The repetitive microwave discharge as a catalyst for a chemical reaction

Babaritskii, A. I.; Gerasimov, E. N.; Demkin, S. A.; Zhivotov, V. K.; Knizhnik, Andrey A.; Потапкин, Б. В.; Rusanov, V. D.; Ryazantsev, E. I.; Смирнов, Р. В.; Sholin, G. V.

doi:10.1134/1.1325021

Cited by 15 publications

(11 citation statements)

References 3 publications

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“…There are several publications about the plasma-catalyst hybrid reaction for methane reforming, where gas components does not necessarily represent thermal equilibrium gas mixtures. 15,16 However, we point out that catalyst temperature was not well-evaluated in these studies, although relatively large specific energy density (input power divided by total flow rate) was applied: catalyst temperature must be carefully evaluated for better correlation with gas composition. In addition, as far as MSR is concerned, methanation of CO 2 (reverse reaction) was sufficiently faster than MSR (forward reaction), which was experimentally demonstrated in the previous study.…”

Section: Resultsmentioning

confidence: 99%

Reaction Enhancement Mechanism of the Nonthermal Discharge and Catalyst Hybrid Reaction for Methane Reforming

2008

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The reaction enhancement mechanism of methane steam reforming (MSR) in the nonthermal discharge and catalyst hybrid reaction is presented. Coke deposited on Al2O3-supported Ni catalyst was investigated using temperature-programmed oxidation (TPO) analysis and micro-Raman spectroscopy. Although methane conversion in the hybrid reaction is greater than that of normal catalytic reforming, the normal reaction deposited 5 times more coke than the hybrid reaction. Raman spectroscopy revealed that the superposition of the nonthermal discharge on catalysts produced less graphitized coke compared to the normal catalytic reaction, by which it is easily removed by H2O during steam reforming. Excited species produced by nonthermal discharge are so reactive that their reaction is completed only on the pellet surface: coke formation in the catalyst pore was only slightly detectable. In contrast, large amounts of coke were detected from the surface and catalyst pores in the normal reaction. In the hybrid reaction, CH4 and H2O are primarily excited by electron impact. Therefore, methane dehydrogenation followed by coke oxidation is promoted, resulting in a small amount of coke formation with greater methane conversion than in the normal reaction. The results are well-correlated with Arrhenius plot analysis of the overall forward rate constant for MSR in the hybrid reaction.

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Section: Resultsmentioning

confidence: 99%

Reaction Enhancement Mechanism of the Nonthermal Discharge and Catalyst Hybrid Reaction for Methane Reforming

2008

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“…Kogelschatz et al [21,22] recently reviewed novel applications of DBD. Extensive research works on greenhouse gas conversion to produce carbon and hydrogen [23], oxygenates [24][25][26], synthesis gas (H 2 +CO) [27][28][29] and higher hydrocarbons [30][31][32] by the combination of plasma and zeolite catalysts have been reported. Eliasson and Kogelschatz [33] studied the hydrogenation of CO 2 to methanol in a DBD with and without a catalyst in the DBD gap.…”

Section: Dielectric-barrier Discharge (Dbd) Plasmamentioning

confidence: 99%

Process intensification in gas-to-liquid reactions: plasma promoted Fischer-Tropsch synthesis for hydrocarbons at low temperatures and ambient pressure

Al-Harrasi¹,

Zhang²,

Akay³

2013

Green Processing and Synthesis

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The Fischer-Tropsch synthesis (FTS) for the conversion of carbon monoxide and hydrogen to higher hydrocarbons was investigated over a supported Cu/Co catalyst promoted by dielectric-barrier discharges (DBDs) at relatively low temperatures and ambient pressure. The effect of plasma power, operation pressure, and H 2 /CO molar ratio on the activity and selectivity of the catalyst in a DBD reactor were studied. The fresh and used catalyst samples were characterized by scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray, and X-ray diffraction. We also used DBDs in catalyst preparation as a technique to enhance metal distribution on the catalyst support. The present study reveals that plasma can promote the FTS over a Cu/Co-based catalyst at low temperatures and ambient pressure. The formation of methane was strongly suppressed in plasma. In contrast to conventional FTS, CO conversion was higher at low operating pressure than that at higher pressure in the DBD-promoted FTS, which indicates the presence of a new reaction path for FTS.

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“…Microwave technology has been widely used to accelerate chemical reactions (Budarin et al, 2004;Liu et al, 2004;Babaritskii et al, 2003). In contrast to conventional heating, microwave assisted or hybrid heating yields a rapid heating and direct heating of the selected components of materials (Adachi et al, 2005;Chevalier et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

Effect of PEG number on dielectric properties of paraffin‐based PEG polymers at microwave frequencies

Pittini

Daneshvari

Leparoux

et al. 2008

COMPEL - The International Journal for Computation and Mathematics in Electrical and Electronic Engineering

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Purpose -To investigate the effect of poly ethylene glycol (PEG) chain length on the dielectric properties of paraffin-based PEG polymers (H(CH 2 ) n -(OCH 2 CH 2 ) m OH) from both experimental and analytical approach. Design/methodology/approach -Dielectric constant studies of paraffin-based PEG polymers were carried out at temperatures above the melting point. The measurements were carried out at frequencies between 0.4 and 20 GHz. The number of PEG units, m, was varied from 0 to 80 to investigate the effect of the PEG chain length on the dielectric properties of the whole polymer. Findings -With the existence of a dipole moment on PEG but not on pure paraffin, both the real and imaginary part of the dielectric permittivity become larger with increasing chain length of PEG. PEG 3000 showed the highest dielectric constants in the measured frequency range. The effect of the PEG chain length can be explained well by introducing the fraction of molecular weight of PEG divided by the molecular weight of the whole polymer (we call this fraction "Mw fraction of PEG"). Both, real and imaginary part of the dielectric permittivity exhibit a cubic dependence of the molecular weight fraction, and the loss tangent exhibits a linear dependence. These relationships make it possible to predict the microwave heating of the polymer in function of the PEG chain length, carbon chain length and microwave frequency. Originality/value -For the dielectric permittivity of paraffin-based PEG polymers, the effect of the PEG chain length, carbon chain length and applied microwave frequency on the loss tangent was explained well by introducing the molecular weight fraction of PEG.

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The repetitive microwave discharge as a catalyst for a chemical reaction

Cited by 15 publications

References 3 publications

Reaction Enhancement Mechanism of the Nonthermal Discharge and Catalyst Hybrid Reaction for Methane Reforming

Reaction Enhancement Mechanism of the Nonthermal Discharge and Catalyst Hybrid Reaction for Methane Reforming

Process intensification in gas-to-liquid reactions: plasma promoted Fischer-Tropsch synthesis for hydrocarbons at low temperatures and ambient pressure

Effect of PEG number on dielectric properties of paraffin‐based PEG polymers at microwave frequencies

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