Elucidation of the Interaction Among Cellulose, Xylan, and Lignin in Steam Gasification of Woody Biomass

The reaction mechanism for gas and tar evolution in the steam gasification of cellulose, lignin, xylan, and real biomass (pulverized eucalyptus) was investigated with a continuous cross-flow moving bed type differential reactor, in which tar and gases can be fractionated according to reaction time. In the steam gasification of real biomass, the evolution rates of water-soluble tar (derived from cellulose and hemicelluloses) and water-insoluble tar (derived from lignin) decrease with increasing reaction time. It was found that the evolution of water-soluble tar occurs earlier than in the gasification of pure cellulose, indicating an interaction of the three components. The predicted yield of water-insoluble tar is substantially less than that of real biomass. This implies that the evolution of tat-from the lignin component of biomass is enhanced, compared with pure lignin gasification, by other components. The gas evolution rate from real biomass is similar to that predicted by the superposition of cellulose, lignin, and xylan. (c) 2008 American Institute of Chemical Engineers AIChE J, 55: 529-537, 2009