Numerical simulation of stoichiometric premixed flames burning CH3Cl / CH4 / air mixtures at atmospheric pressure with a full and short reaction mechanism and comparison of the flame speeds with experimental results

Lee, K.Y.; Yang, Ming; Puri, Ishwar K.

doi:10.1016/0010-2180(93)90153-t

Cited by 29 publications

(8 citation statements)

References 19 publications

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“…Reactions of Cl and H atoms with chlorinated hydrocarbons (CHCs) are among the most important and sensitive reactions in the combustion and incineration of CHCs. − In CHC/O 2 and CHC/hydrocarbon/O 2 flames, reactions of Cl and H atoms with CHCs together with unimolecular decomposition are the major channels of consumption of CHCs. − ,− As a part of a project directed at the elucidation of the kinetics of these important reactions, we recently reported − the results of our experimental and computational studies of the reactions of H and Cl atoms with methane and chlorinated methanes, and the reactions of H atoms with ethane and three chlorinated ethanes. In the current work, we extend such kinetic studies to the reactions of Cl atoms with ethane and two chlorinated ethanes (C 2 H 5 Cl and CH 3 CHCl 2 ) conducted over wide ranges of temperatures: The numbers in parentheses indicate the experimental temperature ranges of the current work.…”

Section: Introductionmentioning

confidence: 99%

Kinetics of Reactions of Cl Atoms with Ethane, Chloroethane, and 1,1-Dichloroethane

2003

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Reactions of Cl atoms with ethane (1), chloroethane (2), and 1,1-dichloroethane (3) were studied experimentally with the discharge flow/resonance fluorescence technique over wide ranges of temperatures and at pressures between 2.3 and 9.2 Torr. Results of earlier investigations of the reactions of Cl atoms with ethane and chloroethanes are analyzed and compared with the results of the current work. The rate constants of the reaction of Cl atoms with ethane obtained in the current study (k 1 ) (4.91 × 10 -12 )T 0.47 exp(-82 K/T) cm 3 molecule -1 s -1 , 299-1002 K) agree with the results of earlier determinations. Combination of the temperature dependence of k 1 obtained in the current work with the existing (mostly at lower temperatures) literature data results in the expression k 1 ) (7.23 × 10 -13 )T 0.70 exp(+117 K/T) cm 3 molecule -1 s -1 (203-1400 K). Rate constants of the reactions of Cl atoms with chloroethane and 1,1-dichloroethane demonstrate different temperature dependences in the low-temperature (room temperature to 378 K) and the high-temperature (484-810 K) regions. The differences are due to the regeneration of Cl atoms at higher temperatures as a consequence of the fast thermal decomposition of radical products with a chlorine atom in the β position. This information enables quantitative differentiation between the site-specific reaction channels. The results of the current study, combined with those of earlier relative-rate experiments, were used to derive expressions for the temperature dependences of the rates of the site-specific abstraction channels: k 2a (T) ) (2.76 ( 0.28) × 10 -11 exp(-455 ( 44 K/T) (296-810 K), k 2b (T) ) (1.92 ( 0.47) × 10 -11 exp(-789 ( 84 K/T) (296-378 K), k 3a (T) ) (1.46 ( 0.21) × 10 -11 exp(-733 ( 58 K/T) (293-810 K), and k 3b (T) ) (2.98 ( 1.42) × 10 -11 exp(-1686 ( 160 K/T) (293-378 K) cm 3 molecule -1 s -1 , where channels a and b signify abstraction of hydrogen atoms in the R and β positions, respectively.

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Section: Introductionmentioning

confidence: 99%

Kinetics of Reactions of Cl Atoms with Ethane, Chloroethane, and 1,1-Dichloroethane

2003

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“…Key to the understanding of CHC combustion and its products is fundamental knowledge of the mechanisms, specific pathways, and rate constants of the important elementary reactions involved. Among the most important and sensitive reactions involved in the currently used mechanisms of the combustion of chlorinated hydrocarbons are the reactions of Cl and H atoms with the main compounds that are being burned. − In CHC/O 2 and CHC/hydrocarbon/O 2 flames, reactions of Cl and H atoms with CHCs together with unimolecular decomposition are the major channels of consumption of CHCs. − ,− The results of numerical simulations demonstrate that the rates of CHC destruction and the concentrations of active species are highly sensitive to the rates of Cl + CHC and H + CHC reactions.…”

