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Philippe Dagaut - One of the best experts on this subject based on the ideXlab platform.
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kinetics of propyl acetate oxidation experiments in a jet Stirred Reactor ab initio calculations and rate constant determination
37th International Symposium on Combustion, 2019Co-Authors: Philippe Dagaut, Guillaume Dayma, Sebastien Thion, Zeynep Serinyel, Maxence Lailliau, Baptiste SirjeanAbstract:Abstract In this study, the oxidation of propyl acetate (PA) was investigated experimentally in a jet-Stirred Reactor and theoretically by electronic structure calculations. Experiments were performed at 1 and 10 atm for three different equivalence ratios ( φ = 0.5, 1, and 2) at each pressure. These experimental results show the strong influence of the molecular reaction yielding propene and acetic acid throughout the investigated temperature range (700–1250 K). In order to better understand the oxidation process of propyl acetate, a detailed kinetic mechanism consisting of 628 species involved in 3927 reversible reactions has been developed laying on previous works on esters oxidation and theoretical calculations performed in this study. These calculations compare well with the rate constant experimentally determined in our jet-Stirred Reactor for the molecular reaction: k = 1.292 × 10 13 exp ( − 25167 T ) ( s − 1 ) (700–1010 K).
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an experimental chemical kinetic study of the oxidation of diethyl ether in a jet Stirred Reactor and comprehensive modeling
Combustion and Flame, 2018Co-Authors: Sebastien Thion, Guillaume Dayma, Zeynep Serinyel, Maxence Lailliau, Philippe DagautAbstract:Abstract The oxidation of diethyl ether was studied experimentally in a jet-Stirred Reactor. Fuel-lean, stoichiometric and fuel-rich mixtures were oxidized at a constant fuel mole fraction (1000 ppm), at temperatures ranging from 450 to 1250 K, pressures of 1 and 10 atm, and constant residence time (70 and 700 ms, respectively). In total, six mixtures were tested at both pressures. Mole fraction profiles were obtained using gas chromatography and Fourier transform infrared spectrometry. The fuel mole fraction profiles, as well as some reaction intermediate and product profiles indicated strong low-temperature chemistry at high pressure. On the other hand, at atmospheric pressure this behavior was observed to a very small extent and only with the lean and stoichiometric mixtures. These data were compared to modeling results using literature mechanisms for diethyl ether oxidation. None of these predicted low-temperature reactivity under present conditions. Therefore, a kinetic mechanism is proposed in this study, based on recently computed kinetic parameters from literature. It shows good performances for representing the present experimental data as well as experimental data found in literature consisting of ignition delay times, laminar flame speeds and flame structure.
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exploration of the oxidation chemistry of dimethoxymethane jet Stirred Reactor experiments and kinetic modeling
Combustion and Flame, 2018Co-Authors: Wenyu Sun, Nils Hansen, Tao Tao, Bin Yang, Maxence Lailliau, Philippe DagautAbstract:Abstract Dimethoxymethane (DMM, CH3OCH2OCH3) is a practical diesel additive, as well as a simple homologue in the class of polyoxymethylene dimethyl ethers (POMDMEs) which are considered as promising alternative fuels. To acquire an in-depth knowledge of DMM oxidation kinetics, the chemistry of an externally heated fuel-lean (ϕ = 0.5) DMM/O2/Ar mixture was investigated in a jet-Stirred Reactor (JSR) operated at near-atmospheric pressure (750 Torr). A molecular-beam mass spectrometer (MBMS) employing synchrotron photoionization was used to probe reactive intermediates. High-pressure (10 atm) oxidation experiments covering different equivalence ratios (0.2, 0.5 and 1.5) were carried out using another JSR facility equipped with gas chromatography (GC) and Fourier transform infrared spectrometry (FTIR) for speciation measurements. A new kinetic model was constructed and validated against the current measurements as well as those reported in literature. No obvious low-temperature reactivity was observed for DMM under the investigated conditions, though DMM has a long enough chain to allow internal hydrogen transfers leading to chain-branching. The kinetic modeling showed that hydrogen abstractions from the central ( OCH2O ) moiety are favored, producing dominantly the CH3OĊHOCH3 fuel radical, which then rapidly decomposes instead of leading to chain-branching via O2 addition. In contrast, the minor fuel radical CH3OCH2OĊH2 can go through the O2 addition and the subsequent isomerization steps, as confirmed by the detection of cyclic ether species. Another impact of the fast CH3 production from CH3OĊHOCH3 β-scission is that CH3O2H serves as an important OH provider, facilitating the fuel consumption at medium temperatures. Major fuel destruction patterns could also apply to larger POMDME compounds.
