Research on a modified model for adsorption of methane on coal under temperature effect considering excess adsorption

doi:10.16265/j.cnki.issn1003-3033.2018.10.023

Abstract

Abstract: In order to study the adsorption characteristics of coal in deep mining, isothermal adsorption of methane on coal experiments were carried out at different temperatures by using an isothermal adsorption device. Based on the theory of adsorption heat, an adsorption model considering the correction of temperature and excess adsorption(the modified L-F model) was built, and its effectiveness was verified by comparing the experimental results with the predicted by the model. The results show that the adsorption of methane on coal is a physical adsorption process, an exothermic reaction, that the adsorption heat decreases with the increase of adsorption volume, that the methane excess adsorption on coal is a none-linear function of methane pressure, that the methane adsorption volume gradually decreases with increasing temperature, and that compared with the conventional adsorption models(L and dual-site L model), the modified L-F model fits the experimental data and can better predict the methane adsorption volume on coal at different temperatures.

Key words: coal, temperature, methane pressure, excess adsorption, adsorption model

CLC Number:

X936

YANG Kang, LI Bobo, REN Chonghong, LI Jianhua, XU Jiang, YUAN Mei. Research on a modified model for adsorption of methane on coal under temperature effect considering excess adsorption[J]. China Safety Science Journal, 2018, 28(10): 137-142.

References

[1] 宋昱, 姜波, 李明, 等. 低中煤级构造煤超临界甲烷吸附特性及吸附模型适用性[J]. 煤炭学报, 2017, 42(8): 2 063-2 073.
SONG Yu, JIANG Bo, LI Ming, et al. Super critical CH₄ adsorption characteristics and applicability of adsorption models for low, middle-rank tectonically deformed coals[J]. Journal of China Coal Society, 2017, 42(8): 2 063-2 073.
[2] 李波波, 杨康, 徐鹏, 等. 力热耦合条件下煤岩渗透率模型研究[J]. 中国安全科学学报, 2017, 27(6): 139-144.
LI Bobo, YANG Kang, XU Peng, et al. Research on model for permeability of coal under stress and temperature coupling condition[J]. China Safety Science Journal, 2017, 27(6): 139-144.
[3] 李松, 汤达祯, 许浩, 等. 深部煤层气储层地质研究进展[J].地学前缘, 2016, 23(3): 10-16.
LI Song, TANG Dazhen, XU Hao, et al. Progress in geological researches on the deep coalbed methane reservoirs[J].Earth Science Frontiers, 2016, 23(3): 10-16.
[4] 杨兆彪, 秦勇, 高弟, 等. 超临界条件下煤层甲烷视吸附量、真实吸附量的差异及其地质意义[J]. 天然气工业, 2011, 31(4): 13-16.
YANG Zhaobiao, QIN Yong, GAO Di, et al. Differences between apparent and true adsorption quantity of coalbed methane under supercritical conditions and their geological significance[J]. Natural Gas Industry, 2011, 31(4): 13-16.
[5] 周来, 冯启言, 秦勇. CO₂和CH₄在煤基质表面竞争吸附的热力学分析[J]. 煤炭学报, 2011, 36(8): 1 307-1 311.
ZHOU Lai, FENG Qiyan, QIN Yong. Thermodynamic analysis of competitive adsorption of CO₂ and CH₄ on coal matrix[J]. Journal of China Coal Society, 2011, 36(8): 1 307-1 311.
[6] FIANU J, GHOLINEZHAD J, HASSAN M. Comparison of temperature-dependent gas adsorption models and their application to shale gas reservoirs[J]. Energy & Fuels, 2018, 32(4): 4 763-4 771.
[7] TANG Xu, RIPEPI N, STADIE N P, et al. A dual-site Langmuir equation for accurate estimation of high pressure deep shale gas resources[J]. Fuel, 2016, 185: 10-17.
[8] 郇璇, 张小兵, 韦欢文. 基于不同类型煤吸附甲烷的吸附势重要参数探讨[J]. 煤炭学报, 2015, 40(8): 1 859-1 864.
HUAN Xuan, ZHANG Xiaobing, WEI Huanwen. Research on parameters of adsorption potential via methane adsorptionof different types of coal[J]. Journal of China Coal Society, 2015, 40(8): 1 859-1 864.
[9] 杨峰, 宁正福, 张睿,等. 甲烷在页岩上的吸附等温过程[J]. 煤炭学报, 2014, 39(7): 1 327-1 332.
YANG Feng, NING Zhengfu, ZHANG Rui, et al. Adsorption isotherms process of methane on gas shales[J]. Journal of China Coal Society, 2014, 39(7): 1 327-1 332.
[10] MYERS A L. Thermodynamics of adsorption in porous materials[J]. Aiche Journal, 2002, 48(1): 145-160.
[11] OZAWA S, KUSUMI S, OGINO Y. Physical adsorption of gases at high pressure. IV. An improvement of the Dubinin Astakhov adsorption equation[J]. Journal of Colloid & Interface Science, 1976, 56(1): 83-91.
[12] COCHRAN T W, KABEL R L, DANNER R P. Vacancy solution theory of adsorption using Flory-Huggins activity coefficient equations[J]. Aiche Journal, 2010, 31(2): 268-277.
[13] ZHOU Li, ZHANG Junshe, ZHOU Yaping. A simple isotherm equation for modeling the adsorption equilibria on porous solids over wide temperature rangest[J]. Langmuir, 2001, 17(18): 1 158-1 169.
[14] 周军平,鲜学福,李晓红,等. 吸附不同气体对煤岩渗透特性的影响[J]. 岩石力学与工程学报,2010,29(11): 2 256-2 262.
ZHOU Junping, XIAN Xuefu, LI Xiaohong, et al. Effect of different adsorptional gases on permeability of coal[J]. Chinese Journal of Rock Mechanics and Engineering, 2010, 29(11): 2 256-2 262.
[15] XING Wanli, SONG Yongchen, ZHANG Yi, et al. Adsorption isotherms and kinetic characteristics of methane on block anthracite over a wide pressure range[J]. Journal of Energy Chemistry, 2015, 24(2): 245-256.