Commercial and military aviation is faced with challenges that include high fuel costs, undesirable emissions, and supply chain insecurity that result from the reliance on petroleum-based feedstocks. The development of alternative gas turbine fuels from renewable resources will likely be part of addressing these issues. The United States has established a target for one billion gallons of renewable fuels to enter the supply chain by 2018. These alternative fuels will have to be very similar in properties, chemistry, and composition to existing fuels. To further this goal, the National Jet Fuel Combustion Program (a collaboration of multiple U.S. agencies under the auspices of the Federal Aviation Administration, FAA) is coordinating measurements on three reference gas turbine fuels to be used as a basis of comparison. These fuels are reference fuels with certain properties that are at the limits of experience. These fuels include a low viscosity, low flash point, high hydrogen content “best case” JP-8 (POSF 10264) fuel, a relatively high viscosity, high flash point, low hydrogen content “worst case” JP-5 (POSF 10259) fuel, and a Jet-A (POSF 10325) fuel with relatively average properties. A comprehensive speciation of these fuels is provided in this paper by use of high resolution gas chromatography/quadrupole time-of-flight – mass spectrometry (GC/QToF-MS), which affords unprecedented resolution and exact molecular formula capabilities. The volatility information as derived from the measurement of the advanced distillation curve temperatures, Tk and Th, provides an approximation of the vapor liquid equilibrium and examination of the composition channels provides detailed insight into thermochemical data. A comprehensive understanding of the compositional and thermophysical data of gas turbine fuels is required not only for comparison but also for modeling of such complex mixtures, which will, in turn, aid in the development of new fuels with the goals of diversified feedstocks, decreased pollution, and increased efficiency.

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Incremental but fundamental changes are currently being made to fuel composition and combustion strategies to diversify energy feedstocks, decrease pollution, and increase engine efficiency. The increase in parameter space (by having many variables in play simultaneously) makes it difficult at best to propose strategic changes to engine and fuel design by use of conventional build-and-test methodology. To make changes in the most time-and cost-effective manner, it is imperative that new computational tools and surrogate fuels are developed. Currently, sets of fuels are being characterized by industry groups, such as the Coordinating Research Council (CRC) and other entities, so that researchers in different laboratories have access to fuels with consistent properties. In this work, six gasolines (FACE A, C, F, G, I, and J) are characterized by the advanced distillation curve (ADC) method to determine the composition and enthalpy of combustion in various distillate volume fractions. Tracking the composition and enthalpy of distillate fractions provides valuable information for determining structure property relationships, and moreover, it provides the basis for the development of equations of state that can describe the thermodynamic properties of these complex mixtures and lead to development of surrogate fuels composed of major hydrocarbon classes found in target fuels. ■ INTRODUCTIONIncremental but fundamental changes are currently being made to fuel composition and combustion strategies, enabling engines to accept diversified energy feedstocks, decrease pollution, and increase efficiency. To make changes in the most time-and cost-effective manner, the design and development of surrogate fuels is of utmost importance to computational studies, experimental design, and thermophysical property modeling. 1−3 Surrogate blends with a limited number of components can more readily provide insight into property effects on mixing, vaporization, and combustion, which lead to improvements in engine efficiency, decreased emissions, and enhanced performance. 4−9 Indeed, both theoretical and experimental studies of surrogates (frequently blends of components, such as n-heptane and isooctane) have been conducted comparing the properties of proposed surrogates to those of gasoline. 10−18 In addition, surrogate fuels have value as time invariant references, by allowing for direct comparisons of results from different laboratories using the same surrogate fuel. This approach avoids the temporal differences in the composition of individual refinery streams, which are blended together to make finished fuels, because commercial fuels and even reference fuels tend to vary over time. 3 Despite this variability, one of the best options for researchers looking for fuel consistency is the use of reference fuel sets characterized by industry groups, such as the Coordinating Research Council (CRC) Fuels for Advanced Combustion Engines (FACE) group. 19 The FACE group is composed of volunteers from industry, government, and academia, who wo...