Abstract
Hydrothermal treatment of biomass to produce useful chemicals has been investigated by many researchers. We proposed a technique to obtain useful chemicals (e.g. sugars, organic acids and furfurals) from biomass feedstock using two-step hydrothermal treatment system which combined steam explosion and hot liquid water reaction. However, a cretin amount of unreacted residue was discharged as wet solid from this system. In this study, hydrothermal carbonization was investigated in order to convert the wet biomass residue into charcoal in liquid phase. If the produced wet charcoal can be used as charcoal water slurry fuel, an efficient energy production system will be attained.
We carried out the hydrothermal carbonization experiment about the residue that is discharged from the proposed two-step hydrothermal treatment of unused forest biomass (e.g. Japanese cedar, bamboo). From the results, it was found that the charcoal obtained by treating at 250°C has higher calorific value of 27∼28 MJ/kg-dry basis. This process is lower temperature that carbonization of biomass usually occur in a hot compressed water. Thus, it has possibility that fuel is produced by inputting a little energy to the biomass residue.
