Users of cars and trucks continually expect higher levels of comfort and ease of use. This has led to a increasing requirements for on-board electrical power. The use of electrical equipment e.g. electrical air condition on-board of vehicles during engine stand still is limited due to the batteries capacity. The only viable energy storage that can supply such consumers is the liquid fuel in the cars tank. A fuel cell based auxiliary power unit (APU) is one possible method of supplying this electrical power. An APU based on a solid oxide fuel cell (SOFC) is theoretically capable of producing electricity with a higher efficiency than an alternator linked to the primary traction engine. Such an APU would be fuelled from the same source as the traction engine, namely diesel or gasoline; and would not have any other special requirements, such as an external supply of water. The fuel/air mixture is converted in the reformer catalyst to a hydrogen and carbon monoxide rich reformate stream directly fed to the fuel cell anode. The SOFC generates electrical energy according to the demand of the customer. Hereby, due to the circumstance that highest electrical efficiencies are reached at incomplete reformate conversion considerable amounts of hydrogen leave the fuel cell anode. Therefore, gaseous residual fuels are burned downstream, the released energy preheats the fuel cell cathode air stream via a heat exchanger. The different components of the APU are integrated together in a hot box. Despite the high temperature level inside (approximately 800 deg C) the surface temperature of the box remains below a critical value. The results of the partial oxidation of Hydroseal in a tubular catalytic reformer equipped with an fuel evaporator is shown. The reaction was started by the introduction of the diesel/air mixture on the preheated catalyst at 400 deg C. Relatively high hydrogen and carbon monoxide concentrations (23 and 22 %) were obtained which were close to equilibrium. Additionally, non methane hydrocarbon (NMHC) concentrations (<1000 mg/Nm3) were also considerably lower than for the intermittent fuel injector, indicating a very high conversion degree.
Reforming of diesel fuel for Auxiliary Power Units (APU)
Reformierung von Dieseltreibstoff für Hilfsstromversorgungsgeräte (APU)
2004
10 Seiten, 3 Bilder, 3 Quellen
Conference paper
English
Reforming of diesel fuel for Auxiliary Power Units (APU)
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