Physical and Chemical Analysis of Alcohol-to-Jet (ATJ) Fuel and Development of Surrogate Fuel Mixtures

Abstract

In this study, the chemical composition and physical properties of an alcohol-to-jet (ATJ) fuel were used to develop a surrogate mixture containing commercially available hydrocarbons. Analysis of the chemical composition of the ATJ showed a high quantity of two specific branched alkanes (2,2,4,4,6,8,8-heptamethylnonane and 2,2,4,6,6-pentamethylheptane) and a small quantity of other branched alkanes that are isomers of these two alkanes. Surrogate mixtures containing 2,2,4,4,6,8,8-heptamethylnonane and a mixture of isododecane isomers were prepared to determine what composition would match the density, viscosity, speed of sound, bulk modulus, surface tension, and flash point of ATJ. The optimal surrogate contained a 0.25 mass fraction of 2,2,4,4,6,8,8-heptamethylnonane in isododecane isomers. Combustion experiments were then conducted in a Yanmar diesel engine with fuel mixtures containing 70% (by volume) petroleum jet fuel with 30% ATJ, 2,2,4,4,6,8,8-heptamethylnonane, the optimal surrogate mixtures based on physical properties, or the isododecane isomers. The startup performances of the three 30% surrogate mixtures were very similar to that of the 70% JP-5 with 30% ATJ fuel. No significant differences were seen in the engine combustion characteristics of the three 70/30 surrogates, as compared to the base 70% JP-5/ 30% ATJ fuel mixture. These results show that a surrogate mixture has been successfully prepared that matches the physical and chemical properties and combustion behavior of an ATJ fuel.

Gas Fermentation—A Flexible Platform for Commercial Scale Production of Low-Carbon-Fuels and Chemicals from Waste and Renewable Feedstocks

“…There are currently multiple industrial ATJ projects for both ethanol and butanol conversions to jet fuel (Lane, 2015a ; LanzaTech, 2015 ). The ATJ fuels have undergone and continue to undergo rigorous testing to establish their use as drop-in fuels for commercial aircraft (Luning Prak et al, 2015 ). Successfully meeting these standards will expand the volume of fuels that may be sourced from renewable resources, such as biomass, and aid in keeping fossil fuels typically needed for aviation fuel in the ground.…”

Integration of computational modeling and experimental techniques to design fuel surrogates

“…Further, a combustion study was also carried out to investigate the engine performance with the surrogate fuel. While the experiment based method proposed by Luning Prak et al (2015) could lead to surrogate fuels with validated target properties, the model-based computer-aided method of Yunus et al (2014) is able to very quickly search over a wide range of solutions to identify a set of promising blends. Combining this approach with an experiment based approach, it is possible to quickly identify first, a small set of promising alternatives, then, through experiments to subsequently verify and fine-tune them to determine the optimal fuel-blend product.…”

Life cycle environmental analysis of ‘drop in’ alternative aviation fuels: a review

“…ATJ and its alternative term alcohol oligomerization is converted from a variety of different chemicals such as methanol, ethanol, butanol and a long chain of different fatty based alcohols. [112][113][114][115][116] According to Fig. 3, it has an FRL level of between 3 and 7 indicating signicant deviations in the type of feedstock used as well as the pathway conguration.…”