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exploring the negative temperature coefficient behavior of acetaldehyde based on detailed intermediate measurements in a jet Stirred Reactor
Combustion and Flame, 2018Co-Authors: Nils Hansen, Philippe Dagaut, Bingjie Chen, Zhandong Wang, Ahren W. Jasper, Kai Moshammer, Can Huang, Bin YangAbstract:Abstract Acetaldehyde is an observed emission species and a key intermediate produced during the combustion and low-temperature oxidation of fossil and bio-derived fuels. Investigations into the low-temperature oxidation chemistry of acetaldehyde are essential to develop a better core mechanism and to better understand auto-ignition and cool flame phenomena. Here, the oxidation of acetaldehyde was studied at low-temperatures (528–946 K) in a jet-Stirred Reactor (JSR) with the corrected residence time of 2.7 s at 700 Torr. This work describes a detailed set of experimental results that capture the negative temperature coefficient (NTC) behavior in the low-temperature oxidation of acetaldehyde. The mole fractions of 28 species were measured as functions of the temperature by employing a vacuum ultra-violet photoionization molecular-beam mass spectrometer. To explain the observed NTC behavior, an updated mechanism was proposed, which well reproduces the concentration profiles of many observed peroxide intermediates. The kinetic analysis based on the updated mechanism reveals that the NTC behavior of acetaldehyde oxidation is caused by the competition between the O2-addition to and the decomposition of the CH3CO radical.
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an experimental study in a jet Stirred Reactor and a comprehensive kinetic mechanism for the oxidation of methyl ethyl ketone
Proceedings of the Combustion Institute, 2017Co-Authors: Guillaume Dayma, Sebastien Thion, Zeynep Serinyel, Pascal Dievart, Pierre Van Cauwenberghe, Philippe DagautAbstract:The first speciation data regarding the oxidation of methyl ethyl ketone (MEK) are presented. Fuel-lean, stoichiometric and fuel-rich mixtures were studied at constant fuel concentration (1000 ppm) in a jet Stirred Reactor at atmospheric and high pressure (10 atm). A detailed kinetic mechanism is proposed based on theoretical calculations at the G3//MP2/aug-cc-pVDZ level of theory. The new rate constants differ substantially from the estimations employed in the previous MEK submechanism available in the literature, and impact MEK oxidation pathways. The model was tested successfully against these new speciation data and other available data (ignition delay times, flame speeds, pyrolysis species profile). However, some deficiencies in the model were identified concerning methyl ketene and methyl vinyl ketone. Reaction path analyses are used to interpret the results.
Guillaume Dayma - One of the best experts on this subject based on the ideXlab platform.
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kinetics of propyl acetate oxidation experiments in a jet Stirred Reactor ab initio calculations and rate constant determination
37th International Symposium on Combustion, 2019Co-Authors: Philippe Dagaut, Guillaume Dayma, Sebastien Thion, Zeynep Serinyel, Maxence Lailliau, Baptiste SirjeanAbstract:Abstract In this study, the oxidation of propyl acetate (PA) was investigated experimentally in a jet-Stirred Reactor and theoretically by electronic structure calculations. Experiments were performed at 1 and 10 atm for three different equivalence ratios ( φ = 0.5, 1, and 2) at each pressure. These experimental results show the strong influence of the molecular reaction yielding propene and acetic acid throughout the investigated temperature range (700–1250 K). In order to better understand the oxidation process of propyl acetate, a detailed kinetic mechanism consisting of 628 species involved in 3927 reversible reactions has been developed laying on previous works on esters oxidation and theoretical calculations performed in this study. These calculations compare well with the rate constant experimentally determined in our jet-Stirred Reactor for the molecular reaction: k = 1.292 × 10 13 exp ( − 25167 T ) ( s − 1 ) (700–1010 K).
