Diagnostics of a Hydrocarbon Plasma Jet Using the A<sup>2</sup>Δ-X<sup>2</sup>Π System of CH

Koulidiati, Jean; Czernichowski, A.; Beulens, JJ; Schram, DC Daan

doi:10.12693/aphyspola.94.3

Cited by 2 publications

(2 citation statements)

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“…The luminous zone of the gliding electric discharges, as well as part of the wall of the zone, can be observed through a glass /24/ in order to verify the proper operation of the reactor and to determine the temperature in the compartment /15a/. An important information may be derived from the plasma emission spectrum (Koulidiati et al, 1998). The conversion of a NG is generally sufficient with a single run through a single reactor.…”

Section: Pox Conversionmentioning

confidence: 99%

Glidarc Assisted Preparation of the Synthesis Gas from Natural and Waste Hydrocarbons Gases

Czernichowski

2001

Oil & Gas Science and Technology - Rev. IFP

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Résumé -Arcs glissants pour générer le gaz de synthèse à partir des hydrocarbures légers -Cet article passe en revue l'utilisation des plasmas comme milieu activateur d'une oxydation partielle du gaz naturel ou d'un gaz associé pour produire le gaz de synthèse (H 2 + CO). Cette matière première peut être également convertie en syngaz dans un processus de reformage à la vapeur d'eau (steam reforming) assisté par plasmas qui, dans ce cas, exercent un rôle de catalyseurs et, en même temps, fournissent l'énergie très active nécessaire à une telle réaction, endothermique cette fois. Enfin, les mêmes plasmas peuvent être utiles pour effectuer une autre réaction endothermique de conversion directe des gaz hydrocarbonés contenant de fortes teneurs en CO 2 (tels que le biogaz ou certains gaz naturels acides) en syngaz.Deux réacteurs à plasma à l'échelle du laboratoire sont utilisés pour tester les conversions : un réacteur à arc contrôlé et un réacteur plus récent, à multiples arcs glissants (GlidArc). Dans ce dernier, opérant jusqu'à une pression de 0,4 MPa, on obtient une conversion quasi totale du gaz naturel (1,3 m 3 (n)/h) via oxydation partielle -avec une dépense d'énergie de seulement 0,11 kWh pour 1 m 3 (n) de syngaz de rapport molaire H 2 /CO proche de 2 -en utilisant l'oxygène pur comme réactif. Avec l'air enrichi (45 % O 2 ), la dépense est de 0,24 kWh.Un pilote de 100 m 3 (n)/h de syngaz est actuellement testé sur un champ de gaz naturel.Mots-clés : GlidArc, arc contrôlé, gaz de synthèse, gaz naturel, gaz associé, biogaz, réacteurs plasma, décharges électriques, carburants synthétiques propres, oxydation partielle, reformage, Fischer-Tropsch. Abstract -GlidArc Assisted Preparation of the Synthesis Gas from Natural and Waste Hydrocarbons Gases -This article reviews utilisation of plasmas as activation media for the partial oxidation of natural or associated gases to produce synthesis gas (H 2 + CO). These feedstocks can also be converted into

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Section: Pox Conversionmentioning

confidence: 99%

Glidarc Assisted Preparation of the Synthesis Gas from Natural and Waste Hydrocarbons Gases

Czernichowski

2001

Oil & Gas Science and Technology - Rev. IFP

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“…Spectral simulation in this electronic system can be done, including the possibility of modifying many parameters interactively. The distribution among vibrational levels and the rotational distribution in each vibrational level are assumed to follow thermal population with characteristic vibrational temperature T vib and rotational temperature T rot [27,28].…”

Section: Resultsmentioning

confidence: 99%

Determination of the number densities of CH(X2Π) and CH(A2Δ) radicals in a DC cascaded arc discharge plasma

Wang

et al. 2015

Appl. Phys. B

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radical-based chemistry generally dominates in any eventual material processing in the plasma jet.The CH radical is a common intermediate in reactive chemical systems with hydrocarbons [6]. Monitoring CH provides an insight into the reaction mechanism. CH radicals and C atoms contribute to the experimentally observed high and nonuniform diamond growth rates in the highpower Bristol reactor [7]. The level of CH concentration agreement between the model prediction and the experimental measurement can be used to test model predictions of hydrocarbon chemistry [8]. CH also is a probe species to determine the chemical erosion of carbon-based materials in divertor [9].Optical emission spectroscopy (OES) is arguably the simplest and most straightforward means to investigate the CH behavior in the plasma. The OES signal is proportional to the population density of the upper state, and the interpretation of OES data is complicated which needs a proper understanding of the various species excitation and de-excitation processes, especially when the plasma does not close to local thermodynamic equilibrium (LTE). Generally, the ground electronic state radicals and molecules are inevitably present in higher concentrations than their electronically excited counterparts and dominate the thin film deposition [10]. Thus, it is necessary to measure the majority species populating ground and low-lying electronic states.To diagnose the ground state, absorption spectroscopy is a preferred approach. Cavity ring-down spectroscopy (CRDS) [11] provides the diagnostic of choice to obtain the absolute number densities without the need for additional calibration standards. The technique measures the time decay of a laser pulse trapped in a high-finesse optical cavity. Effectively, it is a multi-pass technique in which the optical path length may be tens of kilometers. Thus, it is a versatile, highly sensitive, linear absorption technique.Abstract A combination of optical emission spectroscopy (OES) and cavity ring-down spectroscopy (CRDS) has enabled to determinate the number densities of CH(A 2 Δ) and CH(X 2 Π) radicals simultaneously in a cascaded arc plasma reactor operating with a CH 4 /Ar mixture. It is found that the number density of CH(A 2 Δ) radical increases with discharge current at first and then decreases. However, the number density of CH(X 2 Π) radical decreases with discharge current when the rate of CH 4 flow to total flow is lower than 1 %, while it increases slightly with discharge current when the rate is 1.5 %. The results reveal that CH radicals are deviation from excitation equilibrium. Although OES is the simplest and most straightforward means to investigate the CH radical behavior, it is not enough to provide the information of the CH(X 2 Π) number density, and additional methods, such as CRDS, are needed in the cascaded arc plasma jet.

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Diagnostics of a Hydrocarbon Plasma Jet Using the A²Δ-X²Π System of CH

Cited by 2 publications

References 11 publications

Glidarc Assisted Preparation of the Synthesis Gas from Natural and Waste Hydrocarbons Gases

Glidarc Assisted Preparation of the Synthesis Gas from Natural and Waste Hydrocarbons Gases

Determination of the number densities of CH(X2Π) and CH(A2Δ) radicals in a DC cascaded arc discharge plasma

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Diagnostics of a Hydrocarbon Plasma Jet Using the A2Δ-X2Π System of CH

Cited by 2 publications

References 11 publications

Glidarc Assisted Preparation of the Synthesis Gas from Natural and Waste Hydrocarbons Gases

Glidarc Assisted Preparation of the Synthesis Gas from Natural and Waste Hydrocarbons Gases

Determination of the number densities of CH(X2Π) and CH(A2Δ) radicals in a DC cascaded arc discharge plasma

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Diagnostics of a Hydrocarbon Plasma Jet Using the A²Δ-X²Π System of CH