Naphthalene oxidation by different non-thermal electrical discharges at atmospheric pressure

Abstract

Gaseous naphthalene has been removed by air plasma generated by pulsed corona discharges at 100 °C (LSPM) and dielectric barrier discharges (DBD) up to 250 °C (LPGP) in different reactors geometries. Naphthalene has been chosen as one of unburned hydrocarbon present in exhaust gas engine during the cold start of vehicles. The comparison between the different discharge geometries has been possible using the specific input energy (SIE) as relevant parameter for pollutant removal process control considering the differences in the electrical characteristics and the differences of gas flow. The best naphthalene degradation is obtained in the wire-to cylinder (WTC) corona discharge and the stem-to-cylinder DBD with an energy cost β respectively of 10 and 20 J L −1 . The main by-products issues of the naphthalene oxidation are CO 2 and CO reaching 45% in Multi-Pin-to-Plan corona discharge. We detected polyaromatic hydrocarbons in the gas phase (few ppm) and in the solid phase deposited in the reactors. The introduction of water in the discharges promotes the naphthalene degradation by OH-atom, which has better oxidising power than O-atom in dry air.

The Effect of Packing Material Properties on Tars Removal by Plasma Catalysis

“…16% of γAl 2 O 3 [43]. With regard to the effect of glass beads as a packing material, their utilization in naphthalene removal was also studied by Hübner et al [39] and Redolfi et al [42]. They obtained an NRE of 60 and 95%, however, at higher operating temperatures of 350 and 250 • C and at significantly lower naphthalene initial concentrations of 90 and 100 ppm, respectively.…”

“…It summarizes the general knowledge, recent experiments, results, and findings of various authors. Indeed, several discharges have been employed and investigated in the naphthalene removal process by plasma catalysis: corona discharge [35,36], dielectric barrier discharge (DBD) [37][38][39][40][41][42][43], gliding arc discharge [44,45], and even plasma jet [46]. The discharges have been combined with several catalytic materials, most frequently with Ni-based catalysts (Ni/γAl 2 O 3 [37,38,40,44], Ni/ZSM-5, Ni/SiO 2 [41] and Ni/Co-based catalyst [45]) due to their availability and selectivity towards formation of syngas constituents in catalytic processes [23].…”

Thermal tar cracking enhanced by cold plasma – A study of naphthalene as tar surrogate

“…A final significant parameter is the energy efficiency parameter β (also known as characteristic energy or energy cost) of the model molecule destruction process. It is calculated from plotting the exponential decrease of the model molecule concentration versus SEI, as in equation 5 [51,52] where β and the SEI are given in J/L.…”

Enhanced removal of benzene in non-thermal plasma with ozonation, flow recycling, and flow recirculation

“…Therefore, there is not a concern regarding air pressure and drop of efficiency due to catalyst deactivation in non-catalytic systems. In the application of different excitation power for the plasma systems, there are frequent reports about the elimination of air pollutants in non-thermal plasma systems with DC or AC power [12,[14][15][16][17]. In this line of research, findings in previous research indicated that negative DC discharge is more suitable for dust removal and also reported higher ozone concentration for negative DC discharge systems compared to positive DC discharge systems [18][19][20].…”