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an experimental chemical kinetic study of the oxidation of diethyl ether in a jet Stirred Reactor and comprehensive modeling
Combustion and Flame, 2018Co-Authors: Sebastien Thion, Guillaume Dayma, Zeynep Serinyel, Maxence Lailliau, Philippe DagautAbstract:Abstract The oxidation of diethyl ether was studied experimentally in a jet-Stirred Reactor. Fuel-lean, stoichiometric and fuel-rich mixtures were oxidized at a constant fuel mole fraction (1000 ppm), at temperatures ranging from 450 to 1250 K, pressures of 1 and 10 atm, and constant residence time (70 and 700 ms, respectively). In total, six mixtures were tested at both pressures. Mole fraction profiles were obtained using gas chromatography and Fourier transform infrared spectrometry. The fuel mole fraction profiles, as well as some reaction intermediate and product profiles indicated strong low-temperature chemistry at high pressure. On the other hand, at atmospheric pressure this behavior was observed to a very small extent and only with the lean and stoichiometric mixtures. These data were compared to modeling results using literature mechanisms for diethyl ether oxidation. None of these predicted low-temperature reactivity under present conditions. Therefore, a kinetic mechanism is proposed in this study, based on recently computed kinetic parameters from literature. It shows good performances for representing the present experimental data as well as experimental data found in literature consisting of ignition delay times, laminar flame speeds and flame structure.
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an experimental study in a jet Stirred Reactor and a comprehensive kinetic mechanism for the oxidation of methyl ethyl ketone
Proceedings of the Combustion Institute, 2017Co-Authors: Guillaume Dayma, Sebastien Thion, Zeynep Serinyel, Pascal Dievart, Pierre Van Cauwenberghe, Philippe DagautAbstract:The first speciation data regarding the oxidation of methyl ethyl ketone (MEK) are presented. Fuel-lean, stoichiometric and fuel-rich mixtures were studied at constant fuel concentration (1000 ppm) in a jet Stirred Reactor at atmospheric and high pressure (10 atm). A detailed kinetic mechanism is proposed based on theoretical calculations at the G3//MP2/aug-cc-pVDZ level of theory. The new rate constants differ substantially from the estimations employed in the previous MEK submechanism available in the literature, and impact MEK oxidation pathways. The model was tested successfully against these new speciation data and other available data (ignition delay times, flame speeds, pyrolysis species profile). However, some deficiencies in the model were identified concerning methyl ketene and methyl vinyl ketone. Reaction path analyses are used to interpret the results.
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a chemical kinetic study of the oxidation of dibutyl ether in a jet Stirred Reactor
Combustion and Flame, 2017Co-Authors: Guillaume Dayma, Casimir Togbé, Sebastien Thion, Zeynep Serinyel, Philippe DagautAbstract:Abstract The oxidation of dibutyl-ether, a potential lignocellulosic biofuel was studied in a jet-Stirred Reactor. Fuel-lean, stoichiometric and fuel-rich mixtures were oxidized at a constant fuel mole fraction (1000 ppm), at temperatures ranging from 470 to 1250 K, pressures of 1 and 10 atm, and constant residence time (70 and 700 ms, respectively). The mole fraction profiles obtained through sonic probe sampling, gas chromatography and Fourier transform infrared spectrometry were used to develop a detailed kinetic mechanism for the oxidation of DBE. The carbon neighboring the ether group was found to be the most favorable site for H-abstraction reactions and the chemistry of the corresponding fuel radical drives the overall reactivity. The fuel concentration profiles indicated strong low-temperature chemistry at both pressures: two negative temperature coefficient regions were observed, notably on the 10 atm experiments. This unusual behavior was investigated by means of a rate of production analysis using the mechanism developed in this work. This analysis showed that the low-temperature reactivity stems from the low-temperature chemistry of the fuel and of smaller species such as C4H9 which are triggered at different threshold temperatures. The proposed mechanism shows good performances for representing the present experimental data, as well as ignition delay time and flame speed data available from the literature.
