(415b) Property of Solid Residue in Woody Biomass Saccharization Process by Hot-Compressed Water Method

Liquefaction experiment of wood biomass was conducted in the hot-compressed water process (HCWP). HCWP was able to hydrolyze the wood biomass to saccharine without any acid in a mild operation condition. The operation temperature was usually less than 523 K. Since only the water was used for hydrolysis in HCWP, this process is considered to be clean, simple and economical. However, the HCW hydrolysis efficiency or yield of monosaccharide was usually low rather than that of acid hydrolysis method. Therefore, the hydrolysis mechanism of wood biomass in HCWP has been studied to improve the hydrolysis efficiency and the hydrolysis condition or hydrolysis pathway of cellulose and hemi-cellulose has been understood. A combination approach of HCWP and pulverization was also studied to improve the hydrolysis efficiency of wood biomass, and application studies were started recently. Although, almost all these studies in HCWP were regarding the hydrolysis product analysis in the chemical aspect, the hydrolysis residue characteristics in physical aspect were not studied. To understand the saccharization mechanism of wood biomass and to improve the hydrolysis efficiency, it is very important to analyze or understand not only the hydrolysis product, but also the solid residue of hydrolysis in HWCP. The experiment unit for the scarification of wood biomass was pressurized reactor. Before the liquefaction experiment, the wood biomass slurry was prepared by using the wood powder pulverized by a vibration mill. Wood powder was sieved to 20-100, 100-212, 212-500 um. The reaction temperature set 453 K, and reaction time was controlled for 10-40 min. To evaluate the characteristics of wood biomass residues in HCWP, solid analyses, such as particle size distribution, particle shape and surface area was measured as well as liquid analyses by HPLC. The particle diameter of solid residue decreased with increasing reaction time. On the other hand, surface area and pore sized increased slightly with increasing reaction time. However, the crystallinity was not changed at this reaction temperature. From HPLC result, the materials in the liquid was mostly the decomposed monosaccharide and oligosaccharide from hemi-cellulose. Considering solid analysis and liquid analysis together, hemi-cellulose was decomposed from the surface of wood powder gradually, but cellulose crystal was remained in the wood powder at this reaction temperature.