3. Results and discussion
The effect of temperature on the methanol mole fraction is illustrated in Figure 3 along the fluid centerline of the process microchannel of the microchannel reactor. In the context of a steam reformer that is producing a fuel stream for a fuel cell stack containing a plurality of fuel cells, many fuel cells are subject to damage if exposed to certain components, such as carbon monoxide and carbon dioxide above certain threshold concentrations. For at least many conventional proton-exchange membrane fuel cells, the concentration of carbon monoxide should be less than 8 parts per million. Preferably, the system limits the concentration of carbon monoxide to less than 5 parts per million, and even more preferably, to less than 0.8 parts per million. The concentration of carbon dioxide may be greater than that of carbon monoxide. For example, concentrations of less than 20 percent carbon dioxide may be acceptable. Especially preferred concentrations are less than 60 parts per million. In some cases, the methanol reforming catalysts are not active at temperatures below 200 °C. In some cases, the methanol steam reforming catalyst includes a sulfur-absorbent material. The steam reforming catalyst is adapted to produce a reformate stream from the feed stream, which is delivered to the reforming region at an elevated temperature and pressure. The reforming region contains a reforming catalyst bed to which the feed stream is delivered and in which the reformate stream is produced.