煤田地质与勘探2025，Vol.53Issue(12)：64-77,14.DOI:10.12363/issn.1001-1986.25.05.0409
煤层CO2吸附相密度变化特征及其控制机理
Variation characteristics of CO2 adsorption phase density in coal seam and Its Controlling mechanism:A case study of Huainan-Huaibei coalfield
摘要
Abstract
[Objectives and Methods]The CO2 adsorption phase density is a key factor determining the CO2 adsorption sequestration capacity in coal seams.To deeply understand the characteristics of CO2 density distribution in pores of the coal seam,taking the No.13 coal from Liuzhuang Mine of Huainan mining area and the No.7 coal in Huaibei mining area as the research objects,the CO2 adsorption phase density of at different pressures and temperatures with different dominant pore diameters was simulated through the simplified local density theory(SLD).The CO2 adsorption phase densities were obtained by different methods,the variation characteristics of CO2 adsorption phase density in coal were analyzed,the variation characteristics of the CO2 adsorption phase density in coal and the relationship between the phase state distribution of CO2 in coal and pressure,temperature and pore diameter were discovered,to reveal the contrfol mechanism of CO2 adsorption phase density and point out the further research direction of SLD simulation of CO2 ad-sorption phase density in coal seams.[Results and Conclusions]The results show that:(1)At the same temperature,the density of CO2 in coal pores of the same size increases with pressure.When the pore diameter is≤2.0 nm,the relation-ship between CO2 density at the pore center and pressure follows Langmuir characteristics,and CO2 exists mainly in the adsorbed phase;for pores>2.0 nm,Langmuir fitting does not converge,and free-phase CO2 appears only when the pore center pressure reaches the supercritical level.(2)When the pressure is<8 MPa,the density of CO2 in coal pores de-creases as temperature rises;when the pressure is≥8 MPa and the pore diameter exceeds 3.0 nm,the CO2 density below the critical temperature becomes lower than that above it,and this trend becomes more pronounced with increasing pore size.(3)At a pore diameter of 3.0 nm,free-phase CO2 appears at the pore center,while at>4.0 nm the center is entirely dominated by the free phase.(4)The essence of the temperature-pressure-pore size synergy in controlling CO2 adsorbed-phase density lies in regulating the thickness of the adsorbed layer,thereby affecting its density.(5)This study reveals the synergistic mechanism of temperature,pressure,and pore size on CO2 adsorbed-phase density in coal,provides a the-oretical basis for understanding effective CO2 sequestration,and indicates that future SLD simulations should further consider the effects of heterogeneous pore structures.关键词
CO2吸附相密度/控制机理/SLD模拟/两淮矿区/赋存状态/孔隙非均质性Key words
CO2 adsorption phase density/controlling mechanism/simplified local density(SLD)simulation/Huainan-Huaibei mining area/occurrence state/pore heterogeneity分类
天文与地球科学引用本文复制引用
刘会虎,范正谱,杨靖浩,刘峻麟,丁海,徐宏杰,高德燚,方辉煌,赵雨晴..煤层CO2吸附相密度变化特征及其控制机理[J].煤田地质与勘探,2025,53(12):64-77,14.基金项目
国家自然科学基金项目(42277483,42472228) （42277483,42472228）
2023年安徽省重大基础研究项目(2023z04020001) （2023z04020001）
安徽省公益性地质工作项目(2023-g-1-21,2021-g-2-14) （2023-g-1-21,2021-g-2-14）
