Methanol Fuel Processor for the Sub-watt Power Range

Integrated Methanol Fuel Processor for the Sub-watt Power Range 

Jones et al. [116] presented an integrated and miniaturized device for methanol steam reforming consisting of two evaporators/pre-heaters, a reformer and a combustor with a total volume of 0.2 cm3 for a power range between 50 and 

500 mW, which corresponds to flow rates of 0.03-1 Ncm3 h-1 of methanol/water mixture. 

The energy for the steam reforming reaction was transferred from the combustor device having 3 W power capacity which was fed by an H2/02 mixture for start-up and later by up to 0.2 Ncm3 h 1 methanol and up to 14 Ncm3 h-1 air. The combustor was said to have a volume of 1 mm3, the reformer volume being higher (5 mm3). 

In a second prototype, the reaction temperature was reduced to 250 °C, which reduced the carbon monoxide concentration from 1.2 to 1%. Later, the first fuel processor prototype was linked to a meso-scale high-temperature fuel cell developed at Case Western University by Holladay et al. [117], which was tolerant to carbon monoxide concentrations up to 10%. Hence no CO clean-up was necessary to run the fuel processor. A 23 mW power output was demonstrated according to Holladay et al. [118], This value was lower than expected, which was attributed to several factors. First, the hydrogen supply was lower in the reformate. Second, the presence of carbon monoxide (2%) lowered the cell voltage. Third, the presence of carbon dioxide (25%) generated a magnified dilution effect at the gas diffusion layer material of the fuel cell, which was considerably less porous than conventional materials. 

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