| AVS 61st International Symposium & Exhibition | |
| Plasma Science and Technology | Thursday Sessions |
| Session PS+SE-ThA |
| Session: | Atmospheric Pressure Plasma Processing; Fundamental and Applications |
| Presenter: | Tiago Silva, University of Mons, Belgium |
| Authors: | T. Silva, University of Mons, Belgium N. Britun, University of Mons, Belgium T. Godfroid, University of Mons, Belgium R. Snyders, University of Mons, Belgium |
| Correspondent: | Click to Email |
The increase in global emissions of carbon dioxide (CO2) due to fossil-fuel combustion and other energy-related human activities is strongly related with the global warming issue. Due to this effect, the study of CO2 dissociation process is a highly demanding topic, which requires attention and efficient solutions. Among the proposed strategies, one possible way to limit CO2 emission is to use plasma technology to break the CO2 molecule into oxygen (O) and carbon monoxide (CO), which can be later used for production of valuable chemicals, e.g. for the fuel synthesis (syngas).
Recently, energy-efficient powerful plasma-chemical systems have been developed based on microwave plasmas. These discharges are often generated using electromagnetic waves in the range of 300 MHz to 10 GHz, and can operate over a wide range of conditions of pressure and power. In particular, microwave surfaguide discharges (MSGD) where the gas flow in the discharge tube is perpendicular to the waves propagation, are proven to be good solution for an efficient molecular dissociation of di- or multi-atomic species [1].
In this work, the recent results on CO2-containing MSGD operating at 0.9 GHz and 2.45 GHz in pulsed and continuous regimes are presented. The plasma is sustained in CO2 and CO2+N2 flowing gas mixtures in a quartz tube crossing a copper waveguide. The microwave discharges are characterized in terms of various plasma parameters using various optical emission spectroscopy (OES) methods. In particular, the characteristic plasma temperatures, such as the gas temperature (via CO rotational spectra), and vibrational temperature (via N2 vibrational bands) are determined as a function of time at different axial positions along the gas flow in the discharge tube. The CO2 conversion rate in the discharge volume, along with the measurements of plasma energetic efficiency of such conversion is performed by means of optical emission actinometry. The results of the time- and space- resolved OES measurements demonstrate a non-uniform dissociation rate of CO2 along the gas propagation direction in the discharge. As a result, the dissociation degree can be substantially modified by varying the power balance and the composition of the gas mixture [2]. In addition, in order to get a complete picture of the process, gas chromatography measurements were performed in the post discharge region. The obtained integrated results allow better understanding the µwave plasma-based dissociation of CO2.
[1] T. Godfroid, J. P. Dauchot and M. Hecq, Surf. Coating Technol 174-175 1276-1281 (2003)
[2] T. Silva, N. Britun, T. Godfroid, R. Snyders Plasma Sources Sci. Technol 23 025009 (2014)