P-25 広葉樹の半炭化後の組成分析

抄録

To reduce emission of carbon dioxide from coal, co-combustion of biomass and coal is required in Japan. Because torrefied wood has high hydrophobicity and grindability, it is suitable for co-combustion with coal in power plants. Typically, hemicellulose and parts of lignin are degraded at 200-300°C. Decomposition of hemicellulose leads to increase the heating value. On the other hands, hemicellulose should remain as binder for densification. In this study, compositional analysis was performed to investigate the change of components in eucalyptus by torrefaction. Commercially available cellulose and xylan were also torrefied as model compounds. Acid insoluble lignin was apparently increased, but xylan was dramatically decomposed by torrefaction of eucalyptus. Glucose was generated from torrefied cellulose by compositional sugar analysis, suggesting that cellulose could maintain its structure. However, xylose was hardly obtained from torrefied xylan, and it behaved like lignin. These findings were consistent with FT-IR spectra of cellulose and xylose. Therefore, apparent increase of the acid insoluble lignin of torrefied eucalyptus is mainly due to carbonization of xylan.