Methanol reforming in supercritical water

The production of hydrogen by the reforming of methanol was studied in a continuously operated tubular reactor made of the nickel-based alloy Inconel 625. Experiments were performed at pressures from 25 to 45 MPa and temperatures in the range of 400-600 degreesC. The concentration of the aqueous feed varied from 5 to 64 wt % methanol. Residence times under reaction temperature conditions varied in the range from 3 to 100 s. The main component of the product gas is hydrogen, with smaller amounts of carbon dioxide, carbon monoxide, and methane. Methanol conversion is up to 99.9% without addition of a catalyst. Obviously, the heavy metals on the inner surface of the reactor influence the composition of the product gas and the conversion rate. Oxidation of the reactor inner surface before gasification turned out to enhance the reaction rate and to decrease the carbon monoxide concentration.