Catalyst screening for hydrogen production in mobile systems by the partial oxidation of methanol or hydrocarbons

Several methods of hydrogen supply for mobile fuel cell systems are being evaluated worldwide. For reasons based on full fuel cycle efficiency, available gasoline infrastructure and reaction exothermicity (fast startup), the partial oxidation (pox) of methanol or hydrocarbons to hydrogen and carbon dioxide is of potential interest. The results of catalyst screening for methanol pox have shown significant conversions (80-99%) and hydrogen yields (40-65%) but with hotspots of 50-150 degrees C and carbon monoxide (CO) levels of 2%. The hydrogen rates are equivalent to 20-45 kW(th)/litre reactor volume depending on reaction parameters. In contrast, initial results from hydrocarbon (toluene) pox are dominated by total oxidation giving high conversions (85-95%) but low yields (10-20%) of hydrogen. More screening is required for toluene pox and dynamic experiments with stability tests for the methanol route. Palladium-silver foil membranes were tested to reduce the CO content in hydrogen, but a CO slip of 40 ppm and low permeation rates, 2 W/cm(2), make this option uneconomic with this module design.