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experimental and detailed kinetic modeling study of cyclopentanone oxidation in a jet Stirred Reactor at 1 and 10 atm
Energy & Fuels, 2017Co-Authors: Sebastien Thion, Guillaume Dayma, Casimir Togbé, Zeynep Serinyel, Philippe DagautAbstract:Cyclopentanone oxidation was studied in a jet-Stirred Reactor at 1 and 10 atm and over the temperature range of 730–1280 K for fuel-lean (φ = 0.5), stoichiometric, and fuel-rich (φ = 2) mixtures. A total of 16 reaction intermediates and products were identified and quantified using online Fourier transform infrared spectrometry and offline gas chromatography. A kinetic submodel was developed, supported by theoretical calculations for the rate constants of hydrogen abstraction reactions by H atoms and OH and CH3 radicals at the MP2/aug-cc-pVDZ level of theory. The resulting model consisting of 343 species involved in 2065 reactions was used to simulate the present experiments and showed good agreement with the data. The main oxygenated intermediates are aldehydes, and cyclopentenone was also found to be an important species for cyclopentanone oxidation. The rate of production analyses showed that cyclopentanone is mainly consumed by a sequence of reactions producing CO and the but-1-en-4-yl radical. Unimol...
Casimir Togbé - One of the best experts on this subject based on the ideXlab platform.
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a chemical kinetic study of the oxidation of dibutyl ether in a jet Stirred Reactor
Combustion and Flame, 2017Co-Authors: Guillaume Dayma, Casimir Togbé, Sebastien Thion, Zeynep Serinyel, Philippe DagautAbstract:Abstract The oxidation of dibutyl-ether, a potential lignocellulosic biofuel was studied in a jet-Stirred Reactor. Fuel-lean, stoichiometric and fuel-rich mixtures were oxidized at a constant fuel mole fraction (1000 ppm), at temperatures ranging from 470 to 1250 K, pressures of 1 and 10 atm, and constant residence time (70 and 700 ms, respectively). The mole fraction profiles obtained through sonic probe sampling, gas chromatography and Fourier transform infrared spectrometry were used to develop a detailed kinetic mechanism for the oxidation of DBE. The carbon neighboring the ether group was found to be the most favorable site for H-abstraction reactions and the chemistry of the corresponding fuel radical drives the overall reactivity. The fuel concentration profiles indicated strong low-temperature chemistry at both pressures: two negative temperature coefficient regions were observed, notably on the 10 atm experiments. This unusual behavior was investigated by means of a rate of production analysis using the mechanism developed in this work. This analysis showed that the low-temperature reactivity stems from the low-temperature chemistry of the fuel and of smaller species such as C4H9 which are triggered at different threshold temperatures. The proposed mechanism shows good performances for representing the present experimental data, as well as ignition delay time and flame speed data available from the literature.
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experimental and detailed kinetic modeling study of cyclopentanone oxidation in a jet Stirred Reactor at 1 and 10 atm
Energy & Fuels, 2017Co-Authors: Sebastien Thion, Guillaume Dayma, Casimir Togbé, Zeynep Serinyel, Philippe DagautAbstract:Cyclopentanone oxidation was studied in a jet-Stirred Reactor at 1 and 10 atm and over the temperature range of 730–1280 K for fuel-lean (φ = 0.5), stoichiometric, and fuel-rich (φ = 2) mixtures. A total of 16 reaction intermediates and products were identified and quantified using online Fourier transform infrared spectrometry and offline gas chromatography. A kinetic submodel was developed, supported by theoretical calculations for the rate constants of hydrogen abstraction reactions by H atoms and OH and CH3 radicals at the MP2/aug-cc-pVDZ level of theory. The resulting model consisting of 343 species involved in 2065 reactions was used to simulate the present experiments and showed good agreement with the data. The main oxygenated intermediates are aldehydes, and cyclopentenone was also found to be an important species for cyclopentanone oxidation. The rate of production analyses showed that cyclopentanone is mainly consumed by a sequence of reactions producing CO and the but-1-en-4-yl radical. Unimol...
