This work reports the design, fabrication and experimental results of a micro-reformer for hydrogen-rich gas generation from liquid ethanol, for portable-solid oxide fuel cell (SOFC) feeding. Ethanol has been chosen as fuel because its high energy density, easy handling and the possibility of directly obtaining from renewable biomass. The reformer has been designed as a silicon micro monolithic substrate and fabricated by using conventional microelectronics fabrication techniques including photolithography, wet etching, chemical vapor deposition and reactive ion etching. Design and geometry of the system have been optimized for minimizing heat losses in order to satisfy the high temperature requirements of reforming process. The fabricated micro-reformer has dimensions of 15×15 mm~2 in area and 500μm in thickness, with an effective reactive area of more than 36 cm2 consisting of an array of ca. 4.6×10~4 vertical micro channels (50μm diameter). These micro channels have been coated with a noble metal-based catalyst for ethanol steam reforming reaction. The micro-reformer has been successfully tested under diluted feed conditions at the 550-800°C temperature range - optimal operation temperatures for SOFCs - achieving high specific hydrogen production rates, high ethanol conversions (>80%) and adequate selectivity profiles. Results show the increase in contact area between fuel gas and catalyst that leads to a high performance in small volumes and reduced residence times. This functional micro-converter is the basis for a complete gas processing unit to be integrated on an entire micro-SOFC system.
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