二十烷、蒽和对二丁基环己烷在氧化钙中的吸附和扩散特性

摘要/Abstract

摘要： 在823.15~923.15K的温度范围内，采用蒙特卡洛方法和分子动力学方法研究了二十烷（C₂₀H₄₂）、蒽（C₁₄H₁₀）和对二丁基环己烷（C₁₄H₂₈）在氧化钙5 nm的孔道中的吸附和扩散性能，分析了3种分子在氧化钙孔道中的吸附等温线、分子扩散动力学、概率密度分布和径向分布函数。吸附等温线的分析结果表明：C₁₄H₁₀在氧化钙孔道内的吸附量最大，923.15 K时C₁₄H₂₈吸附量最小，823.15 K时C₂₀H₄₂吸附量最小；C₂₀H₄₂和C₁₄H₁₀为多层吸附，C₁₄H₂₈为单层吸附。分子扩散动力学分析结果表明：C₂₀H₄₂的扩散系数最大，C₁₄H₂₈次之，C₁₄H₁₀最小；扩散性能主要受温度和分子构型影响，根据扩散活化能结果可知，C₁₄H₁₀的扩散受温度影响最大，C₁₄H₂₈次之，C₂₀H₄₂最小。概率密度分布和径向分布函数分析结果表明：C₁₄H₁₀在距离孔道表面0.4，0.7，1.1nm附近存在3个吸附层；C₂₀H₄₂和C₁₄H₂₈的吸附层在距离孔道表面0.5 nm附近的空间中。

关键词: 二十烷, 蒽, 对二丁基环己烷, 氧化钙, 吸附, 扩散, 分子模拟

Abstract: In the temperature range of 823.15-923.15 K, the adsorption and diffusion properties of eicosane (C₂₀H₄₂), anthracene (C₁₄H₁₀) and p-dibutylcyclohexane (C₁₄H₂₈) in 5 nm pore channels of calcium oxide were studied by Monte Carlo and molecular dynamics methods. The adsorption isotherm, molecular diffusion kinetics, probability density distribution and radial distribution function of the three molecules in the calcium oxide pore channels were analyzed. The analysis of adsorption isotherm showed that the adsorption capacity of C₁₄H₁₀ in calcium oxide pore was the highest, the adsorption capacity of C₁₄H₂₈ was the lowest at 923.15 K, and the adsorption capacity of C₂₀H₄₂ was the lowest at 823.15 K; C₂₀H₄₂ and C₁₄H₁₀ were multi-layer adsorption, while C₁₄H₂₈ was mono-layer adsorption. Molecular diffusion dynamics analysis showed that the diffusion coefficient of C₂₀H₄₂ was the largest, followed by that of C₁₄H₂₈, and that of C₁₄H₁₀ was the smallest. The diffusion performance is mainly affected by temperature and molecular configuration. According to the activation energy of diffusion, the diffusion of C₁₄H₁₀ is most affected by temperature, followed by that of C₁₄H₂₈, and that of C₂₀H₄₂ is the smallest. The analysis of probability density distribution and radial distribution function showed that there were three adsorption layers of C₁₄H₁₀ near the surface at distances of 0.4, 0.7 and 1.1 nm, while C₂₀H₄₂ and C₁₄H₂₈ had three adsorption layers at 0.5 nm from the surface.

Key words: eicosane, anthracene, p-dibutylcyclohexane, calcium oxide, adsorption, diffusion, molecular simulation

孙立鹏鲁家荣姜海英赵德明李国梁岳远宁李金明辛德兴闫昊陈小博刘熠斌. 二十烷、蒽和对二丁基环己烷在氧化钙中的吸附和扩散特性[J]. 石油炼制与化工, 2024, 55(10): 32-40.

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