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The current general context for green production and decarbonation prompts considering alternative solutions to produce high added value byproducts from gas decomposition without producing CO2. Steam Reforming or Combustion processes, widely applied in Industry, need H2O or O2 to activate the gas decomposition, originating in CO2 formation in the presence of Hydrocarbon elements. An alternative solution to decompose Hydrocarbon elements without CO2 formation is to activate the decomposition in a high temperature plasma. In that way, there is no need of H2O or O2 to activate the gas decomposition since the plasma is ignited and heated from electron collisions – thermodynamic equilibrium is still governed by neutrals, but electromagnetic energy transfer is governed by electrons. Atmospheric plasmas, also called Thermal plasmas, are much more challenging to be simulated than at low pressure since high gas temperature and skin effect are expected from thermodynamic and electromagnetic coupling. Thermal plasmas used in industry have a low degree of ionization and thus MHD can be neglected.

In this paper, we will present the results obtained with COMSOL Multiphysics® in a 915MHz microwave Argon plasma. Plasma module is used to compute electron density and temperature under microwave exposure. CFD module is used to compute gas flow and coupling with thermal properties. Heat transfer module is used to compute the gas temperature rise according to the thermodynamic properties. RF module is used to simulate the wave propagation at 915MHz and the plasma to waveguide coupling.

The presented model combines the physics observed separately in the models from the Application Libraries: In-Plane Microwave Plasma (Application ID: 8664), Inductively Coupled Plasma (ICP) Torch (Application ID: 18125), Thermal Plasma (Application ID: 8658) and Coaxial to Waveguide Coupling (Application ID: 1863).

The plasma properties and electromagnetic coupling will be compared at low and atmospheric pressure ranges. We will discuss the main differences observed in a glow discharge and a thermal plasma.