Article pubs.acs.org/EF
Oxidation of Neat Synthetic Paraffinic Kerosene Fuel and Fuel Surrogates: Quantitation of Dihydrofuranones Renée L. Webster,†,‡ David J. Evans,*,† Paul M. Rawson,†,§ Blagoj S. Mitrevski,‡ and Philip J. Marriott‡ †
Defence Science and Technology Organisation, 506 Lorimer Street, Fishermans Bend, Victoria, Australia 3207 School of Chemistry, Monash University, Wellington Road, Clayton, Victoria, Australia 3800 § School of Aerospace, Mechanical and Manufacturing Engineering, RMIT University, 124a Latrobe Street, Melbourne, Victoria, Australia 3000 ‡
ABSTRACT: Thermal stressing experiments on a modified surrogate fuel and synthetic paraffinic kerosene (SPK) have been carried out under both static and dynamic conditions at 140 °C. In order to characterize the oxidation products, some key degradation compounds were monitored throughout the stressing experiment. Products resulting from ring closure reactions were also identified in the surrogate fuel and the SPK, with the identification of iso-benzofuranone and alkyldihydrofuranones. Furanones were quantified using gas chromatography−mass spectrometry (GC-MS) with high-performance liquid chromatography (HPLC) prefractionation. The formation of these furanones indicates that dynamic stressing promotes a reactivity that has only been reported at either higher temperatures or longer residence times.
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INTRODUCTION Modern middle distillates, including ultralow sulfur, severely hydroprocessed, synthetic, and bioderived fuels, are being subjected to increased demands, with respect to thermal stability. Thermal stability has long been an essential performance requirement for fuels and is now becoming increasingly important with modern engines inducing greater thermal stressing of fuels than ever before. Modern military aircraft require fuel to be used as a heat sink for avionics and lubricant cooling prior to being supplied to the engine for combustion. Diesel systems incorporating high-pressure common rail fuel manifolds have fuel supplied at high flow rates for hydraulic actuation of the injectors, with a large percentage being returned as unburnt fuel. In both scenarios, the fuel can be heated well past 100 °C1 and up to temperatures that have not been previously investigated in the literature, in terms of thermal stability.2 Previous work on thermal stability carried out by Corporan et al.3 focused on the 140+ °C temperature range with oxidation occurring over a 15-h period, and Grinstead and Zabarnick4 performed stressing at 180 °C for 5 h. Previous thermal oxidation work with ultralow sulfur diesel (ULSD) was carried out at 165−180 °C1,5 and is representative of temperatures experienced for return flow in high-pressure common rail applications. However, there is little work on the oxidation behavior of fuels at low temperatures with short (
