Development of Liquid Fuel Reformer Using Low Energy Pulse (LEP) Discharge at Room Temperature

We studied steam reforming of ethanol at room temperature and atmospheric pressure using low energy pulse (LEP) discharge. In this study, we employed characteristic novel reformer, one electrode was made of carbon fibers (o.d. 7.0 μm) bundle. So fuel was supplied to discharge region by capillary action of the fibers and reformed directly by LEP plasma without any pump or heater. When using this reformer, at first, the fuel was evaporated by heat emission from electrode, and then the vaporized reactants were reacted. Produced gaseous compounds were collected from upper part of the reactor, and analyzed by gas chromatography. H2 and other compounds: CO, CH4, CO2, C2H4, and C2H6 were produced, and the formation rates were increased in proportion to the increase of the gap distance and input power. And compared to the former conventional reformer, the results were equivalent to the rates of gas phase reactor. The effects of ethanol concentration and of energy efficiency were studied, and the energy efficiency (LHV based) has reached 89.3 % at the ethanol concentration of 50 %, the discharge gap of 3.0 mm. Introduction Recently fuel cell is attracting attention. Especially, Polymer Electrolyte Membrane Fuel Cell (PEMFC) is one of the candidates. Because it is operated lower temperature than that of other fuel cell, and it has high performance in energy efficiency. Other reasons, clean exhaust gases, small size, light weight, fast start-up, rapid response and so on are also worthy of remark. So PEMFC is expected to serve as a fuel cell vehicle (FCV) and a home cogeneration system. But recent considerable Hydrogen production and transportation processes have many problems with the present technology (for example, The transportation and storage of Hydrogen), so it is need to research innovative technological methods to produce Hydrogen. So, we applied low energy pulse (LEP) discharge for this purpose. If LEP discharge used for reforming, reactions can be achieved at room temperature and atmospheric pressure. On the other hand, ethanol has a potential for being an alternative fuel replacing fossil fuels because ethanol can be produced from various renewable sources. So we tried to unify a supply and storage system with using liquid fuel (ethanol and water solution) and LEP discharge. And it was also attempted to design much smaller reformer, and improve energy efficiency. Experimental Fig. 1-(a) shows our previous fuel delivery system. No catalyst was used, and Ar was used as a carrier gas. Gap distance of electrodes was fixed at 2.1 mm. Our previous reformer was flow type reactor, and the mixture of ethanol and water was supplied by chemical pump, and evaporated at 413 K. The reaction temperature was set at 393 K to prevent condensation into liquid. On the other side, Fig. 1-(b) shows our novel system. The bottom of carbon fiber bundle was soaked into ethanol solution contained in a small bottle. Present reformer was so attractive, because it was no need of heaters or pumps at all. This reformer used carbon fiber bundle as electrode. The solution could be pumped up to the top of the carbon fiber bundle by capillary action and supplied into discharge region. Reactant gas Preheater Liquid Fuel & Water