Aging analysis of alternative fuels and biofuels in a novel test rig. (April 2023) - Duchowny, Anton
Abstract: Understanding aging phenomena of alternative fuels, such as fatty acid methyl esters (FAME), hydrogenated vegetable oil, or synthetic power-to-X products, has become a highly active research field since their introduction led to different aging-related phenomena. More alternative fuels lead to ever more fuel blend varieties that all need to undergo a usability assessment, implying plenty fuel aging experiments. Laboratory tests usually artificially age fuels at high temperatures to examine aging products. However, in this work, a novel test rig was designed to closely simulate the conditions encountered in practice. This way, knowledge gain and innovation can be achieved for fuel aging and concerning hardware and additive technology to decrease deposit buildup. Results from pure FAME revealed a discrepancy, in which it failed conventional fuel aging tests but performed well in this realistic setup due to the fuel's high polarity preventing deposit accumulation. Among the standardized fuel tests, thermal, spectroscopic, and chromatographic techniques used in this work, benchtop 1 H Nuclear Magnetic Resonance (NMR) spectroscopy delivered insightful information with minimal effort and sample volume. The examined deposits mainly consist of (oxidized) FAME species (≈70%) interacting with aromatic compounds (≈5.5%). Moreover, only blends of conventional fuel and FAME lead to system failures and large quantities of deposits. Graphical abstract: Image 1 Highlights: Novel test rig for fuel aging and additive performance analysis. Petro-based fuel, FAME, HVO, a power-to-liquid product, and blends were examined. Analytical methods were standard tests, TGA, DSC, NMR, IR, 2D-GC-MS. Benchtop NMR spectroscopy found to be an easy-to-use and rapid analytical tool. FAME in combination with aromatics lead to tacky deposits causing system failures.