Effects of impregnated metal ions on air/CO2-gasification of woody biomass

Abstract

Several impregnated metal ions (Fe (III), Co (II), Ni (II), and Ru (IV)) and a raw iron ore (natural limonite) were examined as catalysts for gasification of pine sawdust in air/CO(2) at 700 and 800 degrees C. The yields of char and tar both increased with increasing CO(2) content in the feed gas. All the impregnated metal ions, in particular Ni (II), Co (II) and Ru (IV), were very effective for promoting biomass gasification in CO(2), leading to greatly reduced yields of tar and char accompanied by significantly enhanced formation of CO and H(2). At 800 degrees C, the impregnation of Fe (III), Ni (II), Co (II) or Ru (IV) led to almost complete conversion of the solid biomass into gas/liquid products, producing an extremely low char yield (<1-4 wt.%), and a very high yield of combustible gas (from 51.7 wt.% for Fe to 84 wt.% for Ru). The tar yield reduced from 32.1 wt.% without catalyst to 19-27 wt.% with the impregnated metal ions.