School of Energy and Power Engineering, University of Shanghai for Science and Technology
Changchun Institute of Technology
Department of Energy and Power Engineering, Tsinghua University

水热及水热氧化预处理可以调整生物质内部组分占比,有效促进生物质资源多元化利用。以棉秆为实验原料,经160℃~260℃水热及水热氧化预处理后制备成型炭和活性炭,并使用范式法、热重分析和X射线光电子能谱等测试手段,分析了水热及水热氧化预处理后生物质内部组分的演变对棉秆基成型炭和活性炭的产率、理化性能的影响。结果表明:水热及水热氧化预处理后棉秆中半纤维素和纤维素的分解有利于成型炭的产率和能量密度的增加;与水热预处理相比,水热氧化预处理进一步提高了成型炭的产率及热值,可在一定程度上降低预处理强度;棉秆基活性炭的总产率受预处理产率和活化产率的综合影响;随着水热及水热氧化预处理温度的升高,活性炭总产率呈现先升高后降低趋势,并在预处理温度为200℃获得的最大产率分别为36.95%和29.17%;与原料活性炭相比,水热及水热氧化预处理棉秆基活性炭的前驱体表面含氧官能团含量显著提升,有利于后续的氯化锌活化,得到的活性炭比表面积显著增加,吸附性能更优;此外,在180℃和200℃下水热氧化后的棉秆基活性炭碘吸附值均达到GB/T13803.2-1999制净水用活性炭的二级品标准。

Hydrothermal and hydrothermal oxidation pretreatment can adjust the proportion of biomass components and effectively promote the diversified utilization of biomass re-sources. Cotton stalk was used as the raw material to prepare molded bio-char and activated car-bon by hydrothermal and hydrothermal oxidation pretreatment at 160 ℃-260 ℃. The effects of pretreatment, as well as the evolution of components, on the yield and physicochemical proper-ties of cotton stalk-based molded bio-char and activated carbon were analyzed using methods such as van Soest analysis, thermogravimetric analysis, and X-ray photoelectron spectroscopy. The results show that the decomposition of hemicellulose and cellulose in cotton stalk after hydrother-mal and hydrothermal oxidation pretreatment is beneficial for the increase of molded bio-char yield and energy density. Compared with hydrothermal pretreatment, hydrothermal oxidation pretreatment can further improve the yield and calorific value of molded bio-char, and reduce the pretreatment intensity to some extent. The total yield of activated carbon is affected by the com-bined influence of the pretreatment yield and activation yield. With the increase in hydrothermal pretreatment temperature and hydrothermal oxidation pretreatment temperature, the total yield of activated carbon firstly increases and then decreases, with the maximum yields of 36.95% and 29.17%, respectively, achieved at pretreatment temperature of 200 ℃. Compared with the raw activated carbon, the content of oxygen-containing functional groups on the surface of the precur-sor of cotton stalk-based activated carbon pretreated by hydrothermal and hydrothermal oxidation is significantly increased, which is conducive to the subsequent ZnCl2 activation, and the specific surface area of the obtained activated carbon is significantly increased with improved adsorption properties. In addition, the iodine adsorption values of cotton stalk-based activated carbon after hydrothermal oxidation at 180 ℃ and 200 ℃ can both reach the second grade standard for activa-ted carbon for water purification according to the Chinese GB/T13803.2-1999.

国家自然科学基金项目(51761125011)和吉林省创新创业人才资助项目(2021Y014).

吕邦勇,张守玉,杨济凡,等.水热及水热氧化预处理对棉秆基成型炭和活性炭性能的影响[J].煤炭转化,2024,47(2):86-97

LYU Bangyong,ZHANG Shouyu,YANG Jifan,et al.Effects of hydrothermal and hydrothermal oxidation pretreatment on properties of molded bio-char and activated carbon from cotton stalk[J].Coal Conversion,2024,47(2):86-97