Revealing the arc dynamics in a gliding arc plasmatron: A better insight to improve CO₂ conversion

A gliding arc plasmatron (GAP) is very promising for CO₂ conversion into value-added chemicals, but to further improve this important application, a better understanding of the arc behavior is indispensable. Therefore, we study here for the first time the dynamic arc behavior of the GAP by means of a high-speed camera, for different reactor configurations and in a wide range of operating conditions. This allows us to provide a complete image of the behavior of the gliding arc. More specifically, the arc body shape, diameter, movement and rotation speed are analyzed and discussed. Clearly, the arc movement and shape relies on a number of factors, such as gas turbulence, outlet diameter, electrode surface, gas contraction and buoyance force. Furthermore, we also compare the experimentally measured arc movement to a state-of-the-art 3D-plasma model, which predicts the plasma movement and rotation speed with very good accuracy, to gain further insight in the underlying mechanisms. Finally, we correlate the arc dynamics with the CO₂ conversion and energy efficiency, at exactly the same conditions, to explain the effect of these parameters on the CO₂ conversion process. This work is important for understanding and optimizing the GAP for CO₂ conversion.