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

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.L’utilisation directe d’hydrogène comme vecteur énergétique pour des applications embarquées doit actuellement faire face à l’absence d’infrastructure de distribution et à des difficultés technologiques liées au problème du stockage de l’hydrogène. Une étape transitoire possible avant le passage à une économie «direct hydrogène» consiste à produire l’hydrogène à bord du véhicule à partir des carburants automobiles traditionnels. Le reformage assisté par plasma hors équilibre constitue une alternative au reformage catalytique qui, bien que largement utilisé à l’échelle industrielle, reste peu adapté aux contraintes des systèmes embarqués. Ce travail s’inscrit dans le cadre de recherches menées depuis une quinzaine d’années par le Centre Énergétique et Procédés, dans le domaine de la conversion d’hydrocarbures par plasma. L’objectif de ce travail a été la caractérisation précise du dispositif de reformage assisté par plasma, à travers différentes études paramétriques (influence de l’écoulement – géométrie de l’électrode cylindrique, régime de fonctionnement, pression, polarité – et influence des conditions chimiques – mélange initiale, débit total, puissance électrique, nature du carburant précurseur), conduites tant sur le plan expérimental que théorique.Une étude du comportement de la torche dans les conditions non-réactives (eau, air) a d'abord été effectuée. La réaction de reformage a ensuite été étudiée suivant des conditions variées (POx, SR, ATR) et à l'aide d'essence SP95, d'éthanol, d'E85 et de gazole ; prouvant le caractère versatile de la technologie.Un modèle simple d'arc a été développé dans le cas de l'air. La modélisation du réacteur a ensuite concerné différents aspects. L'étude de l'écoulement, tout d'abord, a permis de montrer que le mélange homogène entre les trois réactifs (air, eau, octane) était rapidement atteint lors de leur injection dans le réacteur, conférant au système une symétrie axiale. L'étude d'un modèle cinétique 1D a ensuite mis en évidence le rôle des radicaux dans l'activation de la réaction de reformage, et a donné lieu à une étude paramétrique poussée (mélange initial, débit total, puissance injectée, schéma cinétique utilisé). Un modèle couplé prenant en compte l'interaction entre l'écoulement 2D axisymétrique et les réactions de cinétique chimique a enfin été élaboré, mettant l'accent sur le déroulement de la réaction dans l'ensemble du réacteur

Characterization of a low current-high voltage air arc discharge at high pressure

http://icpig2007.ipp.cas.cz/files/download/cd-cko/ICPIG2007/pdf/3P10-97.pdfInternational audienc

Optimisation de la géométrie d'une torche plasma pour le réformage de l'essence

International audienceL'hydrogène est potentiellement considéré comme un vecteur énergétique du futur, se substituant aux hydrocarbures liquides actuels. La production d'hydrogène embarquée par exemple pour l'alimentation d'une pile à combustible reste néanmoins un enjeu technologique de taille

Device for generating hydrogen by fuel reforming using electric discharge generating plasma, comprises first cylindrical element within which reactive mixture flows, second element forming electrode tip, and continuous current generator

The hydrogen generating device comprises a first cylindrical element (1) within which a reactive mixture flows, a second element (2) forming an electrode tip (6) arranged along the axis of the first element, and a continuous current generator to establish a potential difference between the elements. The first cylindrical element comprises a conductive area to define with the second element, an area to establish an electrical discharge, a cylindrical electrode (4), and a first cylindrical insulating sleeve (3) closed at the side of the second element. The hydrogen generating device comprises a first cylindrical element (1) within which a reactive mixture flows, a second element (2) forming an electrode tip (6) arranged along the axis of the first element, and a continuous current generator to establish a potential difference between the elements. The first cylindrical element comprises a conductive area to define with the second element, an area to establish an electrical discharge, a cylindrical electrode (4), and a first cylindrical insulating sleeve (3) closed at the side of the second element. A unit for continuously vary the distance between the first conductive area of the first cylindrical element and the second element to vary the length of electric discharge along a flow of the reaction mixture and/or the fuel nature. The cylindrical electrode is mounted within the first insulating sleeve. The cylindrical electrode of the first cylindrical element is rotating along the axis of the first cylindrical element. A second insulating cylindrical sleeve is applied on the inner surface of the cylindrical electrode. The cylindrical electrode is motionless, and the second insulating sleeve is rotating along the axis of the first cylindrical element. A conductive area is delimited by an electrical insulation element. The electrode is stationary, and the second element forming an electrode tip is rotating along its axis. The cylindrical electrode comprises an alternating conductive element and electrically insulating elements along its axis defining a succession of coaxial conducting rings separated from one another. A switching device is able to select the active conducting part, and the other conductive parts are electrically insulated. The movable cylindrical electrode of the first cylindrical element comprises a slit provided for injection of reactive mixture. The slit cut in the cylindrical electrode of the first cylindrical element having a size equal to the flow of cylindrical electrode. The first insulating sleeve comprises a hole provided for the injection of reactive mixture and arranged opposite to the slit. The slits are each cut into the cylindrical electrode against each holes provided in the sleeve. The length of the slits has a size less than the flow of the cylindrical electrode. The holes of the first sleeve are diametrically opposite with respect to the other with respect to the axis of the first cylindrical element. The second element comprises a helical groove, dug in the element such as in insulation. Earth is coupled to the conductive area of the first cylindrical element, or to the pointed electrode of the second element. An independent claim is included for a process for generating hydrogen by fuel reforming

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

PARIS-MINES ParisTech (751062310) / SudocSOPHIA ANTIPOLIS-Mines ParisTech (061522302) / SudocSudocFranceF

Ethanol and E85 reforming assisted by a non-thermal arc discharge

Conference Information: 10th International Conference on Petroleum Phase Behavior and Fouling, Rio de Janeiro, Brazil, June 2009International audienceEthanol reforming could provide an interesting path for on-board hydrogen production from renewable resources for fuel cell powering. This paper presents a study on hydrogen production from both pure ethanol and E85 with a plasma reactor. Reforming of ethanol was systemically tested with a non-thermal arc discharge system based on a high voltage/low current power source. A short review on ethanol reforming is first presented as a reference point for this study. Effects of supplied power for plasma generation, air/fuel ratio, and addition of water were then experimentally investigated. Those results were at last compared with a 1D multistage model, exhibiting good correlation. In spite of the early stage of research, a fair conversion rate and fair H2 yields have been achieved (90% and 65%, respectively). The optimal conditions for ethanol reforming are found to be at an oxygen ratio higher than the reaction's stoichiometry, with a slight addition of steam. Discussion is provided concerning the non-thermal plasma effect on the ethanol reforming

Theoretical and experimental analysis of non-thermal arc discharge assisted reforming of gasoline

International audienceOn-board hydrogen production by means of hydrocarbon reforming systems is an attractive option for the development of fuel cells in vehicles. Interest on plasma as an alternative to classical catalytic reforming systems has increased in recent years. A discussion covers advances in non-thermal plasma reforming of commercial hydrocarbons: gasoline and E85 (85% ethanol 15% gasoline); plasma technology based on a low current-high voltage tip/cylinder configuration discharge; and modeling approaches; that can simulate the reforming of hydrocarbons, e.g., methane, gasoline, and E85 over a wide range of conditions