Methane Conversion: a Case Study for Simplification of Plasma Chemistry Models by the Omission of Charged Species

Kovács, Tamás

doi:10.1007/s11090-009-9209-8

Cited by 12 publications

(5 citation statements)

References 7 publications

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“…In arc discharge, the mixture of neutral and ionic species is at thermal equilibrium. Kovács et al [59] have demonstrated that at a temperature higher that 4000K the reactivity of ionic species is considerably lower than that of neutral species. Therefore, the decomposition of methane is driven by thermal activation because high temperature provides sufficient energy for the activation of the dehydrogenation reaction.…”

Section: Plasma Chemistry For Thermal Plasmamentioning

confidence: 99%

The panorama of plasma-assisted non-oxidative methane reforming

Scapinello

Delikonstantis

Stefanidis

2017

Chemical Engineering and Processing: Process Intensification

150

151

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Methane is an important raw material for fuel and commodity chemicals production. Energyintensive steam methane catalytic reforming in gas-fired furnaces is the main industrial process for methane conversion to synthesis gas and further to other chemicals. Methane conversion by means of non-thermal plasma technologies has attracted attention in the last years, as no pre-heating of the feedstream at high temperatures is needed. Electric energy is consumed in producing energetic electrons for molecule bonds breaking, instead of gas heating, thereby overcoming the disadvantages of high operational temperatures. In this work, after introducing plasma classification and plasma chemistry, a comprehensive review of literature papers on non-thermal plasma-assisted methane coupling in the period 2010-2016 is presented and the best results that have been obtained with all different kinds of non-thermal plasma techniques are reported. Finally, as the energy cost is the main cost driver of the process after the raw material cost, comparison among all plasma techniques used for methane coupling is performed in terms of specific energy requirement to crack a mole of methane (SER, kJ/molCH4), efficiency (η %) and energy requirement to produce a mole of target product (ER, either kJ/molC2H2 or kJ/molC2H4). This is followed by a comparison between plasma-driven and thermal energy-driven methane coupling.

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Section: Plasma Chemistry For Thermal Plasmamentioning

confidence: 99%

The panorama of plasma-assisted non-oxidative methane reforming

Scapinello

Delikonstantis

Stefanidis

2017

Chemical Engineering and Processing: Process Intensification

150

151

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“…Arrhenius parameters were adopted from the NIST database [23], while there for the reverse reactions they were calculated by the MECHMOD [24]. In the mechanismdue to the low concentrations of the ionic species and the small reaction rates, no ionic species were considered [25].…”

Section: Simulationsmentioning

confidence: 99%

CCl4 Decomposition in RF Thermal Plasma in Inert and Oxidative Environments

Kovács

Turányi

Szépvölgyi

2010

Plasma Chem Plasma Process

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The decomposition of carbon tetrachloride was investigated in an RF inductively coupled thermal plasma reactor in inert CCl 4 -Ar and in oxidative CCl 4 -O 2 -Ar systems, respectively. The exhaust gases were analyzed by gas chromatography-mass spectrometry. The kinetics of CCl 4 decomposition at the experimental conditions was modeled in the temperature range of 300-7,000 K. The simulations predicted 67.0 and 97.9% net conversions of CCl 4 for CCl 4 -Ar and for CCl 4 -O 2 -Ar, respectively. These values are close to the experimentally determined values of 60.6 and 92.5%. We concluded that in RF thermal plasma much less CCl 4 reconstructed in oxidative environment than in an oxygen-free mixture.

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“…In the thermal plasma environment, chemically active species can be generated through a combination of thermal activation and electron collisions [55]. However, Kovács et al [56] indicated that, in thermal plasma, the reactivity of ionic species is significantly lower compared to neutral species (a result of their low concentration). Consequently, the decomposition of methane is primarily governed by thermal activation, wherein the high energy initiates the dehydrogenation reaction per Equations ( 10)-( 13).…”

Section: Methane Pyrolysis Mapping For Graphene Productionmentioning

confidence: 99%

In Situ Graphene Synthesis Study in Inductively Coupled Radiofrequency Thermal Plasma Reactor Using Methane Precursor

Mahmoud,

Gitzhofer,

Blanchard

et al. 2023

Plasma Chem Plasma Process

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While numerous studies are available on methane pyrolysis chemical kinetics and the effect of plasma parameters on graphene synthesis, a comprehensive understanding of the formation mechanism remains elusive without in situ analysis. This study aims to utilize a sampling probe for the first time to collect graphene locally on transmission electron microscopy grids and perform a localized sampling and analysis of the gas composition (during graphene synthesis) using mass spectrometry. This technique provides a 3D tracking of methane pyrolysis in radiofrequency inductively coupled thermal plasma reactor for graphene production. Response surface methodology based on central composite design is employed to obtain a 3D visualization of the synthesis process. Quadratic and cubic models are developed, followed by comprehensive analysis of variance. A comparison of the gas-phase chemistry resulting from the in situ measurements with thermodynamic equilibrium calculations reveals that the process is controlled by thermochemical kinetics. H2, C2H2, C2H4, C3H6, and C6H6, as well as residual CH4, are the main hydrocarbons found in the graphene nucleation zone. The primary pathway for methane pyrolysis and graphene formation in RF plasma is through H2 and C2 hydrocarbons, while graphene nucleation and growth reactions are terminated 350 mm from the plasma torch nozzle exit. Morphology, quality, mean particle size, and the number of layers of the produced graphene samples, locally collected at different locations by 3D axisymmetric probe scanning, were investigated using TEM, highresolution TEM imaging, and Raman analysis. The gathered information is highly valuable for plasma reactor design.

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Methane Conversion: a Case Study for Simplification of Plasma Chemistry Models by the Omission of Charged Species

Cited by 12 publications

References 7 publications

The panorama of plasma-assisted non-oxidative methane reforming

The panorama of plasma-assisted non-oxidative methane reforming

CCl4 Decomposition in RF Thermal Plasma in Inert and Oxidative Environments

In Situ Graphene Synthesis Study in Inductively Coupled Radiofrequency Thermal Plasma Reactor Using Methane Precursor

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