不同碱性添加剂和催化剂对稻草共溶剂液化的影响研究

Influence of Alkalic Additive and Catalysts on Straw Liquefaction in Mixed Solvent

以农业典型生物质(稻草)为原料,Na2CO3、K2CO3和FeHZSM-5为液化催化剂,考察了稻草在高温高压反应釜中的液化行为。实验重点考察了不同碱性物质与催化剂的添加对液化实验的影响,添加NaOH、KOH和催化剂在共溶剂和纯水溶剂液化的液效果对比以及NaOH、KOH和催化剂的添加对共溶剂液化产物性质的影响。反应在300℃下进行,碱性物质和催化剂的添加量均为1g。结果表明,碱性物质的添加能有效促进稻草在共溶剂中的液化反应,其中添加NaOH的乙醇-水共溶剂液化效果最好,使产物中油1相产率由38.64%提高到53.27%,转化率由85.31%提高到90.54%。通过对产物GC-MS结果对比表明,NaOH可以提高烷烃类物质在生物油中的比例,催化剂FeHZSM-5可以促进芳香族化合物的生成。

Liquefaction of straw to produce bio-oil in mixed solvent（ ethanol-water mixture ） was carried out in a 1 000 mL autoclave at 573 K. In the present work, the alkalic additives were NaOH and KOH, while the catalysts were Na2CO3, K2CO3 and Fe ion-exchanging HZSM-5 zeolite catalysts, respectively. The results showed that the bio-oil yield increased obviously by the addition of NaOH. In the NaOH run, the bio-oil yield was enhanced from 38.64% to 53.27%, and the conversion of the liquefaction was increased from 85.31% to 90.54%. The hydrothermal liquefaction of straw was studied with the same alkalic additives and catalysts in the mixed solvent liquefaction. Comparing the research results of the two different reaction systems（ mixed solvent system and hydrothermal liquefaction system ）, it indicated that alkalie additives and catalysts were more effective in the mixed solvent system. With the addition of NaOH, the yield of oil 1 in mixed solvent system and hydrothermal liquefaction system was improved by 14.63 % and 2.476%, respectively. The bio-oils were analyzed with gas chromatography-mass spectrometry（ GC-MS ）, and the results indicated that the component characterization of bio-oil was largely depended on catalyst. The amount of hydrocarbon was enhanced in the NaOH run, while amount of aromatic compounds was increased in FeHZSM-5 run.