Sensitizing effects of NOx on CH4 oxidation at high pressure

Rasmussen, Christian Lund; Rasmussen, Anja Egede; Glarborg, Peter

doi:10.1016/j.combustflame.2008.01.012

Cited by 127 publications

(72 citation statements)

References 130 publications

(178 reference statements)

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“…in the measurement equipment, we were unable to detect any N-intermediates and thus it is not possible to conclude on the NO x reduction trend. However, Rasmussen et al [13] recently reported a similar reduction in NO x for the CH 4 /O 2 /NO x system, increasing with pressure from 20 to 100 bar. The observed pressure dependence could indicate that the NO removal is initiated by formation of a thermally stable adduct.…”

Section: Resultsmentioning

confidence: 80%

“…The mechanism used for the modeling study, as well as the corresponding thermodynamic properties, was drawn from previous high-pressure work on conversion of CO/H 2 /O 2 /NO x [11], CH 4 /C 2 H 6 /O 2 [12], and CH 4 /O 2 /NO x [13]. Recently, it was updated to describe C 2 H 4 oxidation at high pressure, with particular emphasis on a number of oxygenated C 2 -species important under low-temperature conditions [1].…”

Section: Chemical Kinetic Modelmentioning

confidence: 99%

“…In the absence of direct measurements of k 2b and k 3b , we have applied estimates for the reverse steps by analogy to the corresponding reactions of CH 3 [22]. After initiation, the major oxidation path for C 2 [23], were drawn from Rasmussen et al [13].…”

Section: Chemical Kinetic Modelmentioning

confidence: 99%

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High pressure oxidation of C2H4/NO mixtures

Giménez-López

Alzueta

Rasmussen

et al. 2011

Proceedings of the Combustion Institute

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An experimental and kinetic modeling study of the interaction between C 2 H 4 and NO has been performed under flow reactor conditions in the intermediate temperature range (600-900 K), high pressure (60 bar), and for stoichiometries ranging from reducing to oxidizing conditions. The main reaction pathways of the C 2 H 4 /O 2 /NO x conversion, the capacity of C 2 H 4 to remove NO, and the influence of the presence of NO x on the C 2 H 4 oxidation are analyzed. Compared to the C 2 H 4 /O 2 system, the presence of NO x shifts the onset of reaction 75-150 K to lower temperatures. The mechanism of sensitization involves the reaction HOCH 2 CH 2 OO + NO → CH 2 OH + CH 2 O + NO 2 , which pushes a complex system of partial equilibria towards products. This is a confirmation of the findings of Doughty et al. [Proc. Combust. Inst. 26 (1996) 589-596] for a similar system at atmospheric pressure. Under reducing conditions and temperatures above 700 K, a significant fraction of the NO x is removed. This removal is partly explained by the reaction C 2 H 3 + NO → HCN + CH 2 O. However, a second removal mechanism is active in the 700-850 K range, which is not captured by the chemical kinetic model. With the present thermochemistry and kinetics, neither formation of nitro-hydrocarbons

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Section: Resultsmentioning

confidence: 80%

Section: Chemical Kinetic Modelmentioning

confidence: 99%

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High pressure oxidation of C2H4/NO mixtures

Giménez-López

Alzueta

Rasmussen

et al. 2011

Proceedings of the Combustion Institute

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“…The mechanism used in the present study is based on the atmospheric pressure methanol schemes by the authors [14,15], drawing also on previous high pressure work on oxidation of CO and CH 4 [18,20,21]. The methanol subset has been updated with results from recent theoretical work [22][23][24] and from ab initio calculations and RRKM analysis made as part of the present work on reactions of CH 2 OH and CH 3 O (dissociation, isomerization, reaction with O 2 ).…”

Section: Chemical Kinetic Modelmentioning

confidence: 99%

Experimental and Kinetic Modeling Study of Methanol Ignition and Oxidation at High Pressure

Aranda

Christensen

Alzueta

et al. 2013

Int J of Chemical Kinetics

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A detailed chemical kinetic model for oxidation of CH 3 OH at high pressure and intermediate temperatures has been developed and validated experimentally. Ab initio calculations and RRKM analysis were used to obtain rate coefficients for key reactions of CH 2 OH and CH 3 O (dissociation, isomerization, reaction with O 2 ). The experiments, involving CH 3 OH/O 2 mixtures diluted in N 2 , were carried out in a high pressure flow reactor at 600-900 K and 20-100 bar, varying the reaction stoichiometry from very lean to fuel-rich conditions. Under the conditions studied, the onset temperature for methanol oxidation was not dependent on the stoichiometry, while increasing pressure shifted the ignition temperature towards lower values. Model predictions of the present experimental results, as well as Rapid Compression Machine (RCM) data from the literature, were generally satisfactory. The governing reaction pathways have been outlined based on calculations with the kinetic model. Unlike what has been observed for unsaturated hydrocarbons, the oxidation 2 pathways for CH 3 OH under the investigated conditions were very similar to those prevailing at higher temperatures and lower pressures. At the high pressures, the modeling predictions for onset of reaction were particularly sensitive to the CH 3 OH+HO 2 ⇌CH 2 OH+H 2 O 2 reaction.

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“…The starting mechanism was drawn from the recent study of NH 3 -doped CH 4 /O 2 /Ar flames [13]. This mechanism relied on work on the oxidation of C 1 /C 2 -hydrocarbons [55,56], NH 3 [57], and HCN [3], as well as interactions of these components [11,55,58,59]. Thermal NO and prompt NO formation mechanisms [1,60] are not important in the present flames due to the high concentrations of amines.…”

Section: Reaction Mechanismmentioning

confidence: 99%

Fuel-nitrogen conversion in the combustion of small amines using dimethylamine and ethylamine as biomass-related model fuels

Lucassen

Zhang

Warkentin

et al. 2012

Combustion and Flame

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Laminar premixed flames of the two smallest isomeric amines, dimethylamine and ethylamine, were investigated under one-dimensional low-pressure (40 mbar) conditions with the aim to elucidate pathways that may contribute to fuel-nitrogen conversion in the combustion of biomass. For this, identical flames of both fuels diluted with 25% Ar were 2 studied for three different stoichiometries (Φ=0.8, 1.0, and 1.3) using in situ molecular-beam mass spectrometry (MBMS). Quantitative mole fractions of reactants, products and numerous stable and reactive intermediates were determined by electron ionization (EI) MBMS with high mass resolution to separate overlapping features from species with different heavy elements by exact mass. Species assignment was assisted by using single-photon vacuum- We attempted to analyze the major pathways in the two flames with a detailed combustion model developed for this purpose. For this, thermochemical values for a number of intermediates had to be determined from quantum chemistry calculations. Also, specific sets of reactions were incorporated for the two fuels. While many trends seen in the experiments can be successfully reproduced by the simulations, additional efforts may be needed to reliably describe the fuel-nitrogen chemistry in the combustion of biomass-related model fuels with amine functions.

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Sensitizing effects of NOx on CH4 oxidation at high pressure

Cited by 127 publications

References 130 publications

High pressure oxidation of C2H4/NO mixtures

High pressure oxidation of C2H4/NO mixtures

Experimental and Kinetic Modeling Study of Methanol Ignition and Oxidation at High Pressure

Fuel-nitrogen conversion in the combustion of small amines using dimethylamine and ethylamine as biomass-related model fuels

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