分子视角下煤对O_(2)/CH_(4)混合气体的竞争吸附研究  

Study on competitive adsorption of O_(2)/CH_(4) mixed gas by coal from molecular perspective

作　　者：贺姝静 彭程阳 康建宏[1] 张耕显 HE Shujing;PENG Chengyang;KANG Jianhong;ZHANG Gengxian(School of Safety Engineering,China University of Mining and Technology,Xuzhou Jiangsu 221116,China)

机构地区：[1]中国矿业大学安全工程学院,江苏徐州221116

出　　处：《中国安全科学学报》2025年第1期137-145,共9页China Safety Science Journal

基　　金：国家自然科学基金资助(52274240,52227901);江苏高校“青蓝工程”项目(苏教师函〔2021〕11号);江苏省研究生科研创新计划项目(KYCX24_2934);中国矿业大学研究生创新计划项目(2024WLKXJ163)。

摘　　要：为深刻理解煤表面对O_(2)/CH_(4)混合气体的竞争吸附特性,基于巨正则蒙特卡罗法(GCMC)分析煤表面孔隙分布和化学结构;采用分子模拟研究不同浓度、不同压力、不同温度下O_(2)/CH_(4)混合气体竞争吸附过程中的吸附量和吸附热变化特征,并通过吸附选择性揭示O_(2)/CH_(4)混合气体在煤表面的竞争吸附机制。结果表明:O_(2)与CH_(4)浓度比为7/3时,二者的等温吸附曲线接近;不同条件下O_(2)与CH_(4)的积分吸附热相差不大,O_(2)约19.5~20.0 J/g,CH_(4)约24.0~24.8 J/g;当O_(2)与CH_(4)浓度比为7/3~2/8时,O_(2)的积分吸附热大于CH_(4);随着温度升高,O_(2)与CH_(4)的吸附量均减少,且O_(2)对CH_(4)的吸附选择性增大,气体压力对竞争吸附的影响减弱;低气体压力条件下,CH_(4)比O_(2)吸附速率更快,当混合气体总压增加时,CH_(4)比O_(2)先达到饱和吸附;随着混合气体中O_(2)浓度的增加,O_(2)对CH_(4)的吸附选择性呈现降低趋势,但CH_(4)的吸附竞争力始终优先于O_(2)。To deeply understand the competitive adsorption characteristics of O_(2)/CH_(4) gas mixtures on the coal surface,the pore distribution and chemical structure of the coal surface were analyzed using the Grand Canonical Monte Carlo(GCMC)method.Molecular simulation was used to investigate adsorption capacity and heat variations during the competitive adsorption of O_(2)/CH_(4) gas mixtures under varying concentrations,pressures,and temperatures.Moreover,the competitive adsorption mechanism of O_(2)/CH_(4) gas mixtures on the coal surface was revealed by adsorption selectivity.The results indicated that the isothermal adsorption curves were identical when the concentration ratio of O_(2) to CH_(4) was 7/3.The integrated adsorption heat under different conditions was approximately 19.5-20.0 J/g for O_(2) and 24.0-24.8 J/g for CH_(4).When the concentration ratio of O_(2) to CH_(4) ranged between 7/3 and 2/8,the integrated adsorption heat of O_(2) was higher than that of CH_(4).The increased temperature decreased the adsorption capacity of both gases but increased the adsorption selectivity of O_(2) to CH_(4).Moreover,the effect of gas pressure on competitive adsorption weakened with pressure increase.CH_(4) adsorbed faster than O_(2) under low gas pressures,and CH_(4) reached saturation adsorption earlier than O_(2) when the total pressure increased.When the O_(2) concentration in the gas mixtures increased,the adsorption selectivity of O_(2) for CH_(4) decreased.However,CH_(4) consistently showed higher adsorption competitiveness than O_(2).

关 键 词：煤 O_(2)/CH_(4)混合气体 竞争吸附 吸附热 分子模拟 

分 类 号：X936[环境科学与工程—安全科学]