Fundamental processes in CO2-CH4 plasmas: a comparison of experimental and numerical results*

Dry Reforming of Methane (DRM), which converts CO2 and CH4 into value-added products, knows a spike of interest due to it’s potential for energy storage.

Despite extensive literature on pure CO2 or pure CH4 plasmas, the main mechanisms controlling the evolution of CO2-CH4 plasma are not well understood. This works comparing experiments and simulations aims at providing insights on these mechanisms.

To do so, an RF discharge in various mixtures at a few Torr is ignited in a dedicated reactor in static configuration (without any gas flow). The RF voltage is controlled by a signal generator bursting trains of pulses of a few ms with controllable duty cycle ratio. The evolution of the densities of IR active species is monitored between the trains of pulses by FTIR spectroscopy.

These measurements were used to validate a 0D kinetic model using the LoKI simulation tool.

The excited state of dissociation fragments of CO2 and CH4 are found to be crucial, leading to further dissociation. The O(1D) state seems to control the production of water in the plasma via production on OH through oxidation of CH4