成果归属机构：

工程技术学院

作者：

Liu, Ang ; Liu, Shimin ; Zhang, Kunming ; Xia, Kaiwen

单位：

Penn State Univ, Ctr G3, Dept Energy & Mineral Engn, University Pk, PA 16802 USA;Penn State Univ, Energy Inst, University Pk, PA 16802 USA;State Key Lab Intelligent Construct & Hlth Operat, Shenzhen 518000, Peoples R China;China Univ Geosci Beijing, Inst Geosafety, Sch Engn & Technol, Beijing 100083, Peoples R China;Tianjin Univ, State Key Lab Hydraul Engn Intelligent Construct &, Tianjin 300072, Peoples R China

关键词：

HIGH-PRESSURE ADSORPTION; ARGONNE PREMIUM COALS; BINARY GAS; METHANE ADSORPTION; DIOXIDE; MIXTURES; DRY; MOISTURE; SELECTIVITY; SIMULATION

摘要：

Geological carbon storage, particularly within coal seams, is recognized as a viable strategy for achieving netzero emissions. However, following CO2 injection into the coal seam, limited studies have addressed the competitive sorption dynamics of CH4 and CO2 on coal, despite the natural presence of CH4 in these formations. In this work, sorption experiments were conducted using two types of coal: sub-bituminous coal and anthracite. Initially, pure CH4 and CO2 gases were employed to conduct individual sorption tests. Subsequently, the competitive sorption of CH4 and CO2 was evaluated using pre-mixed binary gas mixtures with varying CH4/CO2 ratios. Further, the displacement effect of CO2 on CH4 was investigated by injecting CO2 into coal samples that had been pre-adsorbed with CH4. The data reveal that, for both coals, the ideal selectivity calculated from pure gas measurements underestimates the corresponding values from real multicomponent systems. Anthracite demonstrates a higher selectivity for CO2 over CH4 during both adsorption and desorption processes when compared to the ideal selectivity calculated from pure gas sorption data. Conversely, the sub-bituminous coal initially shows lower selectivity for CO2 than for CH4 during adsorption, but this trend reverses and intensifies during desorption. If competitive sorption effects are neglected, coal selectivity for CO2 over CH4 under the examined conditions would be underestimated by a factor of 1.5 to 2.5. Due to the competitive sorption effects between CH4 and CO2, the Langmuir equilibrium constants for gas mixtures are influenced by compositional changes, leading to dynamic deviations from those observed under pure gas conditions. This finding contrasts with the traditional extended Langmuir model, which presumes that the equilibrium constants remain unchanged regardless of gas composition. In addition, the displacement study underscores the efficacy of CO2 in displacing CH4, with higher CO2 ratios intensifying displacement effects. The study highlights the substantial impact of real multicomponent scenarios on coal selectivity for CO2 and CH4, offering deeper insights into predicting competitive sorption behavior between CO2 and CH4 during CO2-enhanced coalbed methane recovery and carbon storage processes.

基金：

State Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering, China [SDGZK2418]; State Key Laboratory of Hydraulic Engineering Intelligent Construction and Operation, Tianjin University [HESS-2409]; National Natural Science Foundation of China [42141010]

语种：

英文

DOI：

10.1016/j.seppur.2024.129399

来源：

SEPARATION AND PURIFICATION TECHNOLOGY,2025():.

出版日期：

2025-02-19

提交日期：

2024-09-24

引用参考：

Liu, Ang; Liu, Shimin; Zhang, Kunming; Xia, Kaiwen. Competitive sorption of CH4 and CO2 on coals: Implications for carbon geo-storage[J]. SEPARATION AND PURIFICATION TECHNOLOGY,2025():.