Dry reforming in a dielectric barrier discharge reactor with non-uniform discharge gap: Effects of metal rings on the discharge behavior and performance

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 465; p. 142953
• Main Authors: Wang, Jinxin, Zhang, Kaimin, Meynen, Vera, Bogaerts, Annemie
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-06-2023
• Subjects: Dielectric barrier discharge reactor; Dry reforming; Energy yield improvement; Non-uniform discharge gap; Plasma-based process; Energy yield improvement; Dielectric barrier discharge reactor; Dry reforming; Non-uniform discharge gap; Plasma-based process
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2023.142953

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•The performance of DBD reactors can be enhanced by non-uniform discharge gaps.•The impact of non-uniform gap caused by metal rings on the discharge was unraveled.•The number and cross-sectional diameter of rings affect dry reforming performance.•The reactor with 20 rings with a 3.2 mm cross-sectional diameter performed best.
The application of dielectric barrier discharge (DBD) plasma reactors is promising in various environmental and energy processes, but is limited by their low energy yield. In this study, we put a number of stainless steel rings over the inner electrode rod of the DBD reactor to change the local discharge gap and electric field, and we studied the dry reforming performance. At 50 W supplied power, the metal rings mostly have a negative impact on the performance, which we attribute to the non-uniform spatial distribution of the discharges caused by the rings. However, at 30 W supplied power, the energy yield is higher than at 50 W and the placement of the rings improves the performance of the reactor. More rings and with a larger cross-sectional diameter can further improve the performance. The reactor with 20 rings with a 3.2 mm cross-sectional diameter exhibits the best performance in this study. Compared to the reactor without rings, it increases the CO2 conversion from 7% to 16 %, the CH4 conversion from 12% to 23%, and the energy yield from 0.05 mmol/kJ supplied power to 0.1 mmol/kJ (0.19 mmol/kJ if calculated from the plasma power), respectively. The presence of the rings increases the local electric field, the displaced charge and the discharge fraction, and also makes the discharge more stable and with more uniform intensity. It also slightly improves the selectivity to syngas. The performance improvement observed by placing stainless steel rings in this study may also be applicable to other plasma-based processes.