A novel application of chemically modified eleostearic acid methyl ester (EAME) for improving diesel lubricity

Authors: Liu, Zengshe - Kevin; LI, JING - Chinese Academy Of Forestry; KNOTHE, GERHARD - Former ARS Employee; SHARMA, BRAJENDRA - University Of Illinois; JIANG, JIANGCHUNG - Chinese Academy Of Forestry

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 2/10/2023
Publication Date: 12/22/2023
Citation: Liu, Z., Li, J., Knothe, G.H., Sharma, B.K., Jiang, J. 2023. A novel application of chemically modified eleostearic acid methyl ester (EAME) for improving diesel lubricity. In: Liu, Z., Kraus, G., editors. Green Materials and Green Materials from Plant Oils and Natural Acids. Vol. 83. London, UK:Royal Society of Chemistry. p. 159-169.
DOI: https://doi.org/10.1039/9781837671595

Interpretive Summary: We discovered that tung oil based compounds at low additive levels (about 500 ppm) significantly improved the lubricity of diesels. Use of ultralow-sulfur diesel (ULSD) fuels, as required by regulations in the United States, Europe, and elsewhere, has led to the failure of diesel engine parts such as fuel injectors and pumps. Therefore ULSD requires additives or blending with another material of sufficient lubricity which increases the cost. Adding low level of 500 ppm to the ULSD fuel decreased wear scar and friction by 40-47%, respectively. The additive concentrations are 20 and 40 times lower than blending biodiesel at 1-2% which will benefit the industry.

Technical Abstract: Diesel fuel lubricity has been a concern of diesel fuel injection equipment manufacturers for many years. The problem has drawn recent attention because of the reduction in lubricity associated with the extreme hydrogenation needed to reach the low sulfur levels required in modern diesel fuels. Ultra-low-sulfur diesel (ULSD) fuels require additives or blending with another material of sufficient lubricity, thereby increasing the cost by adding higher concentrations of additives or by blending with other materials. The tung oil based fatty acid methyl ester (eleostearic acid methyl ester, EAME) and the maleation compound (EAME/MA) by reacting with maleic anhydride (MA) via the Diels–Alder reaction were synthesized. The EAME/MA further reacts with short chain alcohols by opening cyclic anhydride to form esters such as methanol and butanol, i.e., EAME/MA/ME and EAME/MA/BU. The EAMA/MA/ME and EAME/MA/BU compounds effectively enhanced the lubricity of ULSD. For example, the lubricity of ULSD at low additive levels (500-1000 ppm) resulted in great improvement in the high-frequency reciprocating rig (HFRR) lubricity tests. By adding low additive level of 500 ppm to the ULSD fuel, the wear scar and friction of ULSD was reduced by 40% and 46-47%, respectively. The additive concentrations were 20 and 40 times lower than blending biodiesel at 1-2%. Also, by blending EAME/MA/BU at a level of 1000ppm into petrodiesels, such as 0150H GP1 Base Oil and 166 POA, wear scar values were reduced by 25% and 26%, respectively.