CO2 valorization by means of dielectric barrier discharge

peer reviewedIn order to reduce atmospheric pollution by CO2 (by transport and industrial applications), CO2 can be used as a source, instead of stocking it as a product. The case considered is the reaction between CO2 and methane producing hydrogen: CO2 + CH4 2 CO + 2 H2 H° = 258.9 kJ/mole. The activation barrier of this endothermic reaction needs to be surpassed. The method of Dielectric Barrier Discharge (DBD) can be used, needing less energy than heating or catalytic pyrolysis. The process relies on the collision of electrons (forming reactive species), accelerated under an electrical field in the discharge area, facilitating the abovementioned reaction. The first step of the simulation in this work presents a 1D model in Matlab (Poisson equation, conservation of electrons and ions), obtaining an average electron and ion density. This is then introduced in a kinetic model of CH4/CO2 dissociation via electron collisions in the discharge region (Reaction Engineering module in COMSOL). Then COMSOL (continuity and Navier- Stokes equations) is used to model the flow in the post-discharge phase (reactions between vibrationally excited CO2 and CH4). Preliminary calculations for a plasma reactor model show that when the reactor wall is heated at 1000K, without electrical discharge, the decomposition of CO2 is 7.5%. With electrical discharge, the same decomposition is attained at a lower temperature, namely 880K