棉秆水热及水热氧化过程水相产物分析研究

水热及水热氧化处理技术可改变生物质的特性,从而提高热解产物的品质及热解效率。本研究使用高压反应釜在180～280℃下对棉秆进行水热及水热氧化过程处理,使用色谱质谱联用仪、波美密度计及pH酸度计对比分析了水热过程水相产物(HTAP)及水热氧化过程水相产物(HOAP)的有机组分、折光指数和pH。结果表明,HOAP中酸类有机物含量最高时的温度(200℃)低于HTAP(230℃)。200～230℃下HOAP中酚类化合物的含量明显高于HTAP。水热氧化过程抑制了HOAP中酮类化合物的生成。180～280℃下HOAP的折光指数高于HTAP,且随着温度增加而下降。HOAP的pH随着温度的升高而增加,并且180～260℃下HOAP的pH低于HTAP。HTAP与HOAP的理化性质和木醋液基本一致,有潜力应用于农业、林业等领域。

Aqueous products prepared by hydrothermal and hydrothermal oxidation processes of cotton stalk

The characteristics of biomass could be changed by hydrothermal and hydrothermal oxidation process, so that the quality of pyrolytic products and pyrolytic efficiency are improved. In this study, the hydrothermal aqueous product (HTAP) and hydrothermal oxidation aqueous product (HOAP) were prepared by the processing of cotton stalk without or with oxidant at 180—280℃ in an autoclave reactor. The organic compounds, refraction indexes and pH values of HTAP/HOAP were investigated using gas chromatography-mass spectrometry, Baume densitometer and pH acidometer, respectively. The results show that the content of the acids in HOAP reached the maximum at 200℃, which is lower than that in HTAP (at 230℃). The content of the phenols in HOAP at 200—230℃ are significantly higher than that in HTAP. The formation of the ketones is inhibited under hydrothermal oxidation. The refraction indexes of HOAP at 180—280℃ show an obvious downtrend with the increase in temperature and are higher than that of HTAP. The pH values of HOAP at 180—280℃ increase with the increasing temperature. Besides, the pH values of HOAP at 180—260℃ are lower than that of HTAP. The physical and chemical properties of HTAP and HOAP are basically the same as those of wood vinegar, which has the potential to be used in agriculture, forestry and other fields.