Section: Introductionmentioning

confidence: 99%

Kinetics of Reactions of Cl Atoms with Methane and Chlorinated Methanes

2002

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The reactions of Cl atoms with methane and three chlorinated methanes (CH 3 Cl, CH 2 Cl 2 , and CHCl 3 ) have been studied experimentally using the discharge flow/resonance fluorescence technique over wide ranges of temperature and at pressures between 1.4 and 8.8 Torr. The rate constants were obtained in direct experiments as functions of temperature: k 1 (Cl + CH 4 ) ) 1.30 × 10 -19 T 2.69 exp(-497 K/T) (295-1104 K), k 2 (Cl + CH 3 Cl) ) 4.00 × 10 -14 T 0.92 exp(-795 K/T) (300-843 K), k 3 (Cl + CH 2 Cl 2 ) ) 1.48 × 10 -16 T 1.58 exp(-360 K/T) (296-790 K), and k 4 (Cl + CHCl 3 ) ) 1.19 × 10 -16 T 1.51 exp(-571 K/T) (297-854 K) cm 3 molecule -1 s -1 . Results of earlier experimental and theoretical studies of the reactions of Cl atoms with methane and chloromethanes are analyzed and compared with the results of the current investigation. It is demonstrated that the existing theoretical models of reactions 2-4 are in disagreement with the experiments and thus are not suitable for use in extrapolating the experimental results to conditions outside the experimental ranges. Thus, no better alternative to the use of experimental modified Arrhenius fits can be proposed at this time. A transition-state theory model of reaction 1 (Cl + CH 4 ) was created on the basis of ab initio calculations and analysis of the experimental data and was used to extrapolate the latter to temperatures outside the experimental ranges. The model results in the expression k 1 (Cl + CH 4 ) ) 5.26 × 10 -19 T 2.49 exp(-589 K/T) cm 3 molecule -1 s -1 (200-3000 K) for the temperature dependence of the rate constant. Temperature dependences of the rate constants of the reverse R + HCl f Cl + RH reactions were derived on the basis of the experimental data, modeling, and thermochemical information.

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“…Fundamental knowledge of mechanisms, specific pathways, and rate constants of important elementary reactions is of key importance to the success of such modeling. Among the most important and sensitive reactions involved in the currently used mechanisms of CHC combustion are the reactions of H and Cl atoms with the main compounds that are being burned. − In CHC/O 2 and CHC/hydrocarbon/O 2 flames, reactions of Cl and H atoms with CHCs together with unimolecular decomposition are the major channels of consumption of CHCs. − ,− The results of numerical kinetic simulations demonstrate that the rates of CHC destruction and concentrations of active species are highly sensitive to the rates of H + CHC and Cl + CHC reactions.…”

Section: Introductionmentioning

confidence: 99%

Computational Study of the Reactions of H Atoms with Chlorinated Alkanes. Isodesmic Reactions for Transition States

Knyazev

2002

J. Phys. Chem. A

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Reactions of H atoms with methane, ethane, and chlorinated methanes and ethanes were studied by computational methods. An approach to estimating reaction rate constants based on the use of isodesmic reactions for transition states was developed and implemented. Reactions of H atoms with CH4 and CCl4 (clear cases of H and Cl abstraction, respectively) were used as reference reactions. Rate constants of all other reactions from the series were calculated using the isodesmic reactions approach. For the seven reactions for which directly obtained experimental data are available, the resultant calculated temperature dependences of the rate constants demonstrate agreement with experiment. Average deviations between calculations and experiment are 17−24%, depending on the quantum chemical method used, although channel-specific rates show larger divergence. Rate constants of all 30 reaction members of the H + chloromethane and H + chloroethane classes are calculated as functions of temperature using the described approach. Individual channels of H and Cl abstraction and the corresponding reverse reactions are quantitatively characterized. In a separate part of the investigation, it is demonstrated that correlations between the energy barriers and reaction enthalpies do not provide a good predictive tool for evaluating temperature dependences of the reaction rate constants of the H + chloroalkanes class.

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Numerical simulation of stoichiometric premixed flames burning CH3Cl / CH4 / air mixtures at atmospheric pressure with a full and short reaction mechanism and comparison of the flame speeds with experimental results

Cited by 29 publications

References 19 publications

Kinetics of Reactions of Cl Atoms with Ethane, Chloroethane, and 1,1-Dichloroethane

Kinetics of Reactions of Cl Atoms with Ethane, Chloroethane, and 1,1-Dichloroethane

Kinetics of Reactions of Cl Atoms with Methane and Chlorinated Methanes

Computational Study of the Reactions of H Atoms with Chlorinated Alkanes. Isodesmic Reactions for Transition States

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