Time-resolved in situ measurements and predictions of plasma-assisted methane reforming in a nanosecond-pulsed discharge

Impact of CH4 addition on the electron properties and electric field dynamics in a Ar nanosecond-pulsed dielectric barrier discharge

“…Contrary to what was observed in He [9,13], the electron temperature increased with CH 4 addition. On one hand, holding deposited energy constant, one might expect increasing electron temperatures with decreasing electron number density based on conservation of energy.…”

“…As shown in figure 4, there is a nonlinear decrease in the electron density as the CH 4 percentage of the mixture increases. We have previously studied such a decrease in electron density with He dilution in ns-DBD [9,13]. From the model predictions, it was shown that the addition of CH 4 significantly modifies the breakdown process, resulting in decreases of the peak reduced electric field even with 1% CH 4 addition.…”

“…There is increasing interest in using electricallydriven non-equilibrium plasma discharges for CH 4 reforming and catalysis to process this potent greenhouse gas [3][4][5]. However, most studies rely on ex-situ sampling of products [3,4,[6][7][8] and relatively few experiments make time-resolved in situ measurements of CH 4 -containing non-equilibrium plasmas [9][10][11][12][13]. As a result, the plasma chemistry is not wellunderstood due to the lack of in situ quantification of the plasma properties and species.…”

“…This is in contrast to optical emission spectroscopy or lasercollision induced fluorescence which require a collisionalradiative model for extracting electron properties. Recently, there has been a growing number of laser Thomson scattering studies of nanosecond-pulsed plasmas in the literature [9,[17][18][19]44], but few have focused on volumetric ns-DBDs used previously for plasma-assisted combustion and CH 4 reforming kinetics studies [13,[45][46][47]. Due to the complexity of the plasma chemistry in these plasma-assisted combustion and CH 4 reforming studies, detailed investigations of the plasma properties in a simpler gas mixture containing hydrocarbons would be highly desirable.…”

Relaxation of electronic excitation in nitrogen/oxygen and fuel/air mixtures: fast gas heating in plasma-assisted ignition and flame stabilization

“…It should be noted that most of comprehensive kinetic studies of plasma action on hydrocarbon-containing mixtures are done for strongly diluted conditions and for low specific delivered energies (see, for example, [143], [144]). In particular, it was shown in [145] that a small amount of methane addition (1%) in He will nonlinearly affects the electron energy and number density.…”