Production of methane and hydrogen via supercritical water gasification of renewable glucose at a relatively low temperature: Effects of metal catalysts and supports

The activities of various supported catalysts were tested in a continuous flow reactor for production of CH4 and H-2 from glucose via supercritical water gasification (SCWG) at a relatively low temperature (500 degrees C). Based on this preliminary study, among all catalysts tested in this study Ni20%Ru2%/gamma-Al2O3 catalyst was found to be the most active, achieving complete conversion of all carbon in glucose at 500 degrees C and a weight-hourly space velocity (WHSV) of 3 h(-1). The addition of 2% Ru to Ni-20%/gamma-Al2O3 not only suppressed char/tar formation, promoted the carbon gasification efficiently, but also increased methane formation. Moreover, high stability of Ni20%Ru2%/gamma-Al2O3 catalyst was demonstrated in the experimental runs for 20 h on-stream. The roles of ruthenium as a co-catalyst in Ni/Al2O3 were found to be not only increasing nickel dispersion, enhancing nickel's reducibility, but also preventing leaching of Al and Ni metals in SCW. However, NiRu supported on either TiO2 and activated carbon led to lower catalytic activity and frequent plugging after only 3 h on-stream. (C) 2015 Elsevier B.V. All rights reserved.