Ruthenium(IV) dioxide-catalyzed reductive gasification of intractable biomass including cellulose, heterocyclic compounds, and sludge in supercritical water

Catalytic reduction gasification in the presence of ruthenium(IV) dioxide (RuO(2)) in supercritical water was used to decompose intractable biomass. The gasification of model biomass samples (glucose, cellulose, and heterocyclic compounds), and low-purity biomass samples obtained from a paper-recycling facility (paper sludge) and from a sewage treatment plant (sewage sludge) were studied. In clear contrast to another catalysts, the RuO(2) catalyst completely gasified cellulose to produce mainly hydrogen, methane, and carbon dioxide under various conditions (e.g., 673 K at similar to 30 MPa and 773 K at similar to 50 MPa). As for heterocyclic compounds, nitrogen compounds did not deactivate the RuO(2) catalyst; the gasification of carbazole proceeded completely. Furthermore, paper sludge was almost completely decomposed in supercritical water with RuO(2) at 723 K. (C) 2009 Elsevier B.V. All rights reserved.