Reaction-engineering approach for stable rotating glow-to-arc plasma : key principles of effective gas-conversion processes

Abstract

This work presents advancements in a rotating glow-to-arc plasma reactor, designed for stable gas conversion of robust molecules like CO2, N2, and CH4. Plasma-based systems play a critical role in Power-to-X research, offering electrified, sustainable pathways for industrial gas conversion. Here, we scaled the reactor’s power from 200 W to 1.2 kW in a CO2 plasma, which introduced instability due to uplift forces and arc behavior. These were mitigated by integrating silicon carbide (SiC) ceramic foam as a mechanical restriction, significantly enhancing stability by reducing arc movement, confining convection, and balancing volumetric flow within the arc. Using high-speed camera analysis and in situ electronic frequency measurements, we identified dominant frequencies tied to operational parameters, supporting potential in operando monitoring and control. Arc-rotation frequencies from 5 to 50 Hz and higher frequencies (500 to 2700 Hz) related to arc chattering reveal the system’s dynamic response to power and flow changes. Furthermore, refining the specific energy input (SEI) to account for plasma residence time allowed for a more precise calculation of effective SEI, optimizing energy delivery to target molecules. Our findings underscore the reactor’s promise for scalable, efficient gas conversion in sustainable energy applications.