Pyrolysis gasification reactivities of primary tar and char fractions from cellulose and lignin as studied with a closed ampoule reactor

Gasification reactivities of the cellulose- and lignin-derived primary tar and char fractions were evaluated under the pyrolysis conditions (N-2/600 degrees C/50-120 s) with a closed ampoule reactor. The closed ampoule reactor allowed the precise setting of the residence time and quantitative recovery of the products. The primary tar fraction from cellulose was readily gasified to CO, CO2, CH4 and H-2 while reducing the amounts of the tar components. Contrary to this, the gasification reactivities of the lignin-derived tar fraction and the char fractions from both samples were only one fifth to one sixth of that of the cellulose-derived tar. Although disappearance of the OCH3 structure in the lignin-derived tar fraction was related to the acceleration of formation of the gaseous products and the secondary char, these reactions did not reduce the tar yield effectively. Based on these results, pyrolysis gasification mechanisms of cellulose and lignin are discussed on molecular basis. (C) 2008 Elsevier B.V. All rights reserved.