Étude du reformage d'hydrocarbures liquides assisté par plasma hors-équilibre pour la production de gaz de synthèse

摘要

The direct use of hydrogen as an energy vector currently faces difficulties due to both the lack of a distribution infrastructure, and to technical limitations concerning hydrogen storage. Before the transition to a “direct hydrogen” economy, a possible intermediate step could be the onboard hydrogen production from conventional car fuels. Non-thermal, plasma-assisted reforming provides an alternative to conventional industrial catalytic reforming, since the latter has limitations when an onboard system. The objective of this work is the characterization of plasma assisted reforming technology, through various parametric studies (factors influencing flow – geometry of the cylindrical electrode, pattern of behaviour, pressure, polarity – and factors influencing chemical conditions – initial mixture, total flow rate, injected electrical power, nature of combustible components), on both experimental and theoretical fronts. A study of the behaviour of the torch in non-reactive conditions (steam water, air) was first performed. The reforming reaction was then studied under various conditions (POx, SR, ATR), using gasoline SP95, ethanol, E85 and diesel fuel; establishing the adaptability of the reactor. A simple physical model of the arc was also developed in the case of air. The modelling of the reactor focused then on different aspects. Firstly, the study of flow showed that the good mixing between the three reactive species (air, water, octane) was attained quickly during their injection in the reactor, conferring an axial symmetry on the system. The study of a 1D kinetic model then served to highlight the role of radicals in the activation of the reaction of reforming. This was followed by a sensitivity analysis. A coupled model taking into account correlation between flow (2D axisymetric) and the reactions of chemical kinetics was finally worked out, with emphasis placed on the sequence of reactions in the reactor as a whole.