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jet Stirred Reactor oxidation of alkane rich face gasoline fuels
Proceedings of the Combustion Institute, 2017Co-Authors: Bingjie Chen, Philippe Dagaut, Casimir Togbé, Zhandong Wang, Mani S SarathyAbstract:Abstract Understanding species evolution upon gasoline fuel oxidation can aid in mitigating harmful emissions and improving combustion efficiency. Experimentally measured speciation profiles are also important targets for surrogate fuel kinetic models. This work presents the low- and high-temperature oxidation of two alkane-rich FACE gasolines (A and C, Fuels for Advanced Combustion Engines) in a jet-Stirred Reactor at 10 bar and equivalence ratios from 0.5 to 2 by probe sampling combined with gas chromatography and Fourier Transformed Infrared Spectrometry analysis. Detailed speciation profiles as a function of temperature are presented and compared to understand the combustion chemistry of these two real fuels. Simulations were conducted using three surrogates (i.e., FGA2, FGC2, and FRF 84), which have similar physical and chemical properties as the two gasolines. The experimental results reveal that the reactivity and major product distributions of these two alkane-rich FACE fuels are very similar, indicating that they have similar global reactivity despite their different compositions. The simulation results using all the surrogates capture the two-stage oxidation behavior of the two FACE gasolines, but the extent of low temperature reactivity is over-predicted. The simulations were analyzed, with a focus on the n-heptane and n-butane sub-mechanisms, to help direct the future model development and surrogate fuel formulation strategies.
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kinetics of oxidation of cyclohexanone in a jet Stirred Reactor experimental and modeling
Proceedings of the Combustion Institute, 2015Co-Authors: Guillaume Dayma, Casimir Togbé, Zeynep Serinyel, Aristotelis M Zaras, Philippe DagautAbstract:Abstract The kinetics of oxidation of cyclohexanone (CAS 108-94-1) was studied experimentally in a fused silica jet Stirred Reactor (JSR) for the first time. The experiments were performed in the temperature range 530–1220 K, at an operating pressure of 10 atm, for equivalence ratios ranging from 0.5 to 4, and with an initial fuel concentration of 1000 ppm ( φ = 0.5, 1.0 and 2.0) and 1500 ppm ( φ = 4.0). Concentration profiles of reactants, stable intermediates and products were measured at fixed residence time and variable temperature by gas chromatography (GC) and Fourier transform infrared spectroscopy (FTIR) after sonic probe sampling. Cyclic intermediates experimentally observed include, 2-cyclohexen-1-one, cyclopentene, cyclopentadiene and aromatics such as benzene and toluene, the latter in trace amounts only for rich mixtures. The experimental data were used to validate a detailed kinetic reaction mechanism. A reasonable agreement between the present experimental results and the computations was observed. Kinetic analyses (sensitivity and reaction paths) were used to interpret the results.
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experimental and modeling study of the oxidation of n and iso butanal
Combustion and Flame, 2013Co-Authors: Peter S Veloo, Philippe Dagaut, Casimir Togbé, Charles K. Westbrook, Guillaume Dayma, Mani S Sarathy, Fokion N EgolfopoulosAbstract:Understanding the kinetics of large molecular weight aldehydes is essential in the context of both conventional and alternative fuels. For example, they are key intermediates formed during the low-temperature oxidation of hydrocarbons as well as during the high-temperature oxidation of oxygenated fuels such as alcohols. In this study, an experimental and kinetic modeling investigation of n-butanal (n-butyraldehyde) and iso-butanal (iso-butyraldehyde or 2-methylpropanal) oxidation kinetics was performed. Experiments were performed in a jet Stirred Reactor and in counterflow flames over a wide range of equivalence ratios, temperatures, and pressures. The jet Stirred Reactor was utilized to observe the evolution of stable intermediates and products for the oxidation of n- and iso-butanal at elevated pressures and low to intermediate temperatures. The counterflow configuration was utilized for the determination of laminar flame speeds. A detailed chemical kinetic interpretative model was developed and validated consisting of 244 species and 1198 reactions derived from a previous study of the oxidation of propanal (propionaldehyde). Extensive reaction pathway and sensitivity analysis was performed to provide detailed insight into the mechanisms governing low-, intermediate-, and high-temperature reactivity. The simulation results using the present model are in good agreement with the experimental laminar flame speeds and well within a factor of two of the speciation data obtained in the jet Stirred Reactor.
Zeynep Serinyel - One of the best experts on this subject based on the ideXlab platform.
