抄録
Noticing the color variation of torrefied biomass with pyrolysis process, a non-invasive evaluation method of torrefied biomass properties is investigated. It is assumed that the properties of torrefied biomass mainly depend on its mass yield, and the relationship between mass yields and colorimetric values defined by CIELAB is experimentally examined. The results obtained for torrefied Japanese cedar are as follows. In the case of the trunk sample for L* above 45, the mass yield is expressed as a function of L*, and in the case of the trunk and bark samples for L* below 45, the mass yield is expressed as a function of color coordinate, a*. From the comparison between predicted mass yields and experimental data, it is found that the proposed experimental correlations with the colorimetric values can evaluate the mass yield within an accuracy of ±10%. The energy properties of torrefied biomass such as elemental contents, energy density and energy yield are correlated with the mass yield. When the torrefied biofuel is produced, the quality control concerning energy properties is indispensable, and the optimum mass yield as well as energy properties are easy to be checked by using the present non-invasive method.
