| [18] |
WANG K,WANG Y,GUO H,et al. Modelling of multiple gas transport mechanisms through coal particle considering thermal effects[J]. Fuel,2021,295:120587. doi: 10.1016/j.fuel.2021.120587
|
| [19] |
SAMPATH K H S M,PERERA M S A,MATTHAI S K,et al. Modelling of fully-coupled CO2 diffusion and adsorption-induced coal matrix swelling[J]. Fuel,2020,262:116486. doi: 10.1016/j.fuel.2019.116486
|
| [20] |
LIU A,LIU S,HOU X,et al. Transient gas diffusivity evaluation and modeling for methane and helium in coal[J]. International Journal of Heat and Mass Transfer,2020,159:120091. doi: 10.1016/j.ijheatmasstransfer.2020.120091
|
| [21] |
SHI J,DURUCAN S. A bidisperse pore diffusion model for methane displacement desorption in coal by CO2 injection[J]. Fuel,2003,82(10):1219−1229. doi: 10.1016/S0016-2361(03)00010-3
|
| [22] |
靳钟铭,赵阳升,贺 军,等. 含瓦斯煤层力学特性的实验研究[J]. 岩石力学与工程学报,1991,10(3):271−280.
JIN Zhongming,ZHAO Yangsheng,HE Jun,et al. An experimental study on mechanical properties of gas-bearing coal seams[J]. Chinese Journal of Rock Mechanics and Engineering,1991,10(3):271−280.
|
| [23] |
周军平,鲜学福,姜永东,等. 基于热力学方法的煤岩吸附变形模型[J]. 煤炭学报,2011,36(3):468−472.
ZHOU Junping,XIAN Xuefu,JIANG Yongdong,et al. A model of adsorption induced coal deformation based on thermodynamics approach[J]. Journal of China Coal Society,2011,36(3):468−472.
|
| [24] |
李晓泉,尹光志. 含瓦斯煤的有效体积应力与渗透率关系[J]. 重庆大学学报(自然科学版),2011,34(8):103−108.
LI Xiaoquan,YIN Guangzhi. Relationship between effective volumetric stress and permeability of gas-filled coal[J]. Journal of Chongqing University (Natural Science Edition),2011,34(8):103−108.
|
| [25] |
聂百胜,杨 涛,李祥春,等. 煤粒瓦斯解吸扩散规律实验[J]. 中国矿业大学学报,2013,42(6):975−981. doi: 10.3969/j.issn.1000-1964.2013.06.014
NIE Baisheng,YANG Tao,LI Xiangchun,et al. Research on diffusion of methane in coal particles[J]. Journal of China University of Mining & Technology,2013,42(6):975−981. doi: 10.3969/j.issn.1000-1964.2013.06.014
|
| [26] |
LIU T,LIN B,FU X,et al. Experimental study on gas diffusion dynamics in fractured coal: A better understanding of gas migration in in-situ coal seam[J]. Energy,2020,195:117005. doi: 10.1016/j.energy.2020.117005
|
| [27] |
LIU A,LIU P,LIU S. Gas diffusion coefficient estimation of coal: A dimensionless numerical method and its experimental validation[J]. International Journal of Heat and Mass Transfer,2020,162:120336. doi: 10.1016/j.ijheatmasstransfer.2020.120336
|
| [28] |
ZHANG X,ZHU Z,WEN G,et al. Study on gas desorption and diffusion kinetic behavior in coal matrix using a modified shrinking core model[J]. Journal of Petroleum Science and Engineering,2021,204:108701. doi: 10.1016/j.petrol.2021.108701
|
| [29] |
TANG X,LI Z,RIPEPI N,et al. Temperature-dependent diffusion process of methane through dry crushed coal[J]. Journal of Natural Gas Science and Engineering,2015,22:609−617. doi: 10.1016/j.jngse.2014.12.022
|
| [30] |
XU H,TANG D,ZHAO J,et al. A new laboratory method for accurate measurement of the methane diffusion coefficient and its influencing factors in the coal matrix[J]. Fuel,2015,158:239−247. doi: 10.1016/j.fuel.2015.05.046
|
| [31] |
MENG Y,LI Z. Experimental study on diffusion property of methane gas in coal and its influencing factors[J]. Fuel,2016,185:219−228. doi: 10.1016/j.fuel.2016.07.119
|
| [32] |
滕 腾,王 伟,师 访,等. 温度−压力耦合下原煤中CO2渗流行为试验研究[J]. 中国矿业大学学报,2019,48(4):760−767.
TENG Teng,WANG Wei,SHI Fan,et al. Experimental study of the seepage behavior of CO2 in raw coal under coupled pressures & temperature condition[J]. Journal of China University of Mining & Technology,2019,48(4):760−767.
|
| [33] |
荣腾龙,周宏伟,王路军,等. 采掘扰动与温度耦合影响下工作面前方煤体渗透率模型研究[J]. 岩土力学,2019,40(11):4289−4298.
RONG Tenglong,ZHOU Hongwei,WANG Lujun,et al. Study on coal permeability model in front of working face under the influence of mining disturbance and temperature coupling[J]. Rock and Soil Mechanics,2019,40(11):4289−4298.
|
Supported by: Beijing Renhe Information Technology Co., Ltd. 
DownLoad: