Theoretical insight into the enhanced CH₄ desorption via H₂O adsorption on different rank coal surfaces

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• 作者：Yanan Zhou^a ; ^b ; Wenjing Sun^a ; ^c ; Wei Chu^a ; ^b ; ^{chuwei1965@scu.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Xiaoqiang Liu^b ; Fangli Jing^a ; Ying Xue^b
• 关键词：Coal rank ; Adsorption ; Methane ; ECBM ; Density functional calculations
• 刊名：Journal of Energy Chemistry
• 出版年：2016
• 出版时间：July 2016
• 年：2016
• 卷：25
• 期：4
• 页码：677-682
• 全文大小：1674 K

文摘

The density functional theory was used to investigate the adsorption of CH₄ and H₂O on different rank coal surfaces. The coal rank is the dominant factor in affecting the adsorption capacity of coal. In order to better understand gas and water interaction with coal of different maturity, we developed fourteen coal models to represent the different rank coal. The interactions of CH₄ and H₂O with coal surfaces were studied and characterized by their adsorption energies, Mulliken charges and electrostatic potential surfaces. The results revealed that the interaction between coal and CH₄ was weak physical adsorption, and that the interaction between coal and H₂O consisted of physical and chemical adsorption. Adsorption energy of coal–H₂O system was larger than that of coal–CH₄ on all rank coals, suggesting that the adsorption priority in the coal models is H₂O > CH₄. Consequently, the injection of H₂O into the different rank coal could effectively enhance the coal bed methane (CBM) recovery.