生物质组分在催化快速热解中的相互影响

Interactions among the components of lignocellulosic biomass in catalytic fast pyrolysis

对纤维素、半纤维素、木质素及3者不同配比的自配生物质样品进行了热重分析与热解-气象色谱-质谱试验。分析了这3种生物质组分与ZSM-5分子筛进行催化热解反应时的相互影响。结果表明尽管纤维素、半纤维素、木质素初级热解产物不同,但在与ZSM-5分子筛催化热解时最终产物基本一致,主要是芳烃类化合物。然而,木质素组分在催化剂表面形成大量积炭并导致催化剂失活。因此木质素组分会影响纤维素与半纤维素组分在催化热解中的转化,导致生物质的整体转化效率下降,并且抑制作用随木质素含量的提高和反应时间的延长而增强。研究结果表明需要对木质素含量较高的生物质进行预处理,选择性去除木质素,提高生物质整体转化效率,降低催化剂失活。

Thermogravimetric （TG） and pyrolysis-gas chromatograph- mass spectrometer （Py-GC-MS） tests were used to measure cellulose, hemicellulose mixtures for various mass ratios and lignin concentrations and their The interactions among the three components of lignocellulosic biomass were then evaluated after they were catalytically fast pyrolyzed with a ZSM-5 zeolite catalyst. The results show that although cellulose, hemicellulose, and lignin produced quite different primary pyrolysis products, they were converted to similar final products that were predominantly aromatic hydrocarbons in the catalytic fast pyrolysis process （CFP）. the lignin component produced considerable amounts of coke deposits on the zeolite, which resulted in catalyst deactivation. Thus, the presence of lignin interfered with the conversion of the cellulose and hemicellulose components in CFP, resulting in a decrease in the overall aromatic biomass yield containing the three components.Further, the inhibition effects increased with increasing lignin content in the biomass and increased CFP pyrolysis time. The results of this study suggest that for lignocellulose containing high contents of lignin, hiomass pretreatment may be needed to selectively remove the lignin component to improve the overall conversion of biomass and decrease the catalyst deactivation.