碱改性HZSM-5热解生物质模型化合物影响研究

实验采用Py-GC/MS在500 ℃下对NaOH、Na₂CO₃和有机碱（CTAB/TPAOH）改性HZSM-5催化热解生物质模型化合物的产物分布影响机制进行探究。结果表明,利用0.1 mol/L NaOH/Na₂CO₃改性HZSM-5使热解油中小分子酮、酚和酯类物质的收率有所提高,有利于碳链长度≥5产物（C_≥5）的生成;0.2 mol/L NaOH/Na₂CO₃改性HZSM-5催化剂有助于脱羰和脱羟基反应的进行,促使环状化合物开裂转化为链状化合物。TPAOH的加入使NaOH改性HZSM-5催化热解产物中酮类产物收率降至18.56%、醛类产物收率增至3.01%,并促使C_≥9产物向C_≤4转化,链状产物增加;经CTAB改性后C_≥9产物向C_5-8转化,环状产物增加。

EFFECT OF ALKALI-MODIFIED HZSM-5 MODIFIED ON CATALYTIC PYROLYSIS OF BIOMASS MODEL COMPOUNDS

In this experiment, Py-GC/MS was used to investigate the influence mechanism of product distribution of biomass model compounds in catalytic pyrolysis of HZSM-5 modified by NaOH、Na₂CO₃ and CTAB/TPAOH at 500 ℃. The results showed that the yield of small-molecular ketones, phenols and esters in the products was increased in catalytic pyrolysis over HZSM-5 modified by 0.1 mol/L NaOH/Na₂CO₃, and the formation of C_≥5 hydrocarbon was enhanced. 0.2 mol/L NaOH/Na₂CO₃ modification HZSM-5 catalyst facilitates decarbonylation and dehydroxylation, and promotes the cracking of cyclic compounds into chain compounds. The yield of ketones in the products decreased to 18.56% and that of aldehydes increased to 3.01% in pyrolysis over HZSM-5 co-modified by utilization of TPAOH and NaOH. Meanwhile, the yield of C_≥9 hydrocarbon decreased in the catalytic pyrolysis, which was due to that C_≥9 hydrocarbon converted to C_≤4 hydrocarbon, and the yield of chain hydrocarbons increased. C_≥9 hydrocarbon in the products converted to C_5-8 hydrocarbon in the pyrolysis over HZSM-5 co-modified by CTAB and NaOH, and the yield of cyclic hydrocarbon increased in this process.