Conversion of CO2 in a gliding arc discharge reactor: Discharge characteristics and the effects of different parameters

In this work, a knife-shaped gliding arc discharge (GAD) reactor driven by a modulated pulse power supply was used to convert CO2. The discharge image, voltage and current waveforms of GAD were recorded experimentally. The effects of gas flow rate, input voltage, and the duty cycle of power supply on CO2 conversion were studied. A CO2 conversion of 3.8% and energy efficiency of 39.6% could be achieved. Compared with other non-thermal plasmas, GAD has a slightly lower CO2 conversion but higher energy efficiency. In addition, the capacity of CO2 treated by GAD (6 L/min) was significantly higher than other non-thermal plasmas (e.g. 25 mL/min-125 mL/min in corona discharge and dielectric barrier discharge).

Effect of gas flow rate on breakdown voltage in a rotating gliding arc reactor

Understanding breakdown phenomena in rotating gliding arc discharge (RGA) is of interest to tailor them for specific applications. This work revealed that the breakdown voltage in a RGA reactor was not dictated by collisional effects i.e., change in flow rate. The observation was consistent for both the discharge gas medium argon and nitrogen. The collisional effect variation was implemented by varying the operating flow rates i.e., 5 SLPM which is transitional in nature, and 50 SLPM which is turbulent in nature having localized micro-eddies. The observation also indicated failure of Paschen law in RGA having shortest gap between the electrodes of order of mm, operated under atmospheric pressure conditions. Collisional ineffectiveness indicates possibility of streamer formation which needs to be further investigated in future. This work marks preliminary and important step towards understanding the breakdown phenomena in atmospheric RGAs operated under different flow regimes such as laminar/transitional and turbulent.

Plasma-catalytic Efficiency on the Discolouration of Sunset Yellow FCF in a Glidarc Plasma Reactor in Presence of WO₃ Used as Catalyst

In this work, we highlight the plasma-catalytic effect of gliding arc discharge on the bleaching of azo dye sunset yellow FCF in aqueous solution. The effect has been studied in the presence of tungsten oxide as a catalyst in the glidarc reactor. The catalyst has been synthesized via acid precipitation process. The product obtained was characterized by X-ray powder diffraction (XRD), Fourier Transform Infrared (FTIR) and Nitrogen Physisorption. The results showed firstly monoclinic structure of WO3 catalyst. The maximum bleaching rates obtained are 17% and 52.5% after 30 min for initial dye concentration of 25 mg.L-1 for plasma alone and plasma-catalyst, respectively. These results have clearly shown that gliding arc discharge has a double effect, in on hand as a source of hydroxyl radical and on other hands as a source of radiation able to excite the catalyst. The effects of initial pH and photocatalyst loading have been studied.