A micro-structured 5 kW complete fuel processor for iso-octane as hydrogen supply system for mobile auxiliary power units: Part II--Development of water-gas shift and preferential oxidation catalysts reactors and assembly of the fuel processor

For mobile and portable applications of fuel cell technology there is a need for compact hydrogen supply systems [1]. Fuel processors are a viable option for energy supply of fuel cells owing to the high energy density of liquid fuels such as alcohols and hydrocarbon mixtures. A fuel processor is composed of the reformer reactor itself and devices dedicated to remove the carbon monoxide out of the fuel, which is frequently performed by catalytic reactions such as water-gas shift and preferential oxidation [2]. At IMM, a complete fuel processor was developed and put into operation, which was designed to supply a 5 kW fuel cell with purified reformate applying iso-octane as fuel. Iso-octane had been chosen as a model substance for gasoline. Micro-structured plates coated with noble-metal based catalysts were used to build the reactors either as monoliths or as cross-flow plate heat-exchangers. Fig.1a shows a flow scheme of the fuel processor, which was installed on a bread-board level. The test rig itself is shown in Fig.1b. The autothermal reformer (ATR) is shown in Fig.2. It is composed of 200 microstructured metal foils of 400 µm thickness carrying a total of 25,000 channels each 400 µm wide and 250 µm deep. This corresponds to a channel density of 2,520 channels/in and a total surface area of 2.6 m. The reactor has a width and height of 80 mm at a total length of 150 mm. It has a monolithic design. The water/steam mixture generated externally by