Gas-phase evolution of Ar/H2O and Ar/CH4 dielectric barrier discharge plasmas
| Autor: | Ruggero Barni, Cristina Riccardi |
|---|---|
| Přispěvatelé: | Barni, R, Riccardi, C |
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
010302 applied physics
Materials science Argon Atmospheric pressure Hydrogen chemistry.chemical_element 02 engineering and technology Dielectric Dielectric barrier discharge Plasma 021001 nanoscience & nanotechnology 01 natural sciences {82.33.Xj}{Plasma reactions} {52.80.Pi}{High frequency discharge} Atomic and Molecular Physics and Optics FIS/01 - FISICA SPERIMENTALE chemistry Physics::Plasma Physics 0103 physical sciences Electric current Atomic physics 0210 nano-technology Rogowski coil FIS/03 - FISICA DELLA MATERIA |
| Popis: | We present some experimental results of an investigation aimed to hydrogen production with atmospheric pressure plasmas, based on the use of dielectric barrier discharges, fed with a high-voltage alternating signal at frequency 30–50 kHz, in mixtures of methane or water vapor diluted in argon. The plasma gas-phase of the discharge was investigated by means of optical and electrical diagnostics. The emission spectra of the discharges was measured with a wide band spectrometer and a photosensor module, based on a photomultiplier tube. A Rogowski coil allowed to measure the electric current flowing into the circuit and a high voltage probe was employed for evaluating the voltage at the electrodes. The analysis of the signals of voltage and current shows the presence of microdischarges between the electrodes in two alternating phases during the period of oscillation of the applied voltage. The hydrogen concentration in the gaseous mixture was measured too. Besides this experimental campaign, we present also results from a numerical modeling of chemical kinetics in the gas-phase of Ar/H2O and Ar/CH4 plasmas. The simulations were conducted under conditions of single discharge to study the evolution of the system and of fixed frequency repeated discharging. In particular in Ar/H2O mixtures we could study the evolution from early atomic dissociation in the discharge, to longer time scales, when chemical reactions take place producing an increase of the density of species such as OH, H2O2 and subsequently of H and H2. The results of numerical simulations provide some insights into the evolution happening in the plasma gas-phase during the hydrogen reforming process. |
| Databáze: | OpenAIRE |
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