Adsorption Equilibrium of CO2 and CH4 and Their Mixture on Sichuan Basin Shale

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• 作者：Shuo Duan ; Min Gu ; Xidong Du ; Xuefu Xian
• 刊名：Energy & Fuels
• 出版年：2016
• 出版时间：March 17, 2016
• 年：2016
• 卷：30
• 期：3
• 页码：2248-2256
• 全文大小：581K
• ISSN：1520-5029

文摘

Adsorption equilibrium isotherms of CO₂, CH₄, and mixtures of CO₂/CH₄ on shale sampled from Nanchuan, southeastern Sichuan Basin, were measured at 278, 298, and 318 K by an accurate gravimetric method. The adsorption equilibrium data of CO₂ and CH₄ were fitted using both the virial model and the Brunauer–Emmett–Teller (BET) model, and the isotherms of CO₂/CH₄ mixtures were fitted by an extended BET model. On the basis of adsorption data, the adsorption selectivity factors for CO₂ over CH₄ (α_CO2/CH4) and thermodynamic parameters were estimated. Nanchuan shale was characterized with a high total organic carbon (TOC), having inorganic minerals and wide pore size distribution ranges. The adsorption heat, negative Gibbs free energy change, and negative surface potential of CO₂ are larger than those of CH₄, and the entropy loss of CO₂ is larger than that of CH₄, suggesting that adsorbed CO₂ is in a more highly ordered arrangement than CH₄ on shale. α_CO2/CH4 values at different temperatures are all larger than 2.5.