水熱半炭化木質バイオマスのエネルギ特性に及ぼす半炭化条件の影響

抄録

The torrefied solid biofuels have come to attract attention as promising alternative fuels to coal in coal-fired power plants and industrial boilers．The torrefaction is a thermal treatment conducted by mild pyrolysis temperatures between 180 and 300℃，and includes two distinct technologies，dry torrefaction (DT) and wet torrefaction (WT)．The WT is an attractive thermal treatment to upgrade wet biomass feedstock without pre-drying．In this study，the effect of torrefaction conditions (torrefaction temperature，residence time，ratio of biomass mass to water mass (B/W) on energy properties of wet torrefied woody biomass is investigated．The experimental correlation to estimate HHV of wet torrefied woody biomass for a given torrefaction condition is proposed．From the comparison of net energy ratio (NER) between DT and WT，it is found that the NER of WT is larger than that of DT for wet biomass in the moisture range between 78 and 92%．Therefore，the energy consumption associated with heat drying for wet biomass for WT may be smaller， compared to DT.