Experimental investigation of CO2 valorization by plasma discharges

The availability of efficient storage technologies is nowadays the bottleneck for a wide diffusion of renewable energy sources. A solution would be to use renewable electricity to drive chemical reactions whose products are fuels, the so-called E-fuels, or other chemicals useful as feedstocks for industry. This is the concept of Power-to-X. Non-thermal plasmas generated by electrical discharges in gases are among the promising techniques for tackling this challenge. The non-equilibrium properties of plasmas can be exploited to channel energy in the molecular dissociation rather than in heating the gas, allowing endothermic reactions to take place at relatively low temperatures. One of the main studied processes is CO2 reduction, which enable recycling this greenhouse gas, producing CO, an important feedstock for many fuels and chemicals. The kind of discharge we study is the Nanosecond Repetitively Pulsed (NRP). It works at atmospheric pressure and ensures a high non-equilibrium level thanks to its nanosecond scale duration, which doesn’t allow the energy to redistribute among the different degrees of freedom of the gas. It showed excellent performances in conversion and efficiency both for CO2 reduction and dry reforming of methane. In this work a study on the effect of ethylene addition in the post discharge is presented, together with a technique to accurately estimate the energy dissipartion in the plasma and correctly assess the process efficiency.