梅德清, 罗演强, 沈学峰, 陆大勇, 袁银男. 脂肪酸甲酯生物柴油改善低硫柴油的润滑性能[J]. 农业工程学报, 2016, 32(9): 193-197. DOI: 10.11975/j.issn.1002-6819.2016.09.027
    引用本文: 梅德清, 罗演强, 沈学峰, 陆大勇, 袁银男. 脂肪酸甲酯生物柴油改善低硫柴油的润滑性能[J]. 农业工程学报, 2016, 32(9): 193-197. DOI: 10.11975/j.issn.1002-6819.2016.09.027
    Mei Deqing, Luo Yanqiang, Shen Xuefeng, Lu Dayong, Yuan Yinnan. Lubrication properties of fatty acid methyl esters as low-sulfur diesel enhancers[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2016, 32(9): 193-197. DOI: 10.11975/j.issn.1002-6819.2016.09.027
    Citation: Mei Deqing, Luo Yanqiang, Shen Xuefeng, Lu Dayong, Yuan Yinnan. Lubrication properties of fatty acid methyl esters as low-sulfur diesel enhancers[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2016, 32(9): 193-197. DOI: 10.11975/j.issn.1002-6819.2016.09.027

    脂肪酸甲酯生物柴油改善低硫柴油的润滑性能

    Lubrication properties of fatty acid methyl esters as low-sulfur diesel enhancers

    • 摘要: 生物柴油可作为改善低硫柴油润滑性能的天然添加剂。该文将豆蔻酸甲酯(C14:0)、棕榈酸甲酯(C16:0)、硬脂酸甲酯(C18:0)、油酸甲酯(C18:1)、亚油酸甲酯(C18:2)、亚麻酸甲酯(C18:3)、蓖麻醇酸甲酯(C18:1 OH)及蓖麻油甲酯和餐饮废油甲酯按照0.5%、1.0%、1.5%和3.0%的体积分数添加到低硫柴油中,在高频往复试验机(high-frequency reciprocating rig,HFRR)上进行润滑性能测试,探究脂肪酸甲酯的碳链长度、不饱和度及含羟基等结构特征对润滑性能的影响。结果表明,长碳链脂肪酸甲酯一般比短链润滑效果好;碳链长度为十八的脂肪酸酯中,不饱和程度即碳碳双键数目越高则润滑性能越好;而在相同碳链长度和不饱和度条件下,含羟基的蓖麻醇酸甲酯的润滑改善效果优于油酸甲酯。由多种脂肪酸酯构成的混合物生物柴油的润滑性能要优于某单一的纯脂肪酸甲酯。在低硫柴油中,当某饱和脂肪酸甲酯的体积分数比例达3.0%时,或不饱和酯的体积分数达到1.5%时,或生物柴油的体积分数达1.0%时,可使低硫柴油的润滑性能指标满足相关标准。研究脂肪酸甲酯的各种结构特征对其润滑性能的影响及作用机制,有助于筛选合适的生物柴油组分及其添加浓度作为低硫柴油的润滑添加剂。

       

      Abstract: Abstract: Increasingly rigorous restriction on the sulfur content in diesel leads to a decrease in fuel lubricity. This reduced lubricity can cause damage to the fuel injection system of an engine. Biodiesel, which is derived from animal fats or vegetable oils by transesterification under alkali or acid catalysts, has been prevailed as an alternative fuel. It has been observed that the fatty acid esters in biodiesel play an active role in enhancing lubricity. Therefore, now biodiesel can serve as an additive to low-sulfur diesel fuel. To correlate the carbon chain length, unsaturation and hydroxylation of the fatty acid methyl ester to its lubricity, methyl myristic (C14:0), methyl palmitic (C16:0), methyl stearate (C18:0), methyl oleate (C18:1), methyl linoleate (C18:2), methyl linolenate (C18:3), methyl ricinoleate (C18:1 OH), castor oil methyl ester and cooking waste oil methyl ester were added to low-sulfur diesel fuel by 0.5%, 1.0%, 1.5% and 3.0%, respectively. Two types of biodiesel from castor oil and cooking waste oil, representing the mixtures of multiple fatty acid methyl esters, were also added to diesel fuel for wear test. The specified components of the two mixture solutions were determined by GC-MS. The low-sulfur diesel used in the test was manufactured by a hydrogenation process. The lubricity of various samples was studied using a high frequency reciprocating rig (HFRR) analysis method. Each wear test was repeated three times to minimize the error. As for methyl myristic (C14:0), methyl palmitic (C16:0) and methyl stearate (C18:0), we found that the fatty acid methyl ester with longer carbon chain had a better lubricity. For the C18 series, such as methyl stearate (C18:0), methyl oleate (C18:1), methyl linoleate (C18:2) and methyl linolenate (C18:3), an enhancement in lubricity was observed with the increase in the unsaturation degree of esters. Although with the same carbon chain length and unsaturation, methyl ricinoleate (C18:1 OH), as a hydroxylated ester, had better lubricity than methyl oleate (C18:1) compared with other treatments. Meanwhile, the individual fatty acid methyl ester did not show remarkable lubricating performance as biodiesel which was composed of several esters as a mixture. Biodiesel can perform better with more hydroxylated esters. From the wear test results, the lubricity of low-sulfur diesel can meet the requirement of the national standard with the addition ratio of saturated fatty acid methyl esters, unsaturated fatty acid methyl esters and biodiesel reaching 3.0%, 1.5% and 1.0%, respectively. In all, we concluded that there was a high correlation between lubricating properties with the unsaturation degree and hydroxyl groups in ester molecules. Studying the effects of molecule structure of fatty acid esters on the lubricating properties and its operation mechanism will be greatly beneficial for choosing the suitable biodiesel components as the lubricity enhancers in low-sulfur diesel.

       

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