[BMIM]HSO_(4)/乙醇降解纤维素残渣的热解行为和产物分布

Pyrolysis behaviors and products distribution of cellulose residue after depolymerized by[BMIM]HSO_(4)/ethanol

以微晶纤维素为原料,利用1-丁基-3-甲基咪唑硫酸氢盐([BMIM]HSO_4)和乙醇组成的二元溶剂体系,在180℃下对其进行催化降解,得到纤维素固体残渣(solid residue,SRE);考察[BMIM]HSO_4的质量分数对SRE结构特征和热解过程的影响规律,为SRE的资源化利用提供理论基础.通过多种手段对样品进行结构表征,结果表明,所得SRE可保持纤维素的化学结构,但随着[BMIM]HSO_4质量分数的增加,SRE的粒径显著降低,其晶体结构逐渐被破环并转化为热不稳定的无定形结构.随着[BMIM]HSO_4质量分数的增加,SRE的热失重起始温度显著降低,热失重曲线向低温区移动.经[BMIM]HSO_4/乙醇降解处理后,挥发分与残渣的气固作用在SRE热解过程中加强,导致焦炭和气体的产率增加,生物油的产率降低.

Solid residue(SRE)was prepared from microcrystalline cellulose conversion by a binary solvent system of 1-butyl-3-methylimidazole bisulfate([BMIM]HSO4)and ethanol at 180℃.The effect of[BMIM]HSO4 mass fraction on the structural characteristics and pyrolysis process was investigated.Characterization results indicated that SRE maintained the chemical structure of cellulose.However,with the increase of[BMIM]HSO4 mass fraction,the particle size of SRE decreased significantly,and the crystal structure was constantly broken which transformed into thermally unstable amorphous structure.With the increase of[BMIM]HSO4 mass fraction,the initial temperature of thermal weight loss was effectively reduced and the thermogravimetric process shifted to low temperature zone.[BMIM]HSO4/ethanol treatment promoted the gas⁃solid interaction between volatile components and residues,leading to the yield of char and gas increasing,and the yield of bio⁃oil decreasing.