Talus, A., Johansson, L., Regali, F., and Saramat, A., "Preparation and Characterization of a Stable Test Fuel Comparable to Aged Biodiesel for Use in Accelerated Corrosion Studies," SAE Int. J. Fuels Lubr. 7(3):861-868, 2014, doi:10.4271/2014-01-2772.
Biodiesel is chemically unstable and sensitive to oxidation. Aging of biodiesel results in the formation of degradation products, such as short chain fatty acids (SCFA) and water. These products may cause corrosion of metals in fuel systems. When performing corrosion tests, biodiesel continuously degrades during the test, resulting in an uncontrolled test system. In order to obtain a stable corrosion testing system, a test fuel was developed using a saturated FAME (methyl myristate), which was doped with RME degradation products at levels typically seen in field tests. The test fuel was compared to RME with regards to structure, SCFA and water content before and after aging tests.In addition, an accelerated corrosion study of copper was performed in both the test fuel and in RME. The copper specimens were analyzed before and after test using light optical microscope and weight measurements. The Cu content in the test fuel and RME was also analyzed.The results show that the proposed test fuel is chemically stable and satisfies the targeted acceptance criteria of solubility of degradation products and oxidation stability. The corrosion behavior of copper in the test fuel shows similarities regarding corrosion products and deposits formed compared to copper corrosion in RME.The proposed test fuel enables laboratory tests where parameters affecting corrosion can be kept constant and studied separately. This allows for the development of methods for screening corrosion properties of components and materials in the fuel system.