In situ species diagnostics and kinetic study of plasma activated ethylene dissociation and oxidation in a low temperature flow reactor

Lefkowitz, Joseph K.; Uddi, Mruthunjaya; Windom, Bret; Lou, Guofeng; Ju, Yiguang

doi:10.1016/j.proci.2014.08.001

Cited by 72 publications

(57 citation statements)

References 45 publications

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“…Because the consumption of the reactants is almost entirely due to electron collision reactions and quenching of excited species (as will be discussed in the following sections), we can assume that the total electron collision rates are well modelled. The production of water is predicted to within 20% of the measured value, which is in excellent agreement considering the order-of-magnitude disagreement for water in our previous study of ethylene oxidation [14]. Figure 5b presents the other major products: carbon monoxide, carbon dioxide and hydrogen.…”

Section: Resultssupporting

confidence: 86%

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Species and temperature measurements of methane oxidation in a nanosecond repetitively pulsed discharge

Lefkowitz

Guo

Rousso

et al. 2015

Phil. Trans. R. Soc. A.

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109

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Speciation and temperature measurements of methane oxidation during a nanosecond repetitively pulsed discharge in a low-temperature flow reactor have been performed. Measurements of temperature and formaldehyde during a burst of pulses were made on a time-dependent basis using tunable diode laser absorption spectroscopy, and measurements of all other major stable species were made downstream of a continuously pulsed discharge using gas chromatography. The major species for a stoichiometric methane/oxygen/helium mixture with 75% dilution are H 2 O, CO, CO 2 , H 2 , CH 2 O, CH 3 OH, C 2 H 6 , C 2 H 4 and C 2 H 2 . A modelling tool to simulate homogeneous plasma combustion kinetics is assembled by combining the ZDPlasKin and CHEMKIN codes. In addition, a kinetic model for plasma-assisted combustion (HP-Mech/plasma) of methane, oxygen and helium mixtures has been assembled to simulate the measurements. Predictions can accurately capture reactant consumption as well as production of the major product species. However, significant disagreement is found for minor species, particularly CH 2 O and CH 3 OH. Further analysis revealed that the plasma-activated low-temperature oxidation pathways, particularly those involving CH 3 O 2 radical reactions and methane reactions with O( 1 D), are responsible for this disagreement.

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Section: Resultssupporting

confidence: 86%

“…The experimental set-up has been previously described in [14,[32][33][34]. A diagram of the set-up can be found in figure 1.…”

Section: Experimental Set-up (A) Plasma Reactormentioning

confidence: 99%

Species and temperature measurements of methane oxidation in a nanosecond repetitively pulsed discharge

Lefkowitz

Guo

Rousso

et al. 2015

Phil. Trans. R. Soc. A.

Self Cite

109

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“…In order to understand the kinetic pathways of low temperature oxidation in plasma assisted combustion, experimental and numerical studies of low temperature methane [19] oxidation in a nanosecond repetitively pulsed (NRP) discharge have been carried out [26,27]. The experimental setup is shown in Fig.…”

Section: Low Temperature Oxidation Of Methane In a Flow Reactor With mentioning

confidence: 99%

“…Figure 16 shows the comparisons between model predictions and experimental results of the time-resolved concentrations of C 2 H 2 , CH 4 , and H 2 O formation. It is clear that HPMech [27,34], which is developed particularly for low temperature and high pressure fuel oxidation based on direct experimental measurements and/or ab initio quantum chemistry calculations of the elementary reaction rate constants without global mechanism optimization, reproduces well the measured species time history with only slight under-prediction of C 2 H 2 . However, USC-Mech II [42] over-predicts H 2 O formation by one order (Fig.…”

Section: Low Temperature Oxidation Of Methane In a Flow Reactor With mentioning

confidence: 99%

Plasma Assisted Low Temperature Combustion

Lefkowitz

Reuter

et al. 2015

Plasma Chem Plasma Process

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146

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This paper presents recent kinetic and flame studies in plasma assisted low temperature combustion. First, the kinetic pathways of plasma chemistry to enhance low temperature fuel oxidation are discussed. The impacts of plasma chemistry on fuel oxidation pathways at low temperature conditions, substantially enhancing ignition and flame stabilization, are analyzed base on the ignition and extinction S-curve. Secondly, plasma assisted low temperature ignition, direct ignition to flame transition, diffusion cool flames, and premixed cool flames are demonstrated experimentally by using dimethyl ether and n-heptane as fuels. The results show that non-equilibrium plasma is an effective way to accelerate low temperature ignition and fuel oxidation, thus enabling the establishment of stable cool flames at atmospheric pressure. Finally, the experiments from both a nonequilibrium plasma reactor and a photolysis reactor are discussed, in which the direct measurements of intermediate species during the low temperature oxidations of methane/ methanol and ethylene are performed, allowing the investigation of modified kinetic pathways by plasma-combustion chemistry interactions. Finally, the validity of kinetic mechanisms for plasma assisted low temperature combustion is investigated. Technical challenges for future research in plasma assisted low temperature combustion are then summarized.

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“…The state of the art approach to model the chemistry of plasma assisted combustion is to use a combined air plasma chemistry and conventional kinetic mechanism of combustion [39]. However, for low temperature plasma assisted ignition (300-900 K) [40], the existing air plasma mechanism together with combustion mechanisms (e.g. HP Mech [40] and USC-Mech [41]) fails to predict the species production even for H 2 O and CH 4 in nanosecond repetitively pulsed discharge for ethylene/oxygen mixtures.…”

Section: Igniɵon Limitmentioning

confidence: 99%