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kinetics of propyl acetate oxidation experiments in a jet Stirred Reactor ab initio calculations and rate constant determination
37th International Symposium on Combustion, 2019Co-Authors: Philippe Dagaut, Guillaume Dayma, Sebastien Thion, Zeynep Serinyel, Maxence Lailliau, Baptiste SirjeanAbstract:Abstract In this study, the oxidation of propyl acetate (PA) was investigated experimentally in a jet-Stirred Reactor and theoretically by electronic structure calculations. Experiments were performed at 1 and 10 atm for three different equivalence ratios ( φ = 0.5, 1, and 2) at each pressure. These experimental results show the strong influence of the molecular reaction yielding propene and acetic acid throughout the investigated temperature range (700–1250 K). In order to better understand the oxidation process of propyl acetate, a detailed kinetic mechanism consisting of 628 species involved in 3927 reversible reactions has been developed laying on previous works on esters oxidation and theoretical calculations performed in this study. These calculations compare well with the rate constant experimentally determined in our jet-Stirred Reactor for the molecular reaction: k = 1.292 × 10 13 exp ( − 25167 T ) ( s − 1 ) (700–1010 K).
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an experimental chemical kinetic study of the oxidation of diethyl ether in a jet Stirred Reactor and comprehensive modeling
Combustion and Flame, 2018Co-Authors: Sebastien Thion, Guillaume Dayma, Zeynep Serinyel, Maxence Lailliau, Philippe DagautAbstract:Abstract The oxidation of diethyl ether was studied experimentally in a jet-Stirred Reactor. Fuel-lean, stoichiometric and fuel-rich mixtures were oxidized at a constant fuel mole fraction (1000 ppm), at temperatures ranging from 450 to 1250 K, pressures of 1 and 10 atm, and constant residence time (70 and 700 ms, respectively). In total, six mixtures were tested at both pressures. Mole fraction profiles were obtained using gas chromatography and Fourier transform infrared spectrometry. The fuel mole fraction profiles, as well as some reaction intermediate and product profiles indicated strong low-temperature chemistry at high pressure. On the other hand, at atmospheric pressure this behavior was observed to a very small extent and only with the lean and stoichiometric mixtures. These data were compared to modeling results using literature mechanisms for diethyl ether oxidation. None of these predicted low-temperature reactivity under present conditions. Therefore, a kinetic mechanism is proposed in this study, based on recently computed kinetic parameters from literature. It shows good performances for representing the present experimental data as well as experimental data found in literature consisting of ignition delay times, laminar flame speeds and flame structure.
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an experimental study in a jet Stirred Reactor and a comprehensive kinetic mechanism for the oxidation of methyl ethyl ketone
Proceedings of the Combustion Institute, 2017Co-Authors: Guillaume Dayma, Sebastien Thion, Zeynep Serinyel, Pascal Dievart, Pierre Van Cauwenberghe, Philippe DagautAbstract:The first speciation data regarding the oxidation of methyl ethyl ketone (MEK) are presented. Fuel-lean, stoichiometric and fuel-rich mixtures were studied at constant fuel concentration (1000 ppm) in a jet Stirred Reactor at atmospheric and high pressure (10 atm). A detailed kinetic mechanism is proposed based on theoretical calculations at the G3//MP2/aug-cc-pVDZ level of theory. The new rate constants differ substantially from the estimations employed in the previous MEK submechanism available in the literature, and impact MEK oxidation pathways. The model was tested successfully against these new speciation data and other available data (ignition delay times, flame speeds, pyrolysis species profile). However, some deficiencies in the model were identified concerning methyl ketene and methyl vinyl ketone. Reaction path analyses are used to interpret the results.
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a chemical kinetic study of the oxidation of dibutyl ether in a jet Stirred Reactor
Combustion and Flame, 2017Co-Authors: Guillaume Dayma, Casimir Togbé, Sebastien Thion, Zeynep Serinyel, Philippe DagautAbstract:Abstract The oxidation of dibutyl-ether, a potential lignocellulosic biofuel was studied in a jet-Stirred Reactor. Fuel-lean, stoichiometric and fuel-rich mixtures were oxidized at a constant fuel mole fraction (1000 ppm), at temperatures ranging from 470 to 1250 K, pressures of 1 and 10 atm, and constant residence time (70 and 700 ms, respectively). The mole fraction profiles obtained through sonic probe sampling, gas chromatography and Fourier transform infrared spectrometry were used to develop a detailed kinetic mechanism for the oxidation of DBE. The carbon neighboring the ether group was found to be the most favorable site for H-abstraction reactions and the chemistry of the corresponding fuel radical drives the overall reactivity. The fuel concentration profiles indicated strong low-temperature chemistry at both pressures: two negative temperature coefficient regions were observed, notably on the 10 atm experiments. This unusual behavior was investigated by means of a rate of production analysis using the mechanism developed in this work. This analysis showed that the low-temperature reactivity stems from the low-temperature chemistry of the fuel and of smaller species such as C4H9 which are triggered at different threshold temperatures. The proposed mechanism shows good performances for representing the present experimental data, as well as ignition delay time and flame speed data available from the literature.
