秸秆苯酚选择性液化研究

苯酚液化是生物质液化的重要手段,农作物秸秆是一种不均一的原料,而完全液化将其看作是 "单一"的原料,针对这一问题本研究采用选择性液化处理方式对小麦秸秆进行了苯酚液化,并对比了选择性液化与完全液化。结果表明:低温下适当的浓硫酸用量、较高的苯酚用量、适当的反应时间有利于保留纤维素而选择性液化半纤维素和木质素;与完全液化处理方式相比,选择性液化反应条件温和,保留了大量的纤维素,大大提高了原料利用价值。通过均匀试验和数据回归分析并实验验证得到选择性液化优化条件为:浓硫酸用量占总反应体系质量分数的 3.0%,反应温度 100℃,反应时间 30 min,苯酚与秸秆质量比 3:1,纤维素残留率达 70%,而液化产物结合酚质量分数可达 100%。

Study on Selective Liquefaction of Wheat Straw with Phenol

It is an important way to liquefy biomass with phenol. The raw material of wheat straw, which is regarded as homo-geneous material in the complete liquefaction, is actually inhomogeneous. In this paper, a selective way is used to make straw liquefied and differences between selective liquefaction and complete liquefaction are also discussed. Results show that: proper catalyst concentration and reaction time, higher phenol dosage with lower temperature are needed to save cellulose and liquefy hemicellulose and lignin. Compared with complete liquefaction, the selective liquefaction, which is more gentle, can preserve cellulose in order to improve the value of raw material. The optimized conditions for selective liquefaction, which are calculated by multivariate regression equations and validated by experiments, are H₂SO₄ (catalyst mass fraction to whole reaction system, g:g) 3.0%, 100℃, 30 min, phenol:straw ratio (g:g)3:1, in this condition, the residual rate of cellulose is above 70%, and the combined phenol content of the liquefied products can reach 100%.