International audienceCoal gasification and natural gas reforming are regarded as mature technologies for syngas production. These technologies are however highly polluting in terms of greenhouse gas emissions; mainly carbon dioxide. Natural gas reforming is considered cleaner than coal gasification but has some disadvantages in terms of plant maintenance and processing costs as they utilize catalysts which are prone to poisoning; are costly; and require regular regeneration. In mitigation of these issues, plasma-based CO2 dissociation technologies could probably offer a new alternative for syngas production. The plasma-based technologies are more compact, have faster response and reaction time, and are relatively cheaper compared to conventional gasification and reforming. Assuming that electricity is produced by a low carbon emitting (renewable or nuclear) power plant, a comparative review of CO2 dissociation technology for syngas production shows that CO2 dissociation can be competitive from an environmental point of view, but would face several challenges with the current plasma technologies available. Indeed, the results show that for current plasma processes to be competitive with conventional processes for syngas production, the energy efficiency, conversion rate, and processing mass flow rates of the unit operations would have to be simultaneously increased. Syngas production would also be highly dependent on the specific energy input and characteristics of the plasma (technology, electric field, power, etc.). CO2 dissociation would give value to carbon dioxide as it consumes 0.33 moles of CO2 for each mole of syngas produced. Therefore, CO2 dissociation can be attractive as a possible option for the conversion of electrical energy to chemical energy, especially when the electrical energy is from a renewable and low cost electricity production. Keywords: carbon dioxide, CO2 dissociation, syngas production, reforming, plasma, coal gasification, natural gas reformin

A pin–pin electrode geometry was used to study the velocities of streamers propagating over a flat dielectric surface and in gas close to the dielectric. The experiments were done in an argon atmosphere, at pressures from 0.1 to 1 bar, with repetitive voltage pulses. The dielectric surface played a noticeable role in discharge ignition and propagation. The average speed of the discharge decreased with higher pressure and lower voltage pulse rise rate. It was higher when the conductive channel between the electrodes was formed over the dielectric, rather than through the gas. Space resolved measurements revealed an increase in velocity of the discharge as it travelled towards the grounded electrode.

International audienceThis paper presents a simplified one-dimensional kinetic model (phenomenological approach) of a nonthermal are discharge plasma reactor used for n-octane reforming. After a description of the model and its main assumptions, a parametric analysis of plasma reformer performance addressing the influence of plasma volume, H2O/C ratio, O/C ratio, and input electric power is presented. Results focusing on energy efficiency and conversion rate, including comparison with experimental gasoline reforming data, are analyzed and discussed. The parametric study has provided an optimum for actual plasma reformer, H2O/C = 0, O/C = 1.1, and input electric power between 20 and 25% LHV. The model shows that nonequilibrium chemistry is produced via fast mixing of arc plasma jet and reactants to quench radicals and other active species generated in the high-temperature region

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