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experimental and detailed kinetic modeling study of cyclopentanone oxidation in a jet Stirred Reactor at 1 and 10 atm
Energy & Fuels, 2017Co-Authors: Sebastien Thion, Guillaume Dayma, Casimir Togbé, Zeynep Serinyel, Philippe DagautAbstract:Cyclopentanone oxidation was studied in a jet-Stirred Reactor at 1 and 10 atm and over the temperature range of 730–1280 K for fuel-lean (φ = 0.5), stoichiometric, and fuel-rich (φ = 2) mixtures. A total of 16 reaction intermediates and products were identified and quantified using online Fourier transform infrared spectrometry and offline gas chromatography. A kinetic submodel was developed, supported by theoretical calculations for the rate constants of hydrogen abstraction reactions by H atoms and OH and CH3 radicals at the MP2/aug-cc-pVDZ level of theory. The resulting model consisting of 343 species involved in 2065 reactions was used to simulate the present experiments and showed good agreement with the data. The main oxygenated intermediates are aldehydes, and cyclopentenone was also found to be an important species for cyclopentanone oxidation. The rate of production analyses showed that cyclopentanone is mainly consumed by a sequence of reactions producing CO and the but-1-en-4-yl radical. Unimol...
Sebastien Thion - One of the best experts on this subject based on the ideXlab platform.
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kinetics of propyl acetate oxidation experiments in a jet Stirred Reactor ab initio calculations and rate constant determination
37th International Symposium on Combustion, 2019Co-Authors: Philippe Dagaut, Guillaume Dayma, Sebastien Thion, Zeynep Serinyel, Maxence Lailliau, Baptiste SirjeanAbstract:Abstract In this study, the oxidation of propyl acetate (PA) was investigated experimentally in a jet-Stirred Reactor and theoretically by electronic structure calculations. Experiments were performed at 1 and 10 atm for three different equivalence ratios ( φ = 0.5, 1, and 2) at each pressure. These experimental results show the strong influence of the molecular reaction yielding propene and acetic acid throughout the investigated temperature range (700–1250 K). In order to better understand the oxidation process of propyl acetate, a detailed kinetic mechanism consisting of 628 species involved in 3927 reversible reactions has been developed laying on previous works on esters oxidation and theoretical calculations performed in this study. These calculations compare well with the rate constant experimentally determined in our jet-Stirred Reactor for the molecular reaction: k = 1.292 × 10 13 exp ( − 25167 T ) ( s − 1 ) (700–1010 K).
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an experimental chemical kinetic study of the oxidation of diethyl ether in a jet Stirred Reactor and comprehensive modeling
Combustion and Flame, 2018Co-Authors: Sebastien Thion, Guillaume Dayma, Zeynep Serinyel, Maxence Lailliau, Philippe DagautAbstract:Abstract The oxidation of diethyl ether was studied experimentally in a jet-Stirred Reactor. Fuel-lean, stoichiometric and fuel-rich mixtures were oxidized at a constant fuel mole fraction (1000 ppm), at temperatures ranging from 450 to 1250 K, pressures of 1 and 10 atm, and constant residence time (70 and 700 ms, respectively). In total, six mixtures were tested at both pressures. Mole fraction profiles were obtained using gas chromatography and Fourier transform infrared spectrometry. The fuel mole fraction profiles, as well as some reaction intermediate and product profiles indicated strong low-temperature chemistry at high pressure. On the other hand, at atmospheric pressure this behavior was observed to a very small extent and only with the lean and stoichiometric mixtures. These data were compared to modeling results using literature mechanisms for diethyl ether oxidation. None of these predicted low-temperature reactivity under present conditions. Therefore, a kinetic mechanism is proposed in this study, based on recently computed kinetic parameters from literature. It shows good performances for representing the present experimental data as well as experimental data found in literature consisting of ignition delay times, laminar flame speeds and flame structure.
