63. Byrd, Adam J.; Pant, K. K.; Gupta, Ram B.. Hydrogen Production from Ethanol by Reforming in Supercritical Water Using Ru/Al2O3 Catalyst. Energy & Fuels (2007), 21(6), 3541-3547.
Supercrit. water is a promising reforming media for the direct prodn. of hydrogen at high pressures with a short reaction time. In addn. to being a dense solvent, supercrit. water also participates in reforming reaction. In this work, high-pressure hydrogen is produced from ethanol by reforming over a Ru/Al2O3 catalyst with low methane and carbon monoxide formation. Expts. were conducted in a continuous tubular reactor to study the effects of temp., pressure, residence time, and water-to-carbon ratio on the H2 yield. Hydrogen formation is favored at high temp. and at high water-to-ethanol ratio. The formation of methane can be suppressed by operating at an optimal residence time, high reactor temp., and a low feed concn. of ethanol. Excellent conversion in reaction time as short as 4 s is achieved. Pressure has a negligible effect on hydrogen yield above the crit. pressure, and for <10 wt. % ethanol concn. in the feed, there was negligible coke formation. On the basis of the products obtained, a reaction mechanism is discussed. An activation energy of 65.3 kJ mol-1 was obsd.