Catalytic gasification of biomass model compound in near-critical water

A batch microreactor has been utilized to study the near-critical water gasification of glucose in the presence of metal catalysts. The reaction temperature and pressure were 340–380 °C and 150–250 bar, respectively. The following catalytic activities have been observed: Raney-nickel 4200 > Raney-nickel 3202 > ruthenium on alumina and ruthenium on carbon > Raney-copper > Raney-cobalt. Catalytic gasification of biomass in sub- and supercritical water is a promising process for the production of fuel gaseous. In this paper, a batch microreactor has been utilized to study the near-critical water gasification of glucose in the presence of supported and unsupported metal catalysts consisting of Raney-nickel, Raney-cobalt, Raney-copper, carbon-supported ruthenium, and alumina-supported ruthenium. The reaction temperature and pressure were 340–380 °C and 150–250 bar, respectively. Effects of reaction temperature, reaction time, and catalyst loading on the amount of the generated gas as well as its composition were investigated. Results indicated that within our operating conditions, the conversion of glucose was sensitive to temperature but varying the catalyst loading in the range of 30–100 wt% did not significantly affect the conversion, implying that the experiments were mainly conducted at saturated amounts of catalyst. The following catalytic activities for the decomposition of glucose have been observed: Raney-nickel 4200 > Raney-nickel 3202 > ruthenium on alumina and ruthenium on carbon > Raney-copper > Raney-cobalt. However, the relatively small difference in the gas yields obtained by Raney-copper catalyzed reaction and those of Raney-nickel and ruthenium suggested this relatively inexpensive spongy structure of copper metal could be very useful for gasification of biomass in subcritical water environments.