【作者】 张锐；

【导师】 李全新；

【作者基本信息】 中国科学技术大学 ， 物理化学， 2025， 博士

【摘要】 木质纤维素生物质的高效转化是实现生物质规模化利用的关键。木质纤维素生物质定向合成生物基航空燃料是生物质能源研究领域的热点课题之一。本论文基于生物质预处理、酶解发酵和乙醇发酵液催化转化过程的耦合,实现了木质纤维素（玉米芯）定向制备生物航空燃料的目标。以玉米芯为原料,探究了生物质均相铁离子催化过氧化氢预处理和非均相CuFeO₂催化预处理方法,旨在通过去除木质素组分提升木质纤维素合成生物航空燃料的效率。通过构建两步级联工艺（醇脱水-烯烃聚合）,实现了醇类分子常压条件下选择性合成生物航空燃料,主要结果总结如下:1)生物质均相催化预处理对生物乙醇及航空燃料合成的影响:针对生物质碱性过氧化氢氧化预处理（AHP）方法对强碱环境的依赖性,探究了一种绿色的铁离子催化过氧化氢预处理（Fe-HP）方法,增强了生物质酶解糖化、乙醇发酵以及生物航空燃料合成的效率。研究表明,与未预处理的玉米芯生物质相比,Fe-HP预处理的玉米芯表现出更高的糖产率（39.2 wt.%）和更高的乙醇产率（35.2 wt.%）。基于生物精炼制备乙醇中间体和热化学催化合成航空燃料的过程耦合,实现了木质纤维素（玉米芯）定向制备生物航空燃料的目标。使用HSAPO-34/Ni Hβ复合催化剂,乙醇转化率达到95.9 C-mol%,航空燃料的选择性达到70.9 C-mol%。结合生物质表征和羟基自由基分析,揭示了在生物航空燃料合成过程中Fe-HP预处理的作用机理。2)生物质非均相催化预处理对生物乙醇及航空燃料合成的影响:针对生物质均相铁离子催化过氧化氢预处理过程中催化剂难以循环再利用的问题,研发了一种绿色可循环的生物质非均相CuFeO₂催化预处理新方法,研究表明,CuFeO₂催化预处理有效地增强了生物乙醇与航空燃料的产率。与未处理的原料相比,利用CuFeO₂催化预处理的生物质为原料,可获得较高的糖产率（39.9 wt.%）和较高的乙醇产率（35.6 wt.%）。当使用CuFeO₂催化预处理的生物质时,乙醇转化率达到94.3 C-mol%,航空燃料的选择性达到64.7 C-mol%。基于催化剂表征和活性氧分析,探讨了CuFeO₂催化预处理过程中催化剂的活性中心、催化剂的构效关系以及催化预处理可能的作用机理。3)低碳醇常压条件下催化制备航空燃料研究:木质纤维素发酵形成的低碳醇或者ABE（乙醇、丁醇与丙酮混合物）可作为合成生物燃料的中间体或平台分子。针对生物质发酵形成的不同低碳醇反应体系的特征,通过有效耦合低碳混合醇催化脱水与烯烃聚合两步反应,实现了常压条件下生物基低碳醇选择性合成生物航空燃料的目标。在低碳醇脱水制取轻烯烃过程,利用优选的Ce@Fe@SAPO-34复合催化剂,增强了低碳醇催化脱水生成轻烯烃的选择性;同时,利用离子液体催化剂,实现了室温常压条件下轻烯烃聚合制备航空燃料的目标。研究了催化剂活性位点、反应参数的影响、不同低碳醇催化转化性能和催化剂的稳定性,探讨了低碳醇和ABE催化合成生物航空燃料的主要反应路径和催化作用机理。更多还原

【Abstract】 The efficient conversion of lignocellulosic biomass is the key to achieving large-scale utilization of biomass.The directional synthesis of bio-based aviation fuel from lignocellulose biomass is one of the hot topics in the field of biomass energy research.Based on the coupling of the processes of biomass pretreatment,enzymatic hydrolysis fermentation and catalytic conversion of ethanol fermentation broth,this thesis has achieved the goal of directional preparation of bio-aviation fuel from lignocellulose（corn cobs）.Using corn cobs as raw materials,the homogeneous iron ion catalytic hydrogen peroxide pretreatment and heterogeneous CuFeO₂ catalytic pretreatment methods were explored,aiming to improve the efficiency of lignocellulose synthesis of bio-aviation fuel by removing the lignin component.By constructing a two-step cascade process（alcohol dehydration-olefin polymerization）,the selective synthesis of bio-aviation fuel from alcohol molecules under normal pressure conditions was achieved.The main results are summarized as follows:1)The effect of homogeneous catalytic pretreatment of biomass on the synthesis of bioethanol and aviation fuel:In view of the dependence of the biomass alkaline hydrogen peroxide oxidation pretreatment（AHP）method on a strongly alkaline environment,a green iron ion catalytic hydrogen peroxide pretreatment（Fe-HP）method was explored,which enhanced the efficiency of biomass enzymatic saccharification,ethanol fermentation and the synthesis of bio-aviation fuel.Studies have shown that compared with unpretreated corn cob biomass,corn cobs pretreated with Fe-HP exhibit a higher sugar yield（39.2 wt.%）and a higher ethanol yield（35.2 wt.%）.Based on the process coupling of biorefining to prepare ethanol intermediates and thermochemical catalytic synthesis of aviation fuel,the directional preparation of bio-aviation fuel from lignocellulose（corn cobs）was achieved.Using the HSAPO-34/Ni Hβcomposite catalyst,the ethanol conversion rate reached 95.9 C-mol%,and the selectivity of aviation fuel was 70.9 C-mol%.Combining biomass characterization and hydroxyl radical analysis,the mechanism of Fe-HP pretreatment in the synthesis process of bio-jet fuel was revealed.2)The effect of heterogeneous catalytic pretreatment of biomass on the synthesis of bioethanol and aviation fuel:Aiming at the problem that the catalyst is difficult to be recycled in the pretreatment process of hydrogen peroxide catalyzed by homogeneous iron ions,a new green and recyclable heterogeneous CuFeO₂ catalytic pretreatment method has been developed.The research shows that the CuFeO₂ catalytic pretreatment effectively enhances the yields of bioethanol and aviation fuel.Compared with the untreated raw materials,using biomass pretreated catalytically with CuFeO₂ as the raw material can achieve a higher sugar yield（39.9 wt.%）and a higher ethanol yield（35.6 wt.%）.When CuFeO₂ was used for catalytic pretreatment of biomass,the ethanol conversion rate reached 94.3 C-mol%,and the selectivity of aviation fuel reached 64.7 C-mol%.Based on the characterization of the catalyst and the analysis of active oxygen,the active centers of the catalyst,the structure-activity relationship of the catalyst and the possible mechanism of catalytic pretreatment during the catalytic pretreatment process of CuFeO₂ were discussed.3)Research on the Catalytic Preparation of Aviation Fuel from Low-Carbon Alcohols under Normal PressureLow-carbon alcohols or ABE（a mixture of ethanol,butanol and acetone）formed by the fermentation of lignocellulose can be used as intermediates or platform molecules for the synthesis of biofuels.In view of the characteristics of different low-carbon alcohol reaction systems formed by biomass fermentation,the goal of selectively synthesizing bio-aviation fuel from bio-based low-carbon alcohols under normal pressure was achieved by effectively coupling the two-step reactions of catalytic dehydration of low-carbon mixed alcohols and olefin polymerization.In the process of low carbon alcohol dehydration to produce light olefins,the preferred Ce@Fe@SAPO-34 composite catalyst was used to enhance the selectivity of low carbon alcohol catalytic dehydration to produce light olefins;Meanwhile,by using ionic liquid catalysts,the goal of preparing aviation fuel through the polymerization of light olefins at room temperature and normal pressure was achieved.The active sites of the catalyst,the influence of reaction parameters,the catalytic conversion performance of different low-carbon alcohols and the stability of the catalyst were studied.The main reaction pathways and catalytic action mechanisms for the catalytic synthesis of bio-aviation fuel by low-carbon alcohols and ABE were discussed.更多还原