| Budget Amount *help |
¥4,010,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥510,000)
Fiscal Year 2007: ¥2,210,000 (Direct Cost: ¥1,700,000、Indirect Cost: ¥510,000)
Fiscal Year 2006: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Research Abstract |
In this research, the following results were obtained. (1) Role of lignin-substructures on pyrolytic formation of condensed, depolymerized and carbonized products from wood lignin.
Lignin is a heterogeneous polymer of phenyl propane derivatives, which are linked through various ether (C-O-C) and C-C linkages. Thus, pyrolysis mechanisms of these substructures are very important to understand the pyrolysis of lignin in wood. In this research, various dimeric model compounds were used to study the pyrolysis pathways and mechanisms of the substructures. Then, the results were discussed with the results of pyrolysis of the isolated lignin from wood (lignin polymer). Based on these results, pyrolysis behaviors of the isolated lignin (i.e., condensation, depolymerization and carbonization) were explained with the roles of the pyrolysis of the substructures. Furthermore, the ether cleavage mechanisms (homolysis vs. heterolysis), a key reaction for lignin depolymerization, were identified with v
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arious model compounds. Lignin carbonization is recognized as polyaromatization of the aromatic rings in lignin. The molecular mechanism of this carbonization was proposed for the first time in this research. All these results are essential to control the pyrolysis reactions of lignin for improving the product selectivity.
(2) Role of lignin pyrolysis in wood gasification mechanism
Wood pyrolysis is a key role even in the wood gasification, which is conducted at much higher temperature (800-1000℃) than pyrolysis. The primary pyrolysis products (volatiles and char) are further decomposed into gaseous products (secondary reactions). Thus, the primary pyrolysis is recognized as the source of the reactants to the secondary decomposition stage. Based on the results as described in the section (1), the gasification mechanism of woody biomass was approached at the molecular level. As a result, the behaviors of lignin in wood gasification and the roles of lignin pyrolysis on wood gasification were clarified. These results are very useful to control the gasification process for improving the product selectivity, i.e. tar reduction. Less
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