Simple Estimation Method for Determining Weight Reduction in Torrefied Wood Chips by Color Data

In this study, we investigated the relationship between weight reduction and color change in torrefied wood chips. We heated Japanese cedar （(cid:9479)(cid:9526)(cid:9533)(cid:9524)(cid:9528)(cid:9523)(cid:9521)(cid:9513)(cid:9526)(cid:9517)(cid:9509)(cid:9444)(cid:9518)(cid:9509)(cid:9524)(cid:9523)(cid:9522)(cid:9517)(cid:9511)(cid:9509) and specimens with dimensions of 29 mm × 29 mm × 5 mm at 200 °C, 230 °C, and 250 °C for 0 − 360 min and then obtained color data. We found correlations between (cid:9488)* and the oven-dry weight ratio after/ before heating （(cid:9499)/(cid:9499) 0 ）, (cid:9488)*+(cid:9509)* and (cid:9499)/(cid:9499) 0 , and (cid:9488)*+(cid:9510)* and (cid:9499)/(cid:9499) 0 . The values of (cid:9488)*, (cid:9488)*+(cid:9509)*, and (cid:9488)*+(cid:9510)* after torrefaction were suitable for accurately and simply estimating the weight reduction of the torrefied chips. Both heartwood and sapwood samples can be used for these estimations without the need to separate them because we found the relationships between the color data and (cid:9499)/(cid:9499) 0 for the heartwood to be very similar to those for the sapwood. However, it is necessary to separate the LR-, LT-, and RT-planes because their corresponding color data and (cid:9499)/(cid:9499) 0 were not similar. Although the torrefied chips become darkened, their grains remain visually distinguishable. トレファクションチップの炭化の程度を正確かつ簡便に得る方法を開発する目的で，半炭化処