Abstract
As a key process of the biomass refinery, we have developed an atmospheric pressure superheated steam (SHS) biomass pyrolysis process that produces both carbonized materials and water solution of valuable chemicals (ca. monomeric phenols) from wood or agricultural residue. In this process, undesirable oily compound (SHS-tar) was also produced, which makes many operational problems. In this study, the production of the SHS-tar during SHS pyrolysis of Sugi (Japanese cedar, a softwood) was investigated in various temperature conditions using a small-scale batch type reactor. As a result, the tar yield was slightly increased with the pyrolysis temperature. In the case of 400°C, about 10 % of carbon contained in Sugi was converted into SHS-tar including phenol, guaiacol, methyl guaiacol, and ethyl guaiacol. Furthermore, high temperature compressed water (HCW) decomposition was performed to recover the monomeric phenols from SHS-tar. The experiment using a batch-type HCW reactor indicated that the monomeric phenols were eluted in water-phase by HCW treatment in the range of 250∼350°C under saturated vapor pressure. Furthermore, ethylguaiacol was increased as a result of HCW treatment. This production was, however, accompanied with the secondary reaction (polymerization), and the optimum condition to obtain the ethylguaiacol in this study was 350°C HCW treatment in 20 minutes including warm-up period.
