Experimental and modeling study of farnesane

Abstract

10Several alternative synthetic fuels are in discussion as a replacement for conventional fuels like Jet A-1 11 to cope with limited supplies of crude oil as well as their emissions connected with its use such as the 12 greenhouse gas CO 2 . One of the alternative fuels which have received high attention recently is far-13 nesane (2,6,10-trimethyldodecane), a biofuel produced from sugar using a biotechnological process. 14 In this paper, combustion characteristics of farnesane were investigated by measuring its ignition 15 delay time using a shock tube at elevated pressure (16 bar) and two different stoichiometries ( = 1.0 16 and = 2.0) and the laminar burning velocity at atmospheric and elevated pressures (1, 3, and 6 bar). 17These results were compared to a conventional Jet A-1 fuel showing that farnesane has a similar 18 combustion behavior. Furthermore, a reaction model was developed capable to predict the measured 19 combustion properties. The calculation of the ignition delay times yields excellent results when com-20 pared to the measurements; the computations of the laminar flame speeds are in good agreement 21 with the measurements. In addition, the reaction model was analyzed to get further insight into the 22 main reaction steps of farnesane oxidation. 23 24 eling 26 flight conditions, e.g. cold temperatures at high altitude. Moreover, this certification assures that the 40 new synthetic jet fuel is compatible with current engines and technology and that synthetic jet fuel 41 blends are interchangeable with conventional aviation fuels to prevent any logistics or storage prob-42 lems at airports that may arise due to the handling of different fuels. 43The use of coal or natural gas as feedstock for synthetic fuel production via the Fischer-Tropsch 44 process (CtL or GtL) led to the first approved alternative fuels for blending up to 50 %. Moreover a 45CtL production process exists which yields a fully synthetic jet fuel (FSJF), meaning that it can be used 46 as a replacement of crude oil based fuels without blending [2]. This is of course an alternative to the 47To benefit from biofuels -a sustainable replacement for crude oil based fuels, reduction of overall 52 emissions, including the greenhouse gas CO 2 [3, 9] -other fuels, processes and technologies were 53 developed. Approved in 2014 [10], a biofuel for aviation which can be used as a drop-in-fuel is far-54 nesane [8], a branched alkane with 15 carbon atoms as it is shown in Fig. 1. Its chemical name is 55 2,6,10-trimethyldodecane; for a better readability, only the name farnesane is used in this paper. The 56 production of farnesane has three major steps. At first, sugar is fermented by yeast to farnesene, a 57 molecule with four double bonds [11]. The second step is the hydrogenation from farnesene to far-58 nesane which in the last step is purified by distillation [8]. Whereas Jet A-1 is a multicomponent mix-59 ture [2] farnesane is a single component with a molecular size being in the upper range of the molec-60 ular size distribution typical...

Methods and tools for the characterisation of a generic jet fuel

“…Within a previous study, the uncertainties for the ignition delay times were derived from the assumption that the pressure has an uncertainty of ± 10 % due to post shock compression effects. This results in accuracies between ± 6 % and ± 15 % [11], which are similar for all measurements of the ignition delay time performed in this shock tube.…”

“…This method was exploited previously for the measurements of several alternative jet fuels, e.g. Coal-to-Liquid, Gas-to-Liquid, Alcohol-to-Jet, and Farnesane, and is described in more details, including the experimental set-up, in earlier publications [4][5][6][7][8][9][10][11]. The experiments were carried out at constant pressure (1 bar) and preheat temperature (473 K); the fuel/air equivalence (φ)-range was varied between 0.6 and 2.0 as shown in Figs.…”

“…The measurements of the ignition delay times are performed in a shock tube behind reflected shock waves as described earlier [7,8,10,11]. All ignition delay times given in the present work are derived as follows: The time difference between initiating the reactive system by the reflected shock wave and the peak of the excited CH*radical concentration measured at a wavelength λ = 431 nm are determined as a function of the temperature for a given mixture composition.…”

Combustion study of a surrogate jet fuel

“…Since the experimental approach has been already discussed in detail in previous studies (e.g. [2,41,42]) only a short description is given here.…”

Future Fuels—Analyses of the Future Prospects of Renewable Synthetic Fuels

“…In Figure 1, the extraction is located between the synthesis step and the product upgrading and refining step [27]. Based on this fuel, the combustion relevant parameters like ignition delay time and laminar flame speed were measured using shock tube experiments and a laminar conical burner experiment [28,29]. Emission behaviour was evaluated using a high-temperature flow reactor [30,31] in combination with mass spectrometry.…”