CO₂/N₂在不同挥发分烟煤中的吸附特性研究

Study on Adsorption Characteristics of CO₂/N₂ in Bituminous Coal with Different Volatile Contents

摘要: 为研究CO₂、N₂在不同挥发分烟煤中的吸附特性，本文对煤LL (C₁₈₆H₁₅₃NO₆)、煤PDS-1 (C₂₀₇H₁₆₅NO₁₁)和煤XZ (C₁₈₁H₁₆₃NO₆)在不同温度和不同压力下进行了巨正则蒙特卡洛模拟和分子动力学模拟。结果表明，CO₂在不同挥发分烟煤分子中的吸附量和吸附速率大于N₂吸附量，在低挥发分烟煤中极限吸附量最大，且随着挥发分程度升高而降低；两种气体的吸附热都小于40 kJ/mol，并且对于压力和温度的变化不敏感。另外，CO₂和N₂更容易吸附在含氧官能团和苯环附近。CO₂和N₂在煤中的扩散能力为N₂ > CO₂，这是由于CO₂具有更强的吸附能力。

Abstract: In order to study the adsorption characteristics of CO₂ and N₂ in bituminous coals with different volatiles, giant canonical Monte Carlo simulation and molecular dynamics simulation were performed on coal LL (C₁₈₆H₁₅₃NO₆), coal PDS-1 (C₂₀₇H₁₆₅NO₁₁) and coal XZ (C₁₈₁H₁₆₃NO₆) at different temperatures and pressures in this paper. The results show that the adsorption amount and rate of CO₂ in different volatile bituminous coal molecules are greater than that of N₂, and the limit adsorption amount of CO₂ in low-volatile bituminous coal is the largest and decreases with the increase of volatile content; the adsorption heat of the two gases are less than 40 kJ/mol and are not sensitive to changes in pressure and temperature. In addition, CO₂ and N₂ are more eas-ily adsorbed near oxygen-containing functional groups and benzene rings. The order of diffusivity of CO₂ and N₂ in coal is N₂> CO₂, which is due to the stronger adsorption capacity of CO₂.