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an experimental study in a jet Stirred Reactor and a comprehensive kinetic mechanism for the oxidation of methyl ethyl ketone
Proceedings of the Combustion Institute, 2017Co-Authors: Guillaume Dayma, Sebastien Thion, Zeynep Serinyel, Pascal Dievart, Pierre Van Cauwenberghe, Philippe DagautAbstract:The first speciation data regarding the oxidation of methyl ethyl ketone (MEK) are presented. Fuel-lean, stoichiometric and fuel-rich mixtures were studied at constant fuel concentration (1000 ppm) in a jet Stirred Reactor at atmospheric and high pressure (10 atm). A detailed kinetic mechanism is proposed based on theoretical calculations at the G3//MP2/aug-cc-pVDZ level of theory. The new rate constants differ substantially from the estimations employed in the previous MEK submechanism available in the literature, and impact MEK oxidation pathways. The model was tested successfully against these new speciation data and other available data (ignition delay times, flame speeds, pyrolysis species profile). However, some deficiencies in the model were identified concerning methyl ketene and methyl vinyl ketone. Reaction path analyses are used to interpret the results.
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a chemical kinetic study of the oxidation of dibutyl ether in a jet Stirred Reactor
Combustion and Flame, 2017Co-Authors: Guillaume Dayma, Casimir Togbé, Sebastien Thion, Zeynep Serinyel, Philippe DagautAbstract:Abstract The oxidation of dibutyl-ether, a potential lignocellulosic biofuel was studied in a jet-Stirred Reactor. Fuel-lean, stoichiometric and fuel-rich mixtures were oxidized at a constant fuel mole fraction (1000 ppm), at temperatures ranging from 470 to 1250 K, pressures of 1 and 10 atm, and constant residence time (70 and 700 ms, respectively). The mole fraction profiles obtained through sonic probe sampling, gas chromatography and Fourier transform infrared spectrometry were used to develop a detailed kinetic mechanism for the oxidation of DBE. The carbon neighboring the ether group was found to be the most favorable site for H-abstraction reactions and the chemistry of the corresponding fuel radical drives the overall reactivity. The fuel concentration profiles indicated strong low-temperature chemistry at both pressures: two negative temperature coefficient regions were observed, notably on the 10 atm experiments. This unusual behavior was investigated by means of a rate of production analysis using the mechanism developed in this work. This analysis showed that the low-temperature reactivity stems from the low-temperature chemistry of the fuel and of smaller species such as C4H9 which are triggered at different threshold temperatures. The proposed mechanism shows good performances for representing the present experimental data, as well as ignition delay time and flame speed data available from the literature.
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experimental and detailed kinetic modeling study of cyclopentanone oxidation in a jet Stirred Reactor at 1 and 10 atm
Energy & Fuels, 2017Co-Authors: Sebastien Thion, Guillaume Dayma, Casimir Togbé, Zeynep Serinyel, Philippe DagautAbstract:Cyclopentanone oxidation was studied in a jet-Stirred Reactor at 1 and 10 atm and over the temperature range of 730–1280 K for fuel-lean (φ = 0.5), stoichiometric, and fuel-rich (φ = 2) mixtures. A total of 16 reaction intermediates and products were identified and quantified using online Fourier transform infrared spectrometry and offline gas chromatography. A kinetic submodel was developed, supported by theoretical calculations for the rate constants of hydrogen abstraction reactions by H atoms and OH and CH3 radicals at the MP2/aug-cc-pVDZ level of theory. The resulting model consisting of 343 species involved in 2065 reactions was used to simulate the present experiments and showed good agreement with the data. The main oxygenated intermediates are aldehydes, and cyclopentenone was also found to be an important species for cyclopentanone oxidation. The rate of production analyses showed that cyclopentanone is mainly consumed by a sequence of reactions producing CO and the but-1-en-4-yl radical. Unimol...
