Decomposition behaviors of bamboo, chinquapin (hardwood), and Japan cedar (
softwood) in hot-compressed water (HCW) were examined using a HCW flow type
reactor to achieve the maximum utilization of plant biomass. HCW was passe
d through the reactor (3.6 mL) loaded with the biomass sample powder (177-2
50 mu m) at a flow rate of 10 mL/min under 9.8 MPa. The temperature of HCW
was maintained at 180 degrees C for 20 min, after which it was raised to ab
out 285 degrees C at a rate of 5 degrees C/min and maintained at 285 degree
s C for about 7 min. By these operations, free sugars, some of lignin and m
ost of hemicellulose, were first solubilized in water and flowed out during
the initial 20 min flow of HCW. Cellulose started to decompose when the te
mperature of HCW was over 230 degrees C. The orders of elution of these com
ponents were common for three biomass samples, although the amount of produ
cts obtained during the heat-up period up to 180 degrees C and that of resi
due which finally remained in the reactor differed with the samples.