关键词: 低硫柴油, 脂肪酸酯, 润滑性能, 分子模拟

Abstract:

Proper additives for low sulfur diesel are necessary to enhance its lubrication properties. Therefore, appropriate amount of methyl myristate (C₁₄), methyl palmitate (C₁₆), methyl stearate (C₁₈), methyl oleate (C_18:1), methyl linoleate (C_18：2) and methyl ricinoleate (C_18:1OH) were added into diesel fuel. Based on the Materials Studio software, constructions of various fatty acid methyl ester/n-tetradecane mixtures adsorbed on the Fe surface were built up, and then the energy composition of esters contained oil film was analyzed. The results show that for the C₁₄/n-tetradecane mixture, adsorption energies significantly increase with the increase of C₁₄ volume fraction, while cohesive energies differ slightly. For 5% volume fraction of esters/n-tetradecane mixtures， adsorption energies are almost the same, while cohesive energies change with the carbon chain length, the degree of unsaturation and the polar groups in descend order of C_18:1OH, C_18：2, C_18:1, C₁₈, C₁₆, C₁₄. Overall, it is found that the ester fraction has more influence on adsorption energies, while the ester composition has more influence on cohesive energies. In conclusion, both the increase of ester fraction and the change of ester composition are effective ways to improve the lubrication properties of low sulfur diesel fuel.

Key words: low sulfur diesel oil, fatty acid ester, lubrication performance, molecular simulation