Abstract The catalytic pyrolysis of biomass is a promising technology for producing high-quality fuels and value-added chemicals. However, the development of this technology has been hindered by high coke formation and low target product yield. In this study, chemical liquid deposition (CLD) was adopted to improve the catalytic performance of HZSM-5 in the catalytic pyrolysis of biomass. The changes of the characteristics, including crystallographic structure, porosity and acidity, of the HZSM-5 zeolite after modification were analyzed by XRD, N2 adsorption-desorption, FTIR and NH3-TPD. The results showed that CLD modification reduced the mesopore volume, pore opening size and the number of external acid sites without changing the micropore structure. Py-GC/MS (a pyrolyzer equipped with a gas chromatography-mass spectrometer) and kinetic analysis were used to analyze the catalytic performance of the parent and CLD-modified zeolites. It was found that the production of aromatics increased first and later decreased, reaching optimal levels at a 4% deposition of SiO2, while the selectivity of monoaromatics increased continuously. Additionally, CLD modification raised the energy barriers for the char/coke formation reactions and could inhibit its production. The deposition amount of 4% showed the best char/coke inhibitory effects for catalytic pyrolysis of cellulose, while the char/coke formation decreased continuously with the increase of the deposited amount of SiO2 for catalytic pyrolysis of lignin.

中文翻译：

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通过化学液相沉积改性的 HZSM-5 提高生物质催化热解芳烃产量

摘要 生物质催化热解是生产优质燃料和高附加值化学品的一项有前景的技术。然而，该技术的发展受到了高焦化率和低目标产品收率的阻碍。在本研究中，采用化学液相沉积（CLD）来提高 HZSM-5 在生物质催化热解中的催化性能。采用XRD、N2吸附-脱附、FTIR和NH3-TPD等手段分析了改性后HZSM-5沸石的晶体结构、孔隙率和酸度等特性的变化。结果表明，CLD 改性在不改变微孔结构的情况下，减少了中孔体积、孔开口尺寸和外部酸位的数量。Py-GC/MS（配备气相色谱-质谱仪的热解器）和动力学分析用于分析母体和 CLD 改性沸石的催化性能。结果表明，芳烃的产量先增加后减少，在 SiO2 沉积量为 4% 时达到最佳水平，而单芳烃的选择性不断提高。此外，CLD 改性提高了炭/焦形成反应的能垒，并可能抑制其生产。4%的沉积量对纤维素的催化热解表现出最好的炭/焦抑制效果，而对木质素的催化热解，随着SiO2沉积量的增加，炭/焦的形成不断减少。结果表明，芳烃的产量先增加后减少，在 SiO2 沉积量为 4% 时达到最佳水平，而单芳烃的选择性不断提高。此外，CLD 改性提高了炭/焦形成反应的能垒，并可能抑制其生产。4%的沉积量对纤维素的催化热解表现出最好的炭/焦抑制效果，而对木质素的催化热解，随着SiO2沉积量的增加，炭/焦的形成不断减少。结果表明，芳烃的产量先增加后减少，在 SiO2 沉积量为 4% 时达到最佳水平，而单芳烃的选择性不断提高。此外，CLD 改性提高了炭/焦形成反应的能垒，并可能抑制其生产。4%的沉积量对纤维素的催化热解表现出最好的炭/焦抑制效果，而对木质素的催化热解，随着SiO2沉积量的增加，炭/焦的形成不断减少。CLD 改性提高了炭/焦形成反应的能垒，并可能抑制其生产。4%的沉积量对纤维素的催化热解表现出最好的炭/焦抑制效果，而对木质素的催化热解，随着SiO2沉积量的增加，炭/焦的形成不断减少。CLD 改性提高了炭/焦形成反应的能垒，并可能抑制其生产。4%的沉积量对纤维素的催化热解表现出最好的炭/焦抑制效果，而对木质素的催化热解，随着SiO2沉积量的增加，炭/焦的形成不断减少。