流通加压热水液化木质生物质

在160～280℃温度范围内，10 MPa，10 mL/min条件下，考察了反应温度对木粉溶解百分比、水溶解部分中半纤维素来源糖类、纤维素来源糖类及降解产物生成的影响，研究了流通加压热水液化生物质的过程。随着温度的升高，木粉溶解百分比逐渐增大，280℃条件下，96.5%的木粉可溶解于水中。水溶解部分中，半纤维素来源糖类和纤维素来源糖类均随温度升高而增大，并分别在250℃和280℃时达最大值，降解产物5-羟甲基糠醛产率和糠醛产率也随温度升高而增大。同时，采用X射线衍射分析水不溶性残渣发现，随着处理温度的升高，残渣相对结晶度逐渐升高，但当温度达到280℃时，相对结晶度骤然下降且（002）晶面衍射峰消失，表明纤维素结晶结构被彻底破坏。残渣的傅立叶红外光谱分析表明，半纤维素在250℃即被完全水解；280℃时，半纤维素和纤维素特征峰均消失，残渣特征峰主要为木质素来源芳香环。研究表明，流通加压热水可以用于木质生物质的全水解来获取糖类。

Liquefaction of woody biomass by flow through hot-compressed water

Flow-through hot-compressed water apparatus was used to study the performance of liquefaction of Japanese beech. The experiments were operated at pressure of 10 MPa, flow rate of 10 mL/min with various temperature from 160℃ to 280℃. The effect of temperature on saccharides from hemicelluloses, saccharides from cellulose and decomposed compounds in water-soluble portion was studied. Water-soluble portion increased with temperature and 96.5% wood could be hydrolyzed into water at 280℃. Both sacchairdes from hemicelluloses and saccharides from cellulose increased with temperature, which reached maximum value at 250℃ and 280℃, respectively. 5-HMF and furfural increased with temperature as well. Meanwhile, X-ray was carried out to investigate the crystallinity of water-insoluble residues. The crystalline index increased with temperature, however, it decreased suddenly at 280℃ and the peak of (002) lattice plane disappeared, which showed that the crystal structure of cellulose was destroyed completely. Furthermore, the typical hemicelluloses peak was disappeared at 250℃ according to FT-IR spectra, which indicated that hemicelluloses were completely hydrolyzed at 250℃. At 280℃, not only hemicelluloses peak but also cellulose peaks disappeared, while characteristic peaks of water-insoluble residue were lignin-derived aromatic skeleton. It is concluded that flow-through hot-compressed water can be used to completely hydrolyze woody-biomass for saccharides production.