The oxidation of syngas mixtures was investigated experimentally and simulated with an updated chemical kinetic model. Ignition delay times for H 2 /CO/O 2 /N 2 /Ar mixtures have been measured using two rapid compression machines (RCM) and shock tubes at pressures from 1 to 70 bar, over a temperature range of 914-2220 K and at equivalence ratios from 0.1 to 4.0. Results show a strong dependence of ignition times on temperature and

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The ignition delay times of diluted hydrogen / reference gas (92% methane, 8% ethane) / O 2 / Ar mixtures with hydrogen contents of 0, 40, 80 and 100% were determined in a highpressure shock tube at equivalence ratios  = 0.5 and 1.0 (dilution 1:5). The temperature range was 900 K  T  1800 K at pressures of about 1, 4 and 16 bar.The reference gas and the 40% hydrogen / 60% reference gas data showed typical characteristics of hydrocarbon systems and can be represented by:(reference gas) andThe pure hydrogen data exhibit a more complex pressure dependence with the 16 bar values having the slowest ignition delay times at lower temperatures and the fastest ignition delay times at higher temperatures. No dependence on the equivalence ratio was observed.The 80% hydrogen / 20% reference gas data display characteristics of hydrocarbon and hydrogen systems.The comparison of the measurements to MPFR-CHEMKIN II simulations with different mechanisms shows that the predictions of all tested mechanisms with the exception of the GRI3.0 agree well with the experimental values for reference gas, 40% hydrogen / 60% reference gas and partly for 80% hydrogen / 20% reference gas and 100% hydrogen. None of the mechanisms can represent the observed reduction of the activation energy at low 3 temperatures of pure hydrogen and of 80% hydrogen / 20% reference gas at p  4 bar.Literature mechanisms which were developed for H 2 or for mixtures with a dominating H 2 subsystem cannot predict the observed reduction of the activation energies, either.

The kinetics of oxidation of a Coal-to-Liquid (CtL) Fully Synthetic Jet Fuel (FSJF) was studied using three complementary experiments operating over a wide range of conditions: a jet-stirred reactor (p = 10 bar), constant mean residence time of 1 s, over the temperature range 770-1070 K, and for equivalence ratios ϕ = 0.5, 1.0, and 2.0; a shock-tube (p ~ 16 bar, temperature range between 900 and 1400 K, ϕ = 0.5 and ϕ = 1), and a conical flame burner (preheat temperature T 0 = 473 K, and for two pressure regimes: p = 1 bar for equivalence ratios ranging from 0.95 to 1.4, and p = 3 bar for equivalence ratios ranging from 0.95 to 1.3). Concentration profiles of reactants, stable intermediates, and final products in the jet-stirred reactor were obtained by probe sampling followed by on-line and off-line gas chromatography analyses and on-line Fourier Transformed Infra-Red spectrometry. Ignition delay times were determined behind reflected shock waves by measuring time-dependent CH* emission at 431 nm. Flame speeds were determined by applying the cone angle method. Comparison with corresponding results for Jet A-1 was performed showing similar combustion properties. The oxidation of the CtL-fuel under these conditions was modeled using a detailed kinetic reaction mechanism consisting of 8217 reactions and 2185 species and a 4-component surrogate fuel mixture (n-decane, iso-octane, n-propylcyclohexane, and npropylbenzene). A reasonable representation of the kinetics of oxidation of this FSJF was obtained. The model showed good agreement with concentration profiles measured in a jetstirred reactor at 10 bar over a range of temperatures (550-1150 K) and equivalence ratios (0.5-2). Good agreement between measured and predicted ignition delay times was found for the investigated fuel air mixtures, with significantly longer ignition delay times predicted. Also, the ignition behavior of the surrogate is mainly influenced by the n-alkane and not by the addition of iso-alkanes, naphthenes, and aromatics. In general, a reasonable agreement between predicted and measured burning velocity data exists, with larger deviations at higher pressure. No deviation is to be seen between burning velocity data for Jet A-1 and CtL, within the uncertainty range. Within the parameter range studied, the measured data of burning 4 velocity and ignition delay time agree with data obtained earlier for petrol-derived kerosene. Our findings support the potential of the CtL/air mixture investigated to serve as an alternative aviation fuel.

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The reaction kinetics of Ethylene Glycol (EG) is studied, due to its similarity in chemical composition and physical properties, as a model fuel for pyrolysis oil. Recently, the combination of fast pyrolysis of residual biomass and subsequent gasification of the pyrolysis oil has gained high interest. In the gasification process, oxygen is often used as a gasifying agent (e.g. autothermal gasification) which led us to study EG under oxidation condition. This study has experimental and modeling objectives: We obtain novel experimental data that we use for validation of our EG oxidation model that enable predictive modeling and optimization of gasifiers through multi-dimensional CFD simulations. Both, detailed and reduced skeletal models are obtained. The validation data needed for the model is studied in two different types of experiments namely, (1) ignition delay times obtained behind reflected shock waves in the temperature range of 800-1500 K at 16 bar and, (2) quantitative species profiles measured in a high temperature flow reactor setup for fuel equivalence ratios  = 1.0 and 2.0 in the temperature range of 700-1200 K. Both experiments are performed in the EG-system for the first time providing the relevant basis for the understanding on how EG decomposes and for the optimization of the reaction mechanism. The influence of different product channels on the reactivity of the EG system is investigated and leads us to pose the question, if enol can be formed in this combustion (oxidative) environment.

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Recently, the development of viable alternative aviation fuels has attracted much interest, for several reasons, with reduction of greenhouse gas (GHG) emissions and ensuring security of supply at affordable prices among them. In the present work, several alternative aviation fuelsexisting and potential-are investigated by focusing on their heat release: Gas-to-Liquid (GtL: representing a Fischer-Tropsch Synthetic Paraffinic Kerosene (FT-SPK)), a fully synthetic jet fuel (FSJF: Coal-to-Liquid (CtL)), and blends of GtL with 20% 1-hexanol or 50% naphthenic cut, respectively. Burning velocities are measured at ambient pressures and at elevated preheat temperatures exploiting the cone angle method; equivalence ratios are between about ϕ = 1.0 and ϕ = 1.4. The measured data are used for the validation of a detailed chemical reaction model consisting of 4642 reactions involving 1075 species developed by Dagaut et al. [22-23] following the concept of a surrogate. The comparison between measured burning velocities and predicted laminar flame speeds shows reasonably good agreement with the model for the range of conditions considered in this study. The main features of the reaction model are also discussed, using sensitivity and rate of production analysis. Finally, the experimental data are compared with results obtained earlier for crude-oil kerosene. The findings support the potential of the investigated fuel mixtures to serve as alternative aviation fuels.