Liquid-Phase Fuel Re-forming at Room Temperature Using Nonthermal Plasma

Abstract

A plasma reactor was investigated for fuel re-forming at room temperature. Aluminum or copper chips were placed between the plate electrodes in a vessel filled with oil. An intense plasma due to random sparking was generated between the chips and the plate electrodes to re-form the liquid-phase hydrocarbon fuels to gas and solid phases. 2,2,4-Trimethylpentane, hexadecane, tridecane, and diesel fuel were used as test fuels. When a pulsed square high voltage was applied, transparent hydrocarbon fuels rapidly changed to black due to formation of black powders. During the re-forming, gaseous products were also produced. Hydrogen gas concentration in the produced gas was about 60%−70% when the electrodes and chips consisted of aluminum. The generation rate of the hydrogen gas was 52 mL/min for an input energy of 32 W, with energy efficiency of 7.9 g/kWh. The production rate was proportional to the input energy. The selectivity of CH4 was higher than that of C2H4 when 2,2,4-trimethylpentane was used. On the other hand, the selectivity of C2H4 and C2H2 were higher than that of CH4 when other fuels were used. When the electrodes and chips were made of copper, the production rate was only half of that obtained by aluminum electrodes. The surfaces of the electrodes were analyzed by X-ray diffraction. This analysis demonstrated that a carbon compound (Al4C3) and sulfur compound (Cu5S8) were produced